pavement preservation: practices, research …
TRANSCRIPT
NCHRP Project No. 20-07, Task 184
PAVEMENT PRESERVATION: PRACTICES,
RESEARCH PLANS, AND INITIATIVES
FINAL REPORT
Prepared for: National Cooperative Highway Research Program
Transportation Research Board National Research Council
D.G. Peshkin and T.E. Hoerner Applied Pavement Technology, Inc.
3010 Woodcreek Dr., Suite J Downers Grove, Illinois 60515-5415
APTech Project No. 03-126-RR1
May 2005
ACKNOWLEDGEMENT OF SPONSORSHIP
This work was sponsored by the American Association of State Highway and Transportation Officials, in cooperation with the Federal Highway Administration, and was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Research Council.
DISCLAIMER
This is a final report as submitted by the research agency. The opinions and conclusions expressed or implied in the report are those of the research agency. They are not necessarily those of the Transportation Research Board, the National Research Council, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, or the individual states participating in the National Cooperative Highway Research Program.
PAVEMENT PRESERVATION: PRACTICES,
INITIATIVES, AND RESEARCH PLANS NCHRP Project 20-07, Task 184
FINAL REPORT
Prepared for: National Cooperative Highway Research Program
Transportation Research Board National Research Council
D.G. Peshkin and T.E. Hoerner Applied Pavement Technology, Inc.
3010 Woodcreek Dr., Suite J Downers Grove, Illinois 60515-5415
APTech Project No. 03-126-RR1
May 2005
TABLE OF CONTENTS
LIST OF FIGURES ............................................................................................................... iv
LIST OF TABLES....................................................................................................................v
ACKNOWLEDGMENTS................................................................................................... vii
ABSTRACT ............................................................................................................................. vii
CHAPTER 1. INTRODUCTION.......................................................................................1 INTRODUCTION..............................................................................................................1 PROJECT OBJECTIVE...................................................................................................3 PROJECT APPROACH ...................................................................................................3 REPORT OVERVIEW .....................................................................................................4
CHAPTER 2. OVERVIEW OF PAVEMENT PRESERVATION PRACTICES...............................................................................................................................5
INTRODUCTION..............................................................................................................5 PAVEMENT PRESERVATION DEFINITIONS...........................................................6 PAVEMENT PRESERVATION QUESTIONNAIRE ...................................................8 SUMMARY OF PREVIOUS SURVEYS OF SHA PAVEMENT PRESERVATION PRACTICES ....................................................................................................................10 2004 SURVEY RESULTS ...............................................................................................13 SUMMARY ......................................................................................................................23
CHAPTER 3. SUMMARY OF RECENT PAVEMENT PRESERVATION RESEARCH..............................................................................................................................25
INTRODUCTION............................................................................................................25 SUMMARY OF RECENT PAVEMENT PRESERVATION-RELATED RESEARCH .....................................................................................................................26
Treatment Selection Procedures/Guidelines ...........................................................27 Treatment Timing ......................................................................................................39 Innovative Materials and Construction Techniques ..............................................42 Materials Selection and Mix Design.........................................................................45
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TABLE OF CONTENTS (continued)
Treatment Performance ............................................................................................46 Specifications ..............................................................................................................83
SUMMARY ......................................................................................................................86
CHAPTER 4. PAVEMENT PRESERVATION RESEARCH NEEDS .............89 INTRODUCTION............................................................................................................89 PREVIOUSLY IDENTIFIED RESEARCH NEEDS ...................................................89
Maintenance Research Master Planning Workshop (2000) ..................................89 Foundation for Pavement Preservation (2001) .......................................................91 Caltrans Workshop (2001) ........................................................................................91 Strategic Highway Research (2001) .........................................................................92 Infrastructure Research and Technology Stakeholder Workshop (2002) ................95 Survey of AASHTO Member Agencies (2003) ........................................................95 TRNews Issue on Highway Infrastructure Preservation (2003) ...........................96
ASSESSMENT OF CURRENT RESEARCH NEEDS ..............................................101 Information Sharing ................................................................................................102 Materials Selection and Mix Design.......................................................................103 Selection of Treatments and Treatment Strategies ..............................................108 Construction .............................................................................................................111 Treatment/Pavement Performance ........................................................................115 Specifications ............................................................................................................119 Policy .........................................................................................................................121 Training ....................................................................................................................121
SUMMARY ....................................................................................................................123 SUGGESTIONS FOR ADDITIONAL RESEARCH .................................................124
High Priority Research Topics ...............................................................................124 Medium Priority Research Topics .........................................................................126 Low Priority Research Topics ................................................................................127
RECOMMENDATIONS...............................................................................................129
REFERENCES ......................................................................................................................130
APPENDIX A—PAVEMENT PRESERVATION SURVEY QUESTIONNAIRE ....................................................................................................... A-1
ii
APPENDIX B—SUMMARY OF PAVEMENT PRESERVATION SURVEY QUESTIONNAIRE RESPONSES............................................................................B-1
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LIST OF FIGURES
Figure No.
1 Distribution of the ages of in-place pavement preservation programs (as of 2004) ......... 15 2 Amount of dedicated agency funding for pavement preservation in 2004 ....................... 16 3 Distribution of roadway classifications on which agencies apply preventive maintenance
treatments. ......................................................................................................................... 18 4 Distribution of the percentage of preventive maintenance projects placed on pavements in
different condition categories (averages of all agency responses).................................... 19
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LIST OF TABLES
Table No.
1 Benefits and limitations of using decision trees and matrices (Hicks, Seeds, and Peshkin 2000).................................................................................................................................. 30
2 Examples of recent and ongoing materials selection and mix design-related research .... 47 3 Prioritized research projects .............................................................................................. 93 4 Summary of 2003 PPETG survey results.......................................................................... 96 B-1 Questionnaire primary respondent information ................................................................B-3 B-2 Summary of agency familiarity with pavement preservation and preventive maintenance
research being conducted by other agencies (Question 1) ................................................B-5 B-3 Summary of whether or not agency research decisions would be influenced by ongoing
research in other agencies (Question 2) ............................................................................B-6 B-4 Summary of past, current, and future research activities and interests (Question 3)........B-8 B-5 Summary of interest rankings averages and a ranking of Topic IDs based on interest ..B-13 B-6 Summary of whether or not agencies currently have a pavement preservation program in
place (Question 4) ...........................................................................................................B-14 B-7 Summarized assessment of pavement reservation program complexity (Question 5a) ..B-15 B-8 Summary of the number of years that current pavement preservation programs have been
in place (Question 5b) .....................................................................................................B-16 B-9 Summarized assessment of the maturity of agency pavement preservation programs
(Question 5c) ...................................................................................................................B-17 B-10 Summarized assessment of the benefits being realized by in place preventive maintenance
programs (Question 5d)...................................................................................................B-18 B-11 Table B-11. Summary of prioritized agency goals of their preventive preservation
program (Question 6) .....................................................................................................B-20 B-12 Summary of agency interest in implementing a pavement preservation program for those
agencies currently without a program (Question 7) ........................................................B-21 B-13 Summary of common implementation obstacles faced by agencies (Question 8)..........B-22 B-14 Summary of the most significant obstacles to implementing a pavement preservation
program as identified by agency responses to question 9 ...............................................B-24 B-15 Summary of agencies with dedicated pavement preservation budgets
(Question 11, part 1)........................................................................................................B-31 B-16 Summary of agency funds dedicated to pavement preservation practices in 2004 (Question
11, part 2) ........................................................................................................................B-32 B-17 Characterization of the funding administration and distribution methods used by
responding agencies (Question 12) .................................................................................B-33 B-18 Summary of facility type characteristics associated with projects selected as candidates for
pavement preservation projects (Question 13)................................................................B-35
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LIST OF TABLES (continued)
B-19 Summary of the percentage of preventive maintenance projects placed on pavements in different condition categories (Question 14)...................................................................B-35
B-20 Summary of whether or not agencies apply more than one preventive maintenance treatment over the life of a pavement (Question 15).......................................................B-37
B-21 Summary of typical purposes for applying preventive maintenance treatments (Question 16)....................................................................................................................................B-39
B-22 Summary of treatment type usage and interest for treatments on HMA-surfaced pavements (Question 17)...................................................................................................................B-40
B-23 Summary of treatment type usage and interest for treatments on PCC-surfaced pavements (Question 17)...................................................................................................................B-41
B-24 Summary of methods used by agencies to select a preventive maintenance treatment for a given pavement (Question 18) ........................................................................................B-42
B-25 Summary of agency responses indicating whether or not pavement preservation activities are tied to the agency’s pavement management system (Question 19)...........................B-43
B-26 Summary of the status of the integration of pavement preservation and pavement management activities (Question 19a) ...........................................................................B-45
B-27 Summary of methods used to select the timing of preventive maintenance treatments (Question 20)...................................................................................................................B-46
B-28 Summary of whether or not agencies use pavement management data to optimize the timing of preventive maintenance treatments (Question 21) ..........................................B-47
B-29 Summary of whether or not agencies track the performance of their preventive maintenance treatments (Question 22) ............................................................................B-48
B-30 Summary of whether or not agencies have analyzed treatment data to estimate expected treatment lives (Question 23) ..........................................................................................B-50
B-31 Summary of agency assessment of the quality of their preventive maintenance treatment specifications (Question 26)............................................................................................B-54
B-32 Summary of whether or not agencies have QC/QA procedures in place for preventive maintenance treatments (Question 27) ............................................................................B-56
B-33 Summary of agency usage of warranty specifications with preventive maintenance treatments (Question 28) .................................................................................................B-58
B-34 Summary of agency usage of performance-related specifications with preventive maintenance treatments (Question 29) ............................................................................B-59
B-35 Summary of the familiarity with the four NHI pavement preservation courses (Question 30)....................................................................................................................................B-61
B-36 Summary of whether or not agencies have trained personnel on preventive maintenance concepts and/or techniques (Question 31) ......................................................................B-62
B-37 Summary of whether or not agencies have a technician certification program that includes preventive maintenance treatments (Question 32) ..........................................................B-63
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ACKNOWLEDGEMENTS
The research reported herein was performed under NCHRP Project 20-07, Task 184, by Applied Pavement Technology, Inc. David G. Peshkin was the Principal Investigator, and all work under this project was performed under his general supervision. The co-author of this report is Todd E. Hoerner, also of Applied Pavement Technology, Inc.
In addition to these authors, review of this work was provided by Kathryn A. Zimmerman of
Applied Pavement Technology, Inc. Technical review of the survey tool was provided by the project’s technical panel, which provided very useful input. Of course, this report would not have been possible without the cooperation and contributions of the 35 agencies that took the time to respond to the lengthy survey. Their time and efforts are acknowledged and greatly appreciated.
ABSTRACT
This report identifies and documents pavement preservation research needs. The primary sources of information used to develop this report include a comprehensive survey of State Highway Agency (SHA) practice and a review of recent literature on the topic. SHAs and four Canadian Provinces were asked to provide detailed responses to a 33-question survey; the 35 responses that were received are viewed as an accurate representation of the current state of the practice.
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CHAPTER 1. INTRODUCTION
INTRODUCTION
The pavement preservation philosophy applies traditional engineering-based analytical tools
to the sensible management of a transportation agency’s pavement infrastructure. A key
component of the philosophy is that good roads cost less: while they are in good condition good
roads cost less for the owner agency to maintain and they also cost less to the traveling public
that operates their vehicles on them. In addition to saving money, pavement preservation
practices―which are intended to maintain good roads in good condition―extend a pavement’s
service life and provide smoother, safer, and more reliable transportation networks. Pavement
preservation is also an important part of an asset management program, in which similar
engineering-based analytical tools and decision-making processes are applied to other elements
of the infrastructure for which a transportation agency is responsible.
In the past 5 years or so, both practitioners and researchers have focused attention on
pavement preservation programs. During this period, there have been several loosely
coordinated initiatives to further develop the tools used in a pavement preservation program.
These initiatives include the following:
The AASHTO Lead States Team for Pavement Preservation issued a report, Research
Protocols for Pavement Preservation in 1999, in which one of the goals of the Lead
States Team is “to establish the need for pavement preservation research…”
The TRB Maintenance Research Master Planning Workshop held in January 2000,
developed a 3-, 5-, and 10-year master plan of maintenance research needs. Included in
the plan were recommendations for applied research of specific thin surface treatments.
1
A workshop sponsored by the FHWA, the Foundation for Pavement Preservation (FP2),
and several State Highway Agencies (SHAs) in June 2001, produced a joint report,
Pavement Preservation Research Problem Statements. That workshop resulted in the
development of 22 research problem statements and more than 50 research topic area
needs. Further policy guidance was determined necessary for effective pavement
preservation.
A Research and Development Workshop was sponsored by the Foundation for Pavement
Preservation and the FHWA in February 2003. Participants included Federal, state,
industry, and other stakeholders. The workshop clarified research needs, explored
potential funding sources, and amplified the need for development of a strategic plan for
pavement preservation.
The TRB Pavement Maintenance Committee (A3C05) and the AASHTO Subcommittee
on Maintenance routinely propose research topics for consideration and funding by
NCHRP.
A common thread in the initiatives noted above is the implication that further fundamental
and applied research is needed on the topic of pavement preservation. Even as many SHAs are
in the process of implementing pavement preservation programs, guidance on treatment selection
procedures, design techniques, quality control/quality acceptance practices, and other
components of pavement preservation programs is still required. A national effort to assemble
and summarize currently available information on pavement preservation, and to clearly outline
research plans to address these needs, will not only help to provide the needed guidance, but also
help to ensure that the industry’s best practices are uniformly available to all agencies.
2
PROJECT OBJECTIVE
The objective of this project is to identify and document pavement preservation research
needs. It is expected that the results will be used to further refine research and funding needs in
this area, to develop proposed research project scopes, and to establish priorities for competing
research interests.
PROJECT APPROACH
Two approaches to information collection were used to develop an understanding of the state
of the practice in pavement preservation-related research. One part of the effort involved
conducting a literature search to assess the types of research activities that were recently funded
or are currently being funded by different interested organizations (i.e., state highway agencies,
local agencies, FHWA, LTPP, FP2, various international organizations, and different industry
organizations). The other, major thrust of this project was to create and distribute a detailed
questionnaire on pavement preservation practices. The questionnaire was distributed
electronically to all 50 State highway agencies and 4 Canadian provinces; the responses from 33
states and 2 provinces are compiled into a comprehensive summary of the current status of
ongoing pavement preservation activities (i.e., implementation status, ongoing preventive
maintenance research, treatment selection and timing practices, SHA experiences [successes and
failures], and so on), and are referred to throughout this report. The results of the literature
review and survey responses were then used to assess current practice and to develop prioritized
recommendations for future research needs.
3
REPORT OVERVIEW
The remainder of this report is organized as follows:
Chapter 2—Overview of Pavement Preservation Practices.
Chapter 3—Summary of Recent Pavement Preservation Research.
Chapter 4—Pavement Preservation Research Needs.
Chapter 5—Recommendations for Future Research.
Appendix A—2004 Pavement Preservation Questionnaire.
Appendix B—2004 Pavement Preservation Questionnaire Results.
4
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CHAPTER 2. OVERVIEW OF PAVEMENT PRESERVATION PRACTICES
INTRODUCTION
Pavement preservation is an increasingly important component of highway agencies’ efforts
to manage their pavements. There are several forces that contribute to this phenomenon,
including the following:
Reductions in force: agencies have experienced reductions in staff, as a result of factors
that include overall budget reductions and a change in priorities.
Continued growth in pavement management: increased attention to managing pavements
throughout their life, with an emphasis on pavement performance and cost effectiveness.
Greater attention to pavement maintenance and its role in overall pavement performance,
starting with the Strategic Highway Research Program (SHRP) projects on maintenance
performance (SPS-3 and SPS-4), maintenance materials and methods (H-105 and H-106),
and maintenance effectiveness.
In some instances the practice and the pace of implementation of pavement preservation is
outstripping the information that is needed and available to support pavement preservation
practices.
This chapter provides an overview of pavement preservation. First, definitions of some of
the recurring terms are provided as a backdrop to their use in this report. Next, a general
description of the data collection effort undertaken for this project is included. Finally, the
chapter concludes with a summary of previous overviews of the state of pavement preservation
practice and some of the findings from the 2004 data collection effort.
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PAVEMENT PRESERVATION DEFINITIONS
An informed discussion of pavement preservation must be built upon a shared lexicon. The
most commonly used terms in this report are “pavement preservation” and “preventive
maintenance.” For this report, widely used definitions for both terms have been adopted.
However, in examining the work of other agencies and researchers it is important to remember
that these terms do not have a universally accepted meaning.
As the following definition suggests, pavement preservation is an over-arching concept:
Pavement Preservation—A program employing a network level, long-
term strategy that enhances functional pavement performance by using an
integrated, cost-effective set of practices that extend pavement life,
improve safety, and meet motorist expectations.
Pavement preservation includes typical routine maintenance activities, such as drainage ditch
blading, shoulder grading, and annual operations such as crack filling or patching. It also
includes corrective maintenance, which is work performed once a distress becomes severe
enough to warrant repair, such as pothole filling or spall repair. Many pavement preservation
programs also include minor rehabilitation, which may address specific structural improvements
to extend pavement life while the pavement is still in good condition (e.g., load transfer
restoration and thin overlays).
Preventive maintenance is a key component of an overall pavement preservation program.
Sometimes referred to informally as “keeping good roads good,” the following definition
summarizes the concept of preventive maintenance.
Preventive Maintenance—A planned strategy of cost-effective
treatments applied to an existing roadway system and its appurtenances
7
that preserves the system, retards future deterioration, and maintains or
improves the functional condition of the system (without increasing the
structural capacity).
This definition incorporates several emphases, including planning (as opposed to reactive
maintenance), preservation (rather than system enhancement), and functional performance. To
many agencies, preventive maintenance spans a range of treatments from the corrective or
reactive to the rehabilitative. As such, it may include certain types of surface recycling, thin
overlays, and other treatments that arguably add structural capacity while extending the life of
the pavement.
A more specific definition of a preventive maintenance treatment is the following:
Preventive Maintenance Treatment—Any individual maintenance
treatment that is used in a preventive manner (i.e., applied to a pavement
in relatively good condition), while not adding any structural capacity to
the pavement.
Examples of preventive maintenance treatments include crack sealing and joint resealing, fog
seals, chip seals, slurry seals, microsurfacing, dowel bar retrofitting, diamond grinding, and so
on. An important aspect of this definition of preventive maintenance treatments is that many
treatments can be defined as “preventive,” because the defining characteristic of a preventive
maintenance treatment is that it is used in a preventive manner. Put another way, “preventive
maintenance treatment” is defined by the application in which it is used and not by the use of the
treatment itself.
8
Adding to the potential confusion associated with the absence of widely accepted
terminology, the terms “pavement preservation” and “preventive maintenance” are often used
interchangeably, and this is likely to continue as agencies develop and refine their programs and
practices. However, an effort is made to adhere to the definitions presented above in the data
collection effort and reporting associated with this research.
PAVEMENT PRESERVATION QUESTIONNAIRE
As noted in the first chapter, a key part of the data collection effort for this project was the
development, distribution, and analysis of the results from a 33-question survey. The
questionnaire was developed to assess current practice, and includes many questions about the
programs, treatments, and research that are underway. It was also designed to provide current,
updated responses to previous surveys. As such, many of the questions are similar to those
found in previous efforts. A copy of the survey is found in Appendix A.
In developing this survey, it is readily acknowledged that SHAs are regularly inundated with
questionnaires, and each such onslaught is another unscheduled demand on limited time. The
burden created by these questionnaires can be lessened by the use of short, multiple-choice
questions, and increased by long surveys requiring fill-in-the-blank answers; surveys that require
a lot of time to complete are less likely to be returned. On the other hand, more information is
gleaned from more comprehensive surveys, so that the surveyor is always weighing trade-offs.
The questionnaire developed for this project is 16 pages long, and consists of questions that
either require short answers or making a selection from a list of available responses. Most of the
questions provided opportunity for follow-up explanations or elaborations, substantially
increasing the potential time required to respond. Responding in this format can be fairly simple,
but the level of detail requested could require several hours to provide.
9
In order to reduce the time required to fill out and submit the survey, it was developed as a
macro-driven Microsoft® Word document, incorporating many of the modern day software
controls (e.g., check boxes, drop down list boxes, and so on) available within the program.
Respondents had the option of responding using either traditional means (by selecting or writing
in answers in a “hard” copy), or by completing a digital version and sending in the response by
e-mail. A hard copy of the questionnaire was first distributed to attendees at the Annual Meeting
of the AASHTO Highway Committee’s Subcommittee on Maintenance (SOM) in Bismarck,
North Dakota in July 2004. Subsequently, an electronic version was sent to the rest of the 50
state highway agencies, as well as to 4 Canadian Provinces.
In addition to asking the right questions, one of the keys to a successful questionnaire is
getting it into the hands of the right person to respond. In distributing the questionnaire for this
project, the emphasis was not just on getting a returned questionnaire, but on getting good
answers. After the questionnaire was distributed to the maintenance engineers at the SOM
meeting, additional recipients included either the state maintenance engineer or another engineer
who was identified as a pavement preservation contact person by the FHWA’s Pavement
Preservation Expert Task Group. In several cases, the recipient forwarded the questionnaire to
someone within the agency identified as more qualified to respond. Several of the responding
agencies also provided responses collected from the initial recipient as well as others, such as the
materials engineer, research engineer, or chief engineer. These types of group efforts help to
increase the likelihood that the responses are both comprehensive and reflective of actual
practice throughout the agency.
Ultimately, the respondents consisted of 33 SHAs and 2 Provinces; all subsequent analyses
and discussion of the 35 responses do not distinguish between States and Provinces. While the
10
response rate is not as high as previous surveys, the detail provided by many of the respondents
indicates that a great deal of time and thought went into providing comprehensive responses. An
extensive summary of the survey responses, including limited analysis, is available in
Appendix B.
SUMMARY OF PREVIOUS SURVEYS OF SHA PAVEMENT PRESERVATION PRACTICES
As a first step in identifying pavement preservation needs, it is important to understand
current SHA pavement preservation practices. In the past decade there have been a number of
nationwide surveys of pavement preservation or preventive maintenance practice. These include
the following:
In 1996, a survey on preventive maintenance needs was sent to 50 states, Washington, D.C.,
and Puerto Rico (1). The 45 responding agencies indicate a range of experience, interests, and
research needs, as summarized below:
Are you interested in developing a preventive maintenance program?
28 agencies responded yes and 15 responded no.
Do you need assistance in getting top management to buy in?
16 agencies responded yes and 17 responded no.
Do you need technical assistance for specific treatments?
16 agencies responded yes and 17 responded no.
Do you need assistance in refining the decision-making process for determining the size
of preventive maintenance program needed?
18 agencies responded yes and 13 responded no.
11
Do you need assistance in refining the decision process for determining which type of
treatment is needed and/or for determining when treatments should be placed?
22 agencies responded yes and 10 responded no.
This last question generated several additional comments, including:
Need a decision tree for when to place preventive maintenance treatment.
Optimal timing would be beneficial.
Would like to better define when [treatments should be applied].
When treatments should be placed is a real need.
A follow-up to the 1997 survey on pavement preservation practices was circulated in October
1999 by the AASHTO Lead States Team on Pavement Preservation (2). The following
summarizes the responses of the 40 state highway agencies and Puerto Rico:
36 agencies have established programs and two are in the process of developing
programs.
All 41 agencies use preventive treatments [not necessarily treatments in preventive
applications].
17 respondents said that their programs have existed for at least 10 years.
31 agencies reported that their pavement preservation programs are integrated with
pavement management systems, while such integration is in the beginning or informal
stages in three agencies.
• 20 agencies characterize the administration of their programs as centralized.
12
The 1999 survey did not focus on research needs and therefore did not specifically identify
any. In the course of responding to questions about the status of their programs, the following
comments are extracted:
Need specific guidelines about the integration of pavement preservation with pavement
management systems.
Several agencies report that they are working on preventive maintenance guidelines.
More than half of the respondents said that they have test sections. Reported experience
ranged from using the SPS-3 sections in their state to constructing test sections to
evaluate treatment performance and effectiveness.
The results have been instrumental in both defining current agency practices as well as
summarizing pavement needs.
At least two other, more informal surveys have been performed since the last Lead States
Team on Pavement Preservation survey in 1999. In January 2002, the Colorado Department of
Transportation distributed a four-question survey on pavement management practices to the
Materials Engineer in every state. The questions concerned the size of the agency’s pavement
network, the annual surface treatment budget, the preventive maintenance budget, and the
method used to allocate funds. Twenty-eight responses were received, and the average of those
responses is presented below (3):
The responding agencies are responsible for an average of 36,329 centerline miles.
They spend an average of $164.4 million annually on surface treatments, or
$3,516/centerline-km ($5,658/centerline-mile).
13
The average annual preventive maintenance budget is $51.8 million, or $695/centerline-
mile ($1,119/centerline-mile).
In 2003, at the request of the FHWA’s Pavement Preservation Expert Task Group, the
Foundation for Pavement Preservation supervised the distribution of a survey to assess the
current level of research being conducted in seven broad research areas. That survey generated
responses from 49 states and 4 provinces, and the findings are summarized as follows:
Two states either were not doing any research or had no interest in research.
Twelve states had an interest, but were not currently doing any research.
Of the states doing research, most was in the areas of materials and mix design.
There was the least amount of active research taking place on training.
2004 SURVEY RESULTS
The previously cited surveys were performed recently enough that those responses should be
considered in assessing the current state of the practice in pavement preservation. The survey
that was developed and distributed as part of this project builds on those previous studies, and is
the primary resource that is used in the rest of this chapter to assess current practices. Starting
with Question 4 in the 2004 survey, many questions directly address the agency’s pavement
preservation practices; this section discusses the responses related to the status of programs.
Question 4 asks “Does your agency currently have a pavement preservation program in
place?” Of the 35 respondents, 30 stated that they had a pavement preservation program in
place. Of the 30 positive responses, in their additional comments two agencies indicate that their
programs are actually under development and one said that their program was more pavement
maintenance than pavement preservation. Question 7 asks “If your agency does not currently
14
have a program, is there interest in creating and implementing one?” This question received 9
“yes” responses, including the 5 who responded “no” to Question 4. Considering the responses
to Questions 4 and 7 together, it is more appropriate to conclude that 26 out of the 35
respondents actually have a pavement preservation program (the 30 identified in Question 4 and
the 4 additional “yes” responses to Question 7).
Positive responses to Question 4 were directed to Question 5, which asks for more detail
about the programs. Question 5a asks about the formality of the programs in order to obtain
more detail about the different types of programs: this question specifies that an informal
program is one in which pavement preservation practices are being followed at the local level,
but not necessarily as part of a defined program or mandated practice. Of the 30 agencies that
said they had a program in Question 4, 8 said that their programs were “informal,” 18 said that
their programs were “formal” (i.e., guidelines or policies dictate the program’s practices and
dedicated funding is used to pay for preventive maintenance treatments), and 4 said that they had
formal programs, but no dedicated funds supported them.
Question 5b asks how long the current pavement preservation programs have been in place.
Nineteen of the 29 respondents to this question said that their programs are less than 10 years
old, and the rest said that theirs were older than 10 years. Pavement preservation programs are
clearly relatively new. Figure 1 shows the distribution of the reported programs’ ages, and an
additional breakdown is shown in table B-8 (in appendix B). Several of the programs date back
to the mid- to late 1980s, there are a few that were created in the early 1990s, and at least 9 were
formed in the 2000s. While it seems appropriate, therefore, to characterize the majority of these
programs as fairly new initiatives, 20 of 31 respondents (table B-9 in appendix B) referred to
their own programs as either “well established” or “moderately established.”
0
2
4
6
8
10
12
<1 year 1 to 3 years 3 to 10 years >10 years
Age of In-Place Pavement Preservation Programs (As of 2004)
Num
ber o
f Age
ncie
s
Figure 1. Distribution of the ages of in-place pavement preservation programs (as of 2004).
Question 5c seeks further insight into the characteristics of existing pavement preservation
programs. It asks respondents to describe the maturity of their programs, ranging from “well
established” (with many preventive maintenance treatments placed and performance being
monitored) to “just beginning.” Six of the 31 responding agencies indicated that they are either
in the early stages or just beginning their programs; the other 25 have programs that range from
having placed a few projects to having placed many projects for a number of years. In the
additional comments provided for Question 5c, two more agencies suggest that in the past their
programs have primarily consisted of the use of preventive maintenance treatments (not
necessarily in preventive applications).
Where Question 5a asks about dedicated funding, it does not solely address this issue.
Question 11 asks “Does your agency have a dedicated budget for a pavement preservation
15
program?” Slightly more than half responded that they did (19 of 35). The second part of the
question asked for the amount of funds dedicated to pavement preservation. Figure 2 illustrates
the distribution of the responses. Most of the responding agencies fund their programs with less
than $50 million annually; however, six agencies reported programs with more than $75 million
in annual funding.
0
1
2
3
4
5
6
7
8
<$10 mil $10 to $25 mil $25 to $50 mil $50 to $75 mil >$75 mil
Dedicated Funding for 2004
Num
ber o
f Age
ncie
s
Figure 2. Amount of dedicated agency funding for pavement preservation in 2004.
Successful pavement preservation programs are built with dedicated funding. In the absence
of funds that are set aside for specific use in a pavement preservation application, it is much
more likely that pavement funding is directed toward rehabilitation or reconstruction projects.
From the provided responses it was not possible to discern how much of the pavement
preservations budgets were allocated to preventive maintenance.
16
17
It is also difficult to sustain pavement preservation practices at a local level without the
formal support of the agency. Such support might consist of printed guidelines on project
selection, treatment selection, treatment performance, and so on. The responses to the different
questions about the details of pavement preservation practices suggest that the number of
agencies with formal pavement preservation programs is somewhere between the 18 responses
identified in Question 5a and the 30 responses identified in Question 4.
Question 12 asks for information about how funding is administered and distributed
throughout the agency. Approaches that have been used to manage pavement preservation
programs include administering the program from the central office (such as in Materials or
Maintenance) or having a decentralized program (such as administering the program at the
District or Region level). Eleven of 21 respondents to Question 12 indicate that their agency’s
programs are centrally administered, 3 report that they are decentralized, and 7 say that they are a
combination of the two.
Pavement preservation programs are being used in a broad range of applications. Question
13 asks “On what facility types does your agency currently apply preventive maintenance
treatments?” and participants were requested to check all applicable options from the choices of
freeways, arterials, collectors, and local roads in both rural and urban settings. Figure 3 presents
the distribution of responses, and shows that there is a slight preference for the use of such
treatments on rural roads. Interestingly, the responses indicate that these treatments are being
used more on higher volume roads than on lower volume roads.
0
5
10
15
20
25
30
35
Freeway(>=30,000 ADT)
Arterial(12,000 to 40,000 ADT)
Collector Road(2,000 to 12,000 ADT)
Local Road(<= 2,000 ADT)
Roadway Classification
Num
ber o
f Age
ncie
s
RuralUrban
Figure 3. Distribution of roadway classifications on which
agencies apply preventive maintenance treatments.
One of the most important measures of a successful preventive maintenance program is that
treatments are being applied to pavements in good condition. When this occurs, it can be
inferred that the agency has committed to keeping good roads in good condition, has adopted the
philosophy of pavement preservation, and has overcome the internal and external barriers to this
approach. In fact, at the start of the questionnaire a preventive maintenance treatment is defined
as a “maintenance activity that is used in a preventive manner (i.e., applied to a pavement in
relatively good condition).” Question 14 asks “Approximately what percent of your preventive
maintenance projects are placed on pavements in each of the following condition categories
[very good, good, fair, poor, and very poor]?” No further definitions of those condition
categories are provided with the question, and respondents were asked to assign a percentage of
their preventive maintenance treatments to each category so that the total equals 100 percent.
18
The average of the responses to Question 14 is shown in figure 4. Most of the responses fell
in the good and fair categories, but there are also some surprising responses: one agency reports
that 60 percent of their treatments are placed on pavements in very good condition, while 9
agencies report placing at least 30 percent of their preventive maintenance treatments on
pavements in poor or very poor condition.
0
5
10
15
20
25
30
35
40
45
50
Very Good Good Fair Poor Very Poor
Pavement Condition
Perc
enta
ge o
f PM
Pro
ject
s A
pplie
d To
Pa
vem
ents
In D
iffer
ent C
ondi
tion
Cat
egor
ies
(Ave
rage
s of
All
Res
pons
es)
Figure 4. Distribution of the percentage of preventive maintenance projects placed on
pavements in different condition categories (averages of all agency responses).
Questions 15 through 22 seek more details about preventive maintenance practices. The
questions and a summary of the answers are provided below.
Question 15: Does your agency typically apply more than one preventive maintenance
treatment before rehabilitation? There are 24 “yes” and 6 “no” responses. It is believed that
more mature pavement preservation programs are likely to use more than one treatment over the
life of a pavement in order to cost effectively preserve it. The 24 positive responses are
19
20
consistent with the number of agencies that are identified to have programs that are fairly formal
and mature.
Question 16: For what purposes do you apply preventive maintenance treatments?
(respondents were asked to select all appropriate responses; the responses are summarized below
in order of frequency).
Reduce rate of deterioration: 33.
Seal surface: 30.
Reduce water infiltration: 28.
Increase friction: 27.
Increase smoothness: 21.
Noise abatement: 3.
Fill ruts: 2.
Lane delineation: 1.
Blade patches: 1.
Aesthetics: 1.
The most responses an answer could receive is 35, so from the selections indicated above it is
clear that most of the agencies using preventive maintenance treatments are doing so to extend
the life of the pavement through sealing and controlling moisture infiltration. The other primary
uses of these treatments are to improve safety and ride (increase friction and increase
smoothness).
Question 17: Which treatments are applied in a preventive manner? (Respondents were
asked to select all applicable treatments, and to indicate whether the treatment has been used in
the past, is currently being used, is planned to be used, or there is interest in using it). The
21
detailed results are presented in Table B-24 in appendix B. The following is a summary of the
most frequently used treatments:
Diamond grinding: 30.
Crack sealing: 28.
Single chip seal: 28.
Full-depth concrete repair: 28.
Thin HMA overlay: 27.
Single course microsurfacing: 27.
Concrete joint resealing: 27.
Concrete crack sealing: 27.
Partial-depth concrete repair: 27.
Paver-placed surface seal: 25.
Overband crack seal: 24.
Polymer-modified chip seal: 23.
Mill and HMA overlay: 23.
Dowel bar retrofit: 22.
Profile milling: 21.
Multiple course chip seal: 18.
Underdrain outlet repair and cleaning: 18.
Hot-in-place recycling: 17.
Cold-in place recycling: 17.
Multiple course microsurfacing: 17.
Slurry seal: 17.
Fog seal: 16.
22
These represent the treatments that are used by approximately half or more of the respondents,
and show that most of the treatments that are associated with preventive maintenance are widely
used.
Several questions address treatment selection. Question 18 asks about the method used by
agencies to select a preventive maintenance treatment. The most widely used approach is
engineering judgment (28), followed by a selection matrix based on distress types and
severities/extents (21), in-house guidelines (19), a preset schedule of times (12), and a
cost/benefit analysis (7). Engineering judgment should be associated with less formal or mature
programs, while the application of selection tools (such as matrices or decision trees), detailed
analyses, or published guidelines should be associated with more formal and mature programs.
Similarly, Question 19 asks if treatment selection is tied to the agency’s pavement management
system, and elicited 23 out of 33 positive responses (broken out as follows: 7 were completely
integrated, 7 were currently in the process of integrating the two, and 8 were using in-house
guidelines). When pavement preservation and pavement management are integrated it suggests a
program that is fairly mature, as integration requires the capability of monitoring treatment
location and placement, as well as treated pavement performance over time. The use of a
pavement management system to select or recommend preventive maintenance treatments
suggests an additional level of sophistication.
Question 20 asks about the method used to select the timing. The most common technique
for treatment selection is based on the appearance of minimal distress (15); 12 respondents said
that preventive maintenance treatments are placed when distress reaches a medium severity level
and 5 said that they are placed according to a predetermined timetable. As these terms are not
defined, no firm conclusions should be drawn from the responses. However, the responses seem
23
consistent with those provided for Question 14, which asked respondents to identify the percent
of preventive maintenance projects applied on pavements of different condition levels.
Question 21 asks if the respondent’s agency uses a pavement management system to
optimize the timing of preventive maintenance treatments; 15 respondents said “yes” while 18
said “no.” While no specifics are sought, optimization implies that information about the cost
and performance of various treatments under different conditions is fairly well known. It further
implies that fairly sophisticated analytical tools (cost-benefit analyses, for example) are used to
select among different treatments. The use of an optimization approach and a management
system suggest that the positive answers are being given by agencies with comparatively formal
and mature preservation programs.
SUMMARY
There is a wide range of pavement preservation practices in use today among highway
agencies. A common approach to determining pavement preservation practice has been to
distribute a questionnaire to SHAs and compile and report the results. An important part of this
project to identify and document pavement preservation research needs is to document the
current state of the practice. Accordingly, a survey was prepared and distributed to SHAs and
Provinces. In the past 5 years, at least two such formal surveys were previously distributed, and
at least several more informal surveys have sought similar information.
Relevant information from those previous surveys, as well as the responses generated by the
survey distributed for this study, provide a good indication of the current state of the practice. It
is clear that pavement preservation programs are relatively new, as there are very few state
highway agencies that have more than 10 years of experience with formal, sophisticated
programs. Practices vary among agencies, but the more sophisticated pavement preservation
24
programs are formal and have dedicated funding, are integrated with pavement management
programs, and include tools for treatment selection. While at least half of the 35 responding
agencies are at this point, there is very widespread interest in improving these programs.
This interest is documented in responses to questions about interest in ongoing research
performed by others, in responses to questions about the agencies’ own research activities, and in
a literature review of recently completed or ongoing research. These topics are explored further
in chapter 3.
25
CHAPTER 3. SUMMARY OF RECENT PAVEMENT PRESERVATION RESEARCH
INTRODUCTION
As noted in chapter 1, within SHAs there is a growing shift toward pavement preservation
programs. Inasmuch as the successful use of preventive maintenance treatments call for a much
more informed approach to project selection and treatment selection, agencies engaged in
pavement preservation practices are likely considering questions such as the following:
Which treatments are best suited for our roadways?
When is the optimal time to apply those treatments?
What are the best construction techniques to use when applying our selected treatments?
Are we using the best materials available, or the materials most suited for our
location/climate?
What pitfalls should we avoid when applying treatments?
How do we measure the success of the treatments that we apply?
What other agencies have used similar treatments and what type of success have they had
with them?
One of the best sources of answers is to tap into the past experiences of others who have had
similar goals and encountered similar obstacles. Reviewing the past pavement preservation-
related research (both at the national and local agency level) not only generates different ideas
that may be incorporated into the developing pavement preservation program, but also helps to
26
avoid potential pitfalls during the process. This chapter provides a summary of the recent and
ongoing pavement preservation-related research.
SUMMARY OF RECENT PAVEMENT PRESERVATION-RELATED RESEARCH
As a first step in identifying recently completed and ongoing pavement preservation research,
a literature search was completed in which recent pavement preservation–related research was
reviewed. The goal was to identify and summarize recent and ongoing research that might be of
interest or use to other agencies. The results can be organized into the following general
categories:
Treatment selection procedures/guidelines.
Treatment timing.
Innovative materials and construction techniques.
Materials selection and mix design.
Treatment performance.
Specifications.
While this project’s survey was specifically designed to ask questions related to these different
research topics to assess the SHA research experience in these different areas, much of the
information about ongoing research was gleaned from the Transportation Research Board’s
(TRB) Research-in-Progress web site (www.rip.trb.org), as well as from many SHA web sites.
Using the results of the literature search, the remainder of this chapter contains a summary of
the recent national and SHA pavement preservation-related research activities organized into the
above mentioned categories.
27
Treatment Selection Procedures/Guidelines
While many agencies are using preventive maintenance treatments, a key component of a
successful program is determining how to select the most appropriate treatment for a given
pavement. Current practice varies from choosing a treatment based on past experience
(engineering judgment) to using comprehensive computer programs that incorporate data
analysis and modeling procedures (4).
General Guidelines for Treatment Usage
Many agencies have drafted in-house guidelines that define the appropriate use of the
available preventive maintenance treatments. The guidelines provide information about a
treatment’s use so that engineering judgment may be used to select the appropriate treatment. A
number of examples of in-house guidelines were identified in the literature search. Specific
examples of treatment selection guidelines include the following:
Iowa Department of Transportation—In 1997, the Iowa DOT began a project with the
objective of developing guidelines for using thin maintenance surfaces (TMS) on
asphaltic concrete and bituminous roads (5). The TMS that were considered included
seal coats (i.e., single chip seals, sand seals, and double chip seals), slurry seals, and
microsurfacing. Qualitative guidelines were developed to provide guidance on which
roads are good candidates for TMS, when TMS should be placed, and what type of TMS
should be selected (5). These interim guidelines were developed specifically for Iowa
weather, traffic conditions, road-user expectations, and transportation official
expectations.
In Phase two of the Iowa DOT research study, TMS quantitative guidelines were
developed to limit the variation in application between users (6). Allowable distress
28
quantities were selected by considering an appropriate surface condition index (SCI) for
given treatments, traffic levels, and distresses. The new guidelines, based on the
pavement condition index (PCI) rating system developed by the U.S. Corps of Engineers,
were developed using condition data collected from four test sections placed over 3 years.
Michigan Department of Transportation (MDOT)—In 1999, MDOT published
preventive maintenance treatment guidelines as part of its Capital Preventive
Maintenance Manual (7). This manual contains specific treatment guidelines associated
with eight treatments for flexible and composite pavements, and eight available
treatments associated with rigid pavements. For each available treatment included in the
MDOT capital preventive maintenance program, the guidelines define the following
types of treatment-related information:
– Treatment description.
– Treatment purpose.
– Acceptable pavement condition-related characteristics.
– Required pavement surface preparation.
– Expected performance of the treatment.
– Treatment limitations.
Texas Department of Transportation (TxDOT)—In 1999, Smith and Beatty published
a paper that included guidelines for microsurfacing that were developed while working
on a research study for the Texas Department of Transportation (TxDOT) (8). The
guidelines are based on information collected from published literature, personal
experienced in using microsurfacing, TxDOT personnel, industry personnel, and the
project staff’s experience developed during the project. Specifically, the guidelines
29
outline applications in which microsurfacing would be a beneficial treatment alternative,
thickness guidelines, and opening-to-traffic guidelines.
Ohio Department of Transportation—A fact sheet published by FHWA in 2001
describes Ohio’s Pavement Preventive Maintenance Guidelines. Available preventive
maintenance approved for use in the current specifications include crack sealing, chip
seals, microsurfacing, concrete pavement restoration, thin hot-mix asphalt inlays and
overlays, and drainage preservation. For each treatment, the guidelines discuss (9):
– Description and purpose.
– Pavement condition considerations.
– Traffic constraints.
– Design considerations.
– Seasonal construction limitations.
– Unit cost for estimating.
– Anticipated performance and service life.
Decision Trees and Matrices
Decision trees incorporate a set of criteria for identifying a particular treatment through the
use of “branches” (10). Each branch represents a specific set of conditions (in terms of factors
such as pavement type, observed distress type and level, traffic volume, etc.) that ultimately
leads to the identification of a particular treatment.
Decision matrices are very similar to decision trees in the sense that each relies on a set of
rules or criteria to arrive at an appropriate maintenance or rehabilitation treatment. The major
difference is that decision trees provide a more systematic graphical approach to the selection
30
process, while matrices are tabular. A summary of benefits and limitations of using decision
trees and matrices is shown in table 1.
Table 1. Benefits and limitations of using decision trees and matrices (10).
BENEFITS
Makes use of existing experience.
Works well for local conditions.
Good as a project-level tool. LIMITATIONS
Not always transferable from agency to agency.
Limits innovation or use of new treatments.
Hard to incorporate all factors which are important (e.g., competing projects, functional classification, remaining life).
Difficult to develop matrix that can incorporate multiple pavement distress types (i.e., does not always address the actual distress conditions).
Does not include more comprehensive evaluation of various feasible alternatives and LCC analysis to determine the most cost effective strategy.
Not good for network evaluation.
The literature review also shows that there has been recent work on the development of
treatment selection decision trees and matrices. The following summarizes the details of these
efforts:
A recent publication by Wei and Tighe discussed the efforts of developing preventive
maintenance decision trees based on cost-effective analyses for the road network in
Ontario, Canada (11). The primary goal of this research was to compare the cost
effectiveness of 15 different HMA preventive maintenance treatments as used under the
climatic and traffic conditions specific to the Ontario road network. The research method
used for this project was based on determining the cost-effectiveness for each treatment
or strategy as the area underneath the performance curve divided by the life-cycle cost of
31
each strategy. Decision trees were then developed for each pavement functional class in
the Ontario road network based on an analysis of the pavement data provided by the
Ministry of Transportation of Ontario (MTO).
In 2003, the Foundation for Pavement Preservation (FP2) published “A Pocket Guide to
Asphalt Pavement Preservation” in partnership with the Federal Highway Administration
(FHWA) (12). This FP2 pamphlet contains a matrix that provides advice on when to use
14 different preventive maintenance treatments on asphalt pavements. The guidance is
primarily based on the different types of distress present, their extent, and their severity.
New Mexico has developed a Performance and Planning Matrix, which is currently a
guide used in aiding design engineers, operations engineers, and management in making
decisions (13). There are three parts to the New Mexico Matrix: the Performance and
Planning matrix, the Decision Table, and the Condition Assessment Table. The
combination of the three establishes guidelines for the selection of roadway projects for
both construction and maintenance programs.
Output From A Pavement Management System
As pavement preservation has moved to the forefront of agency practice, a topic of growing
interest is integrating preventive maintenance into pavement management systems so that the
pavement management system may be used to optimize the application of preventive
maintenance treatments in terms of selecting the best preventive maintenance treatment type and
timing. Based on observations made working with different agencies across the country, Peshkin
observed that “integration with pavement management is essential if agencies are going to be
able to show that their pavement preservation programs are effective” (14). In a 2003 report, the
authors note that “integrating pavement preservation with pavement management is imperative”
32
to obtaining a successful preventive maintenance program (15). By using an integrated PMS, a
manager can select the proper proportion of preventive maintenance, corrective maintenance,
rehabilitation, and reconstruction that optimizes available dollars and extends the service life of
the pavements within the system (16).
There are a number of papers and reports that not only describe the current movement toward
integrating preventive maintenance and pavement management, but also document current
efforts by SHAs. There are three primary approaches that can be used to integrate preventive
maintenance treatments into a pavement management system (17). These consist of the
following:
Provide recommendations for preventive maintenance candidate sections. A simple
approach is to use pavement management system to analyze the rehabilitation and
reconstruction needs of a network, and any pavement sections that are not candidates for
these types of treatments are automatically considered to be candidates for preventive
maintenance. Although this approach is easy to implement because it requires no
changes to the pavement management models, it provides limited support for analyzing
the impacts associated with the use of preventive maintenance treatments.
Incorporate a single treatment into the pavement management analysis models that
represents a variety of preventive maintenance treatments. This is a more sophisticated
approach that still is relatively simple to implement and does not require very
sophisticated analysis tools to use; however, the performance rules and cost models that
are used to analyze the preventive maintenance treatments tend to be averages that
represent a broad range of possible treatments. This approach is better than the first
33
approach, but does not provide a specific recommendation for the type of treatment that
should be used.
Fully incorporate preventive maintenance treatments into the current system. The most
sophisticated approach is to define specific preventive maintenance treatments into the
pavement management system and to develop performance models, treatment rules, cost
functions, and impact models for each defined treatment. This approach requires the
most effort to establish, but provides the greatest level of support for the preventive
maintenance program.
A large number of agencies are recognizing the value of incorporating preventive
maintenance treatments into an established PMS, and many are making progress toward
integration. Specific efforts being made by agencies to complete this integration of pavement
maintenance and pavement management are documented below (presented in alphabetical order
by agency). This has also been the topic of at least one recent TRB session.
Arizona Department of Transportation. In 2004, the Arizona Department of
Transportation (ADOT) completed research focusing on enhancing its existing PMS so that the
benefits of preventive maintenance activities may be tracked. Previously, ADOT did not have a
process to objectively measure the benefit (e.g., improved pavement performance) of preventive
maintenance treatments. This study (titled Enhance the Pavement Management System So That
It Can Determine Preventive Maintenance Strategy Effectiveness) resulted in updates to the
pavement management system that allow cost effectiveness to be determined and used in the
development of pavement preservation strategies.
34
California Department of Transportation. In 1995, the California Department of
Transportation (Caltrans) made a commitment to transition away from using a “worst first”
maintenance strategy by beginning to implement a Pavement Preservation Program. As of 2001,
Caltrans had completed the first phase of integrating its preventive maintenance program into the
existing pavement management system (PMS) (18). Currently, Caltrans’ PMS works in concert
with Caltrans’ GIS to provide management and districts the data needed to identify the pavement
needs of the statewide and on a district-by-district basis. In a 2001 report, Pool discusses how
the PMS uses the data collected from the pavement condition surveys to assist Caltrans and
districts in creating Caltrans strategic 10-Year Work Plan (18).
Kansas Department of Transportation. The Kansas Department of Transportation
(KDOT) uses a PMS to track pavement condition annually and to provide measures for
Performance-based Budgeting and Asset Management, but most importantly, KDOT uses the
system to help program reconstruction, rehabilitation, and maintenance of pavements (19). As a
first cut, approximately 95 percent of the project locations are selected by the PMS and a
treatment is recommended. Next, the District and Headquarters personnel select a treatment to
be used based on observations and engineering judgment. In the final analysis, the PMS
treatment recommendation is used approximately 50 percent of the time. Because KDOT has a
way to implement a PMS that supports timely application of preventive maintenance and other
rehabilitation and reconstruction activities, the condition of Kansas’ highway system has
substantially improved (19).
Maryland State Highway Administration (MDSHA). In recent years, the Maryland State
Highway Administration (MDSHA) has begun using pavement management tools to prepare
their annual system preservation program. The project selection consists of a two-step process in
which the first step involves developing strategies to meet a defined objective such as
35
maximizing condition or minimizing costs (20). Once applied, the strategies provide guidance
on how to invest in the network (e.g., the strategy may identify that 100 lane-km [62 lane-m] of
pavement in fair condition should be resurfaced) (20). The final step of the process is for each
district to select individual projects that collectively match up with the results of the applied
strategy. Overall, these tools have allowed MDSHA to apply multiple hypothetical funding
strategies and evaluate the impact of each on the overall health of the pavement network (20).
Metropolitan Transportation Commission (MTC). The Metropolitan Transportation
Commission (MTC) of the San Francisco Bay Area has been involved in the development,
programming, and modification of pavement management systems (PMS) for more than 15 years
in cities and counties in the Bay area, and more recently for the Association of Oregon Counties
(21). In recent years, the MTC has integrated pavement preservation into their PMS. The
following are the primary lessons that the MTC has learned from their experience of integrating
pavement preservation and PMS:
Incorporating preventive maintenance and a pavement preservation approach into PMS
requires appropriate inventory data, distress survey techniques, treatment selection
methods, prioritization approaches, and impact analysis techniques.
The inventory must include information needed in the decision-support models, including
pavement surface, date of construction, and information on the type of treatments that
have been applied since construction and the dates of those applications.
For use in preventive maintenance and pavement preservation applications, the distress
survey methods must use distress types and severity levels that can help identify those
pavements that are in a condition needing preventive maintenance and those that have
36
deteriorated to a condition for which preventive maintenance would no longer be
effective.
The treatment selection methods must identify sections of pavement that will respond to
preventive maintenance, in addition to sections that need major rehabilitation or
reconstruction.
The prioritization approach must be able to rank preventive maintenance as well as major
rehabilitation or reconstruction; worst-first approaches cannot be used.
The impact analysis must be able to analyze the impact of different approaches over at
least 20 years to show how including preventive maintenance will affect a pavement
program.
Michigan Department of Transportation. Michigan DOT relies on the Road Quality
Forecasting System, which uses current condition data from the PMS to predict future network
conditions at different levels of investment (22). Michigan DOT prescribes treatments according
to pavement condition measures, not by schedules for timely application. The forecasting model
has proved an invaluable tool in the State of Michigan.
Montana Department of Transportation. A 2001 report by Clark summarizes the
Montana DOT experience with integrating pavement management and pavement preservation
(23). The Montana DOT Maintenance Division has been using pavement management to aid in
the selection of pavement preservation treatment selection since 1997 to achieve continuous
pavement improvements. Pavement management is currently used as a decision supporting tool
for preventive maintenance, and not a decision making tool. That is, the process does not restrict
the freedom of managers to innovate in the field of pavement treatment development and does
not limit manager’s choices on project selection.
37
Specifically, the Montana DOT surveys their pavements annually as part of their PMS
program. The collected condition data is analyzed and used to compute a structural capacity
index, alligator cracking index, miscellaneous cracking (transverse and longitudinal cracks and
block cracking) index, and a rut index. In addition, international roughness index (IRI) data is
collected and included in the PMS database. All indices are given equal weight and used in
selecting preventive maintenance projects (24). An annual analysis of the PMS data is used to
generate a 2-year work plan that includes a list of potential preventive maintenance projects and
the types of treatment based on the available preventive maintenance budget. The final
preventive maintenance projects are then selected at the district level from this list of potential
projects.
Pennsylvania Department of Transportation. In Pennsylvania, the selection of pavement
projects, pavement designs, and the type of fixes is decentralized and conducted at the district
level (24). Pavement designs are generally performed at the engineering district level, and the
central office reviews designs, establishes design policy, and provides support to the districts.
However, the two activities are being streamlined by guidelines policies on the selection of
project boundaries and treatment types and by using PMS distress data. Over time, the
streamlining has decreased arbitrary selection of projects and treatment types.
South Dakota Department of Transportation. In 2002, the South Dakota Department of
Transportation sponsored research focusing on advancing the integration of the State’s
preventive maintenance strategies into the existing pavement management system. Specifically,
the objectives of this research study were to (25):
Assess the current pavement condition rating procedures to evaluate the impact
maintenance activities have on the calculation of the various condition indices.
38
Identify trigger values that identify when various maintenance treatments are feasible
candidates to retard pavement deterioration and incorporate those trigger levels into the
PMS.
Develop reset values that can be used in the PMS to indicate the impact of maintenance
treatments on pavement conditions so that the appropriate timing for rehabilitation can be
determined.
Develop guidelines to establish feedback loops between maintenance, construction, and
pavement management so that maintenance and construction activities can be
incorporated into the pavement management analysis.
The study resulted in several recommendations to the South Dakota DOT for their pavement
management system. The study suggested slight changes in definitions of patches and transverse
cracks to improve the distress rating system. The study also pointed out inconsistencies with
transitioning from a visual distress survey to a video survey procedure. Several changes were
recommended for the chip seal triggers. The study also recommended setting higher reset values
for maintenance treatments.
Washington State Department of Transportation. In 2002, the Washington State
Transportation Center (TRAC) at the University of Washington began work on a project that
focused on incorporating maintenance management into the current Washington State PMS. The
results of this research are intended to lead to enhanced preservation and maintenance budget
development scenarios. This research is expected to be completed in 2004.
39
Treatment Timing
In a 2000 article in Public Roads magazine, “Pavement Preservation: Preserving Our
Investment in Highways” Davies and Sorenson emphasize the importance of determining the
optimal timing of preventive maintenance treatments (16):
To determine the optimal timing, performance standards and indices for various treatment
types need to be established through research and the collection of performance data. To be
reliable, these indices must be descriptive of the environment in which the pavement
treatments are to be used. This not only includes existing pavement conditions, climatic
weather, material properties, and traffic loading, but also agency resources and funding
limitations.
Determining the optimal timing for a given treatment requires understanding the treatment’s
purpose, how it will perform given the existing pavement condition, and how it will perform
under the given site conditions such as climate and traffic. The same treatment is expected to
perform differently when applied at different times (or on pavements in varying condition) in the
life of the pavement (26). For example, placing a thin bituminous surfacing (such as a chip seal)
on a new pavement may not increase the pavement’s life at all because once the surfacing wears
off, the pavement may begin to show structural deterioration. Similarly, the same treatment
placed near the end of the pavement’s life would most likely have a minimal effect on pavement
performance, because the condition of the underlying pavement would most likely control the
performance. Therefore, for a given pavement, there is some optimal age or condition (or range
of conditions) where the benefit/cost ratio associated with a chosen treatment is maximized.
Intuitively, it is the age associated with this maximum benefit/cost ratio that is defined as the
optimal timing for the treatment (26).
40
This concept of maximizing the benefit/cost ratio is the basis of the analytical approach
outlined in the NCHRP Report 523, Guide for Optimal Timing of Pavement Preventive
Maintenance Treatment Applications (26). In that study, a methodology was developed to
identify the optimal time to apply a single treatment, based on a simultaneous analysis of the
benefits observed from applying a treatment at a given time, and the cost of the application. The
analytical approach compares the resulting benefits and costs associated with different user-
defined treatment timings in order to select the most effective timing of those analyzed (i.e., that
treatment timing associated with the largest benefit/cost ratio). That study included the
development of a macro-driven Microsoft Excel® analytical tool (OPTime) that is used to
automate and demonstrate the developed methodology.
As Davies and Sorenson (16) state, and as is emphasized in the work documented in NCHRP
Report 523, the determination of optimal timing depends greatly on the preventive maintenance
data collected by a state agency that reflects local conditions (16,26). Recently, a number of
state and national studies are focusing on gathering such treatment performance data so that
questions about treatment performance and timing may be more adequately answered. Examples
of recent or ongoing studies that have the investigation of optimal timing as one of their
objectives include the following:
In 2002, the FP2, the Arizona Department of Transportation, and FHWA began a national
study to research the functionality of spray applied sealers and binders. Since 2002, this
study has overseen the placement of test sections in Arizona, California, Michigan, and
Minnesota, with the first taking place in Arizona in the fall of 2001. The study is
intended to evaluate the effectiveness of sealers, rejuvenators and binders for preserving a
pavement’s service life. Specifically, this study is focusing on ways to determine the
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proper timing of these treatments and effective ways for quantifying their benefit to
pavement performance (27).
A 2003 report, The Effectiveness of Maintenance and Its Impact on Capital Expenditures,
documents a study conducted for the Indiana Department of Transportation in which part
of the project focused on determining the most cost-effective maintenance strategies for
different pavement families in the state of Indiana (28). This study determined these
optimal maintenance strategies by conducting a cost-effectiveness study of data supplied
by the Indiana Department of Transportation.
In 2004, the Colorado Department of Transportation (CDOT) started a research study,
Evaluation of the Performance, Cost-Effectiveness, and Timing of Various Preventive
Measures. Because the selection of a maintenance treatment at the CDOT is currently
based on maintenance personnel experience, guidelines are needed to assist in the
treatment selection process and to determine the appropriate time to apply a preventive
maintenance treatment. The ultimate goal of this study is to develop step-by-step
procedures that show when and where to use specific preventive maintenance treatments.
A recent publication by Wei and Tighe (11) discusses the efforts of developing
preventive maintenance decision trees based on cost-effective analyses for the road
network in Ontario, Canada. While the primary goal of this research was to compare the
cost effectiveness of 15 different HMA preventive maintenance treatments as used under
the climatic and traffic conditions specific to the Ontario road network, the cost
effectiveness analysis approach was also used to estimate the proper timing of preventive
maintenance treatments as well. The general results from this timing analysis found that
for a “low cost level strategy or one-time preventive maintenance treatment per cycle
42
strategy,” the most appropriate timing was at the middle of the rehabilitation cycle; for a
“medium cost level strategy or two-time preventive maintenance treatments per cycle
strategy,” the most appropriate timing was at one-third of the rehabilitation cycle; and for
a high cost level strategy or three-time preventive maintenance treatments per cycle
strategy,” the most appropriate timing was at one-fourth of the rehabilitation cycle.
In addition to these documented research studies, individual states continue to monitor the
performance of preventive maintenance treatments, typically by storing the condition
information in their current pavement management systems. As individual states continue to
collect preventive maintenance treatment performance data, and construct test sections to
specifically look at treatment performance and timing relationships, more treatment timing-
related questions will be able to be answered. For those agencies interested in designing and
constructing their own preventive maintenance-related test sections, a draft experimental plan for
such studies is included as an appendix to the final report of NCHRP Report 523 (26).
Innovative Materials and Construction Techniques
There is little active research on this topic. One exception is the information collected as part
of a recent international scanning tour on pavement preservation. In 2001, FHWA and the
American Association of State Highway and Transportation Officials (AASHTO) co-sponsored
an International Scanning Program for Pavement Preservation, which included visits to France,
South Africa, and Australia on a fact-finding mission. The objective of this scanning tour was to
review and document innovative pavement preservation techniques, materials, procedures, and
equipment utilized in host countries, and to evaluate these elements for potential application in
the United States (27). Key findings of the scanning tour include the following:
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Management Perspective and Policies. All three of the countries visited have made a
commitment to design and build long lasting structural pavement sections. Therefore,
these nations focus maintenance activities on surface courses in order to protect the large
investment of the underlying layers. Low cost seals and thin overlays are, therefore, the
primary maintenance techniques instead of more costly types of rehabilitation.
Treatments, Techniques, and Performance. All three countries use only quality materials
for both bitumen and aggregate. Generally, crushed granite and proven polymer-
modified asphalt binders are used. This is ensured through the use of very rigorous
specifications. The primary preservation treatment on high volume roadways in France is
mill and inlay, while South Africa makes extensive use of chip seals (even routinely used
on routes with 50,000 ADT or higher).
Recommendations from the scanning tour include the following:
Construct demonstration projects with deep subbase and deep base designs should be
initiated in different regions of the United States to determine the effectiveness of this
design strategy. Australia and South Africa use these and consider them as long-life
pavement designs.
Include pre-coating of chips in chip seal specifications. This practice is used throughout
Australia and prevents or reduces the loss of chip seal aggregates.
Test and evaluate geotextile-reinforced chip seals in both freeze and no-freeze
environments. This treatment is reported to reduce reflection cracking in Australia and in
Victoria is reported to last 12 to 15 years.
Encourage agencies that do not use modified binders for chip seals to do so. These are
used by Australia for better performing chip seals.
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Encourage agencies to review their specifications and upgrade them where appropriate so
that superior aggregates are used and improved service life is achieved. The scan team
attributes the success of chip seals in all three countries visited to the use of high quality
aggregates and designed chip seal systems.
Encourage agencies to review their design practices for chip seals and consider placing
them on base or subbase courses to prevent moisture infiltration. The Australians follow
this practice.
Thin surface treatments should be applied earlier in the distress cycle. All of the
countries visited try to identify cracking in the 1- to 3-mm (0.04- to 0.12-in) wide range
so that chip seals can be applied at that time.
The successful practice in New South Wales of placing thin (40 to 60 mm [1.6 to 2.4 in])
asphalt overlays on PCC should be investigated.
An innovative construction technique that has gained some exposure in recent years is the
placement of chip seals over fabric to provide a new wearing surface and to help control
reflective surface cracking. The County of San Diego has the best documented experience using
this technique in desert areas with harsh climatic conditions. In some of the desert areas of the
County, the adverse climate and rainfall conditions led to the generation of many large surface
cracks in the asphalt roadways (29). Crack sealing was a common maintenance method for these
desert roads, but the cost of addressing the large quantities of surface cracks did not leave
sufficient funds to apply the final surface treatments to the road. Therefore, in 1987, the San
Diego County Department of Public Works (DPW) developed test sections to evaluate the
performance of several surface treatments including (29):
Chip seal with latex emulsion.
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Slow-curing, 50-mm (2-in) road mix.
Chip seal with ground rubber and paving asphalt binder.
Chip seal with latex emulsion over pavement reinforcing fabric.
Chip seal with latex emulsion on recycled asphalt surface.
All of the treatments were found to seal the road surface well, but only the chip seal over
fabric eliminated the reflective surface cracks. The chip seal over fabric section from the
original 1987 test section was still functioning well (with no need for any additional crack
sealing or filling) in 2003. Due to this success, chip sealing over fabric has become the standard
surface treatment for heavily cracked roads in the desert area of San Diego County. Detailed
material specifications and application procedures are provided in the report (29).
Materials Selection and Mix Design
Although standardized mixture design procedures are readily available for commonly used
rehabilitation treatments such as HMA overlays, mixture design techniques for many preventive
maintenance techniques are still more art than science (4). For example, for treatments such as
fog seals and sand seals, one of the principal design factors is the condition of the existing
pavement. Because surface condition is a fairly subjective input, there is no universal design
procedure. Similarly, mix design procedures for full and partial depth repairs in rigid pavements
vary widely across the US, with varying degrees of performance. Mixture design procedures for
many of the preventive maintenance treatments still need to be developed if wider acceptance of
these techniques is to be realized.
As the majority of flexible pavement preventive maintenance treatments are thin and must
bond to the existing pavement surface, the selection of high quality and compatible materials
(aggregates, binder, and other material components) is necessary to achieve anticipated
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performance. In recent years, the use of polymers to modify emulsions, asphalt cements, and
PCC mixes has generally been found to provide longer pavement lives, but at a higher initial
cost; however, the cost effectiveness of these modified binders and chemical admixtures still
needs to be quantified. Procedures to evaluate thin treatments of various types must be
developed using sound engineering principles.
There are a number of recent specific materials-related research studies that were found as
part of the literature search. Each of these is briefly described below in table 2.
Treatment Performance
The largest number of pavement preservation research-related documents is on the topic of
treatment performance. Much of the recent treatment-related research has focused on analyzing
previously collected performance data (e.g., that stored in a pavement management system) or
the construction and monitoring of test sections carefully designed to display the differences with
different treatment types, construction techniques, materials, or treatment timings. The literature
search and survey specifically focused on identifying the recently completed, ongoing, or
planned treatment-performance research studies. To facilitate the summary and presentation of
treatment-related research that has been completed, is ongoing, or is planned for the future, the
research is divided into those that are associated with treatments applied to bituminous-surfaced
pavements (flexible and composite pavements), and those used on concrete-surfaced pavements.
Over the past decade, a number of research activities have been completed that have focused
on determining the effectiveness of preventive maintenance treatments. A wide variety of
different types of national and state-sponsored studies have been conducted to not only
determine treatment performance, but also to determine the influence of a treatment application
Research Project Title Project Duration Research Sponsor and
Performing Organization Abstract Slurry/Micro-Surface Mix Design Procedure
Start year: 2003 Projected end year: 2007
Sponsor: FHWA (pooled fund study) Managing Organization: California Department of Transportation (Caltrans) Performing Organization: Fugro MACTEC Applied Pavement Technology, Inc.
Caltrans is currently managing an FHWA multistate pool-funded research project on the design and application of slurry seal and microsurfacing treatments, as well as a study of crack sealant materials and application specifications. Participating states include California, Delaware, Georgia, Illinois, Kansas, Maine, Michigan, Minnesota, Missouri, North Dakota, New Hampshire, New York, Texas, Vermont, and industry partners include International Slurry Surfacing Association (ISSA) and Asphalt Emulsion Manufacturers Association (AEMA). This project is evaluating existing and new test methods, evaluating successful constructability indicators, and conducting ruggedness tests on recommended equipment and procedures. Products of this research will include guidelines and specifications and a training program. As part of the project, the research team will also provide oversight on two pilot projects intended to validate the recommended design procedures and guidelines.
Optimizing Gradations for Surface Treatments
Start year: 2003 Projected end year: 2005
Sponsor: North Carolina Department of Transportation and FHWA Performing Organization: North Carolina State University, Raleigh
The primary objective of this research project is to evaluate the current mixture characteristics of surface treatments used in North Carolina and recommend modifications to the current specifications, particularly those related to aggregate gradations, if needed. In addition, the effects of different mixture characteristics on performance will be identified and incorporated in mix design guidelines.
Investigation of Patching Materials for Portland Cement Concrete (PCC) Pavements in the State of Oklahoma
Start year: 2003 Projected end year: 2004
Sponsor: Oklahoma Department of Transportation Performing Organization: University of Oklahoma, Norman, OK
This project is focusing on identifying materials and procedures that can be reliably employed to patch and repair PCC roadways and bridges. The project will also evaluate and define the material properties of the most promising materials and make recommendations as to their use. At least eight commonly used patch materials will be tested for: compressive strength, bond strength, elasticity, and permeability.
Table 2. Examples of recent and ongoing materials selection and mix design-related research.
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47
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on overall pavement performance as well. Some examples of the different types of national and
state-sponsored studies that have been conducted include the following:
Analyses of the preventive maintenance-related data included in the Long-Term
Pavement Performance (LTPP) database (i.e., SPS-3 data for flexible pavements and
SPS-4 data for rigid pavements).
Analyses of agency-collected preventive maintenance data (often retrieved from an in-
place pavement management system).
Construction and monitoring of treatment test sections (these range from a simple field
trial of a particular treatment (i.e., one treatment applied on one project), to more
complex experiments that use a carefully designed experimental plan to investigate
different material and construction factors that may influence treatment and pavement
performance).
Preventive Maintenance Treatments for Bituminous-Surfaced Pavements
Investigations of LTPP SPS-3 Data. Several studies have considered the effectiveness of
four preventive maintenance treatments by analyzing available data in the LTPP database.
Specifically, these studies have analyzed the SPS-3 (flexible pavement maintenance) data which
includes data associated with thin HMA overlays, slurry seals, crack seals, and chip seals. The
following describe some of the details and notable conclusions of the published results
associated with each of these studies.
“Maintaining Flexible Pavements—The Long-Term Pavement Performance
Experiment SPS-3 5-Year Data Analysis” (30)—In a 1998 study, the following
observations were made after 5 years of service.
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- Crack Sealing: The sections receiving crack sealing were smoother than the control
sections. However, the authors did recognize that it was difficult to assess the long-
term IRI trends associated with crack sealing, as new cracks in the pavement
sections did not get sealed, and some sections designated as crack seal treatment
sections did not contain any cracks.
- Chip Seals: Chip seals performed well across all environmental zones and these
applications benefited the performance of pavements in poor condition. The authors
also note that a successful application and performance is dependent on the quality
of the aggregate, the proper handling of the emulsified asphalts, and good
construction control.
- Slurry Seals: Slurry seals performed best in no-freeze climates and on sections with
little cracking. Slurry seals were also found to improve pavement performance
relative to the control sections. Moisture sensitivity was observed on certain
sections.
- Thin HMA Overlays: the authors report that thin HMA overlays performed well,
improved ride quality, reduced rutting, and reduced the severity of reflective
cracking.
“Effectiveness of Maintenance Treatments of Flexible Pavements” (31)—This paper
describes the results of an analysis of SPS-3 data collected in the Southern region. In this
study, a survival analysis was conducted to determine the life expectancy of each
treatment and determine the effect of the original pavement condition on the section
performance. To assess the performance of each treatment, a median survival time was
computed as the number of years until 50 percent of the treatment sections fail. For crack
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sealing applied on pavements in good, fair, and poor condition, the median survival times
were computed as 6.5, 7.2, and 0.75 years, respectively. For chip seals, the median
survival time could not be estimated since the 50 percent failure rate had not yet been
reached after 8 years. For slurry seals applied on pavements in good, fair, and poor
condition, the median survival times were computed as 6.5, 5.0, and 2.5 years,
respectively. For thin HMA overlays applied on pavements in good, fair, and poor
condition, the median survival times were computed as 7.5, 7.3, and 2.2 years,
respectively.
“LTPP Data Analysis: Effectiveness of Maintenance and Rehabilitation Options”
(32)—In 2002, an NCHRP project was completed that analyzed all of the available SPS-3
data to date to again assess the effectiveness of crack sealing, slurry seals, chip seals, and
thin HMA overlay treatments (32). Specifically, the influence of these treatments on IRI,
rutting, and fatigue cracking was investigated and some general observations were
reported. The results from this analysis concluded that crack sealing on these sections
did not demonstrate any beneficial initial or long-term effect with respect to IRI, rutting,
or (fatigue) cracking.
There was some evidence that on rougher pavements the chip seals had an effect on long-
term roughness. Slurry seals did not have any significant effect on long-term roughness.
The data also showed that sections receiving both chip seals and slurry seals exhibited
considerably less cracking than the control sections.
The thin HMA overlay treatment was found to have a small, but significant, effect in the
initial reduction of roughness, and was the only one of the four treatments to have a
significant positive effect on long-term roughness. Similarly, the thin HMA overlay also
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had a significant initial effect on rutting, and had the greatest effect on long-term rutting.
For fatigue cracking, the thin HMA overlay sections were found to have considerably less
cracking than the included control sections. Overall, the authors of this report conclude
that the most effective of the investigated treatments was the thin overlay, followed by
chip seals and then slurry seals.
“Effectiveness of Preventive Maintenance Treatments Using Fourteen SPS-3 Sites in
Texas” (33)—In 2003, a paper was published that describes the analysis of maintenance
data collected from 14 SPS-3 sites in Texas. This study investigated the effectiveness of
the four different preventive maintenance treatments included in the SPS-3 study by
assessing their impact on pavement performance. Specifically, performance was
measured in terms of the Texas Department of Transportation’s distress rating system, in
which a distress score is computed as a function of measurements of shallow rutting,
deep rutting, patching, failures, block cracking, alligator cracking, longitudinal cracking,
transverse cracking, raveling, and flushing.
The authors of this paper concluded that when initial cost was considered, crack sealing
was the best of the four preventive maintenance alternatives for low traffic routes with a
sound underlying pavement structure. Chip seals performed well on a wide range of
pavement conditions, and for most sites, was the rated as the “best performer.” The paper
also stated that based on TxDOT’s experience, the life expectancy of a chip seal is
approximately 7 years. No significant conclusions were drawn about slurry seals in the
study. Finally, the thin overlay treatment was found to be the most effective treatment
for resisting rutting; however, it was also the most expensive of the analyzed treatments.
Therefore, the authors recommended that thin overlays “are best used on high traffic
routes where rutting is a major concern.”
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“Looking at Long-Term Results: Performance of Test Section After 13 Years”
(34)—A 2003 article by Hildebrand and Dmytrow assessed the performance of 11 SPS-3
segments in California after 13 years of service. All of the maintenance strategies were
found to be performing well, with the exception of the rout-and-crack-seal section. After
13 years, the segment receiving crack sealing was only in marginally better condition
than the control section, and the ride quality on the two segments was nearly the same.
Based on these observations, the authors stated that “to obtain long-term service from the
rout-and-crack-seal or control sections, extensive and costly rehabilitation strategies may
be necessary.”
The five chip seal segments analyzed in the study were found to be performing well, with
little raveling, bleeding, or flushing. The slurry seal segment was found to be performing
well, with no delaminating or raveling. Reflective cracking was present on both the chip
seal and slurry seal segments; however, on the slurry seal section, the cracks were sealed
to prevent moisture intrusion and base damage.
The four thin HMA overlays were also performing well, although reflective cracking was
visible on the two conventional overlay sections. The two segments with fiber and
asphalt rubber HMA overlays showed an increased resistance to reflective cracking.
Recent Research for Treatments on Bituminous-Surfaced Pavements. In addition to the
different projects that focused on analyzing LTPP SPS-3 data, the majority of the national- and
state-funded research studies located in the literature have focused on evaluating the
effectiveness of bituminous-surfaced treatments such as crack sealing and thin maintenance
surfacings, such as seal coats (fog seals, chip seals, scrub seals, and so on), slurry seals,
microsurfacings, rejuvenators, and thin and ultra-thin HMA overlays.
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The following summarizes recent treatment-related research (i.e., mostly within the last 10
years). Next, a summary of the ongoing or planned treatment-related research is provided to
better define the current snapshot of research associated with preventive maintenance treatments
typically applied on bituminous-surfaced pavements. This is not intended as an exhaustive
summary of research, but rather as an overview of notable, recent research reports and research-
related articles.
SHRP H-106 and FHWA Long-Term Monitoring Crack Sealing Studies—One of the
most extensive national long-term research studies on this subject began in 1990 when
the Strategic Highway Research Program (SHRP) initiated the “H-106” maintenance
experiment to determine the most effective and economical materials and methods for
conducting crack sealing and crack filling operations (35). Under this study, a total of 31
different treatments (combinations of material, material placement configuration, and
crack preparation procedures) were constructed at 5 different test sites in the United
States (representing 4 distinct climatic zones). The performance of these test sections
was monitored both under the H-106 study and the follow-up FHWA Long-Term
Monitoring (LTM) of Pavement Maintenance Materials Test Sites project. A total of
approximately 7 years of field monitoring data were collected and the results of a
comprehensive statistical analysis of the collected material performance and laboratory
testing data were published along with many material- and configuration-related
recommendations (35). Differences in crack treatment performance were noted among
the surveyed sites, with these differences being attributed to factors such as climate,
traffic, pavement type, crack type, and crack spacing (32). Another by-product of this
research is a Manual of Practice that provides guidance for pavement maintenance
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personnel in the selection, installation, and evaluation of materials and procedures used to
treat (seal or fill) cracks in HMA-surfaced pavements (36).
“Crack Sealing in Flexible Pavements: A Life-Cycle Cost Analysis” (37)—A 1996
paper described Ontario’s experience with crack sealing on flexible pavements. In the
1970s, inappropriate materials and installation procedures were to blame for poor
performing crack seals trials. To correct this, during the 1970s and 1980s, the Ministry of
Transportation of Ontario (MTO) conducted several field trials with the goal of
developing an effective crack sealing procedure, and to study the influence of crack
sealing on pavement performance (37). During the 1980s, guidelines were developed to
provide a basis for the selection of suitable pavements and cracks, sealant materials, and
application procedures. The authors state that “the results of the studies indicate that
sealing cracks is a viable and cost-effective preventive maintenance treatment that can
extend the service life of asphalt pavements by at least 2 years.”
“Cost-Effectiveness of Joint and Crack Sealing: Synthesis of Practice” (38)—This
synthesis nicely documents the joint and crack sealing-related research that has been
conducted since the late 1980s. The results of a comprehensive literature search are
presented with the discussion separated into those research studies that are “supportive”
of the practice of sealing cracks and joints, and those that are “nonsupportive” of sealing
activities. The results of an 11-question survey of SHAs on their current sealing practices
are also presented. The authors conclude that there are some “controversial and
ambiguous research results in the literature regarding the cost-effectiveness of joint/crack
sealing of flexible and rigid pavements.” Therefore, it would be inappropriate for any
agency to adopt a no-seal policy without sound research to justify the current sealing
practices.
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“Bituminous Crack Filling Test Section on US-10 Near Evart” (39)—The stated
purpose of this study was to have a side by side comparison of many different filler
materials used to fill cracks in bituminous pavements in Michigan. To achieve this
objective, 21 test sections including 9 different material types were constructed in 1995.
These test sites were visually rated at 1, 3, 7, 11, 15, and 24 months after construction.
Specifically, the inspections documented failures and distresses consisting of bridging,
abrasion, adhesion/cohesion loss, bleeding, and tracking. This report documents the
design of the experiment, test site construction details, the monitoring process, and
conclusions and recommendations.
“Field Review of Preventive Maintenance Treatments in Michigan” (40)—In 1999,
2000, and 2001, Michigan conducted a field review of its preventive maintenance
treatments. Some of the findings associated with the more common treatments are
described below:
- Crack Sealing: The analysis of the bituminous crack sealing sections found that
newer bituminous surfaces that received crack sealing generally performed better
than older bituminous layers. A total of 50 overband crack filling projects were also
reviewed in this study. Based on the observed distress in these sections, the author
states that the data indicated that “the overband crack fill treatment has a small, if
any, affect on extending the life of the pavement structure”. Because of the observed
poor performance of this treatment, the author recommends that MDOT review their
“project selection guidelines for projects on a composite pavement structure”. In
response to these results, MDOT chose to use a “more elastic type crack filler” on
future overband crack filling projects.
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- Chip Seals: This study concludes that presealing cracks before the placement of a
chip seal is imperative for its success. This was important, as it was concluded that
“a single chip seal alone will not eliminate the intrusion of water through large
cracks into the underlying pavement structure for a long period of time.” The
MDOT’s Capital Preventive Maintenance (CPM) guidelines state the following
estimated extended service lives:
- Single chip seal on a flexible pavement: 3 to 6 years.
- Double chip seal on a flexible pavement: 4 to 7 years.
- Double chip seal on a composite pavement structure: 3 to 6 years.
- Microsurfacing: The estimated extended service lives associated with
microsurfacing are the following:
– Single course microsurfacing on a flexible pavement: 3 to 5 years.
– Multiple course microsurfacing on a flexible pavement: 4 to 6 years.
The practice of presealing cracks before placing a two-course microsurfacing
treatment did not notably increase the service life over a section without crack
sealing.
- Nonstructural Bituminous Overlay and Surface Milling with a Nonstructural
Bituminous Overlay: MDOT’s CPM guidelines estimate that both of these treatments
should extend the service life of a flexible pavement from 5 to 10 years, and extend
the life of a composite pavement 4 to 9 years (40). All but one of 23 reviewed
projects equaled or exceeded these expected life extending values.
“Field Evaluation of Pavement Surface Treatments In Wyoming” (41)—This study
monitored the performance of 23 test sections over 5 years, with efforts made to
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eliminate the effects of environmental and traffic variations on surface treatment
performance (41). The authors conclude that choosing the optimum combination of
aggregate and asphalt binder is essential for achieving good treatment performance.
Also, it was observed that cracking is affected by choice of binder, while surface friction
resistance is affected by aggregate type alone.
“SHRP Chip Seal” (42)—A 2001 report sponsored by the Colorado Department of
Transportation discusses the evaluation of three chip seal test sections and one control
section in Colorado. The three test sections consisted of a standard chip seal, a standard
chip seal with a fog seal, and a lightweight chip seal. Originally placed in 1997, these
test sections were monitored at 6 months, 1 year, and 2 years after construction under a
previous research study conducted by Arizona State University. The sites were evaluated
visually and through the use of skid testing, FWD, and profilograph equipment. Some
notable conclusions in this report include the following:
- Both the lightweight and standard chip seals postponed environmental cracking
and, therefore extended the life of the pavement.
- Very little chip loss was observed in any of the three test sections and, overall, the
treated sections were in better condition than the untreated section.
- No apparent long term advantage to applying a fog seal over a standard chip seal
was observed.
“Effectiveness of Highway Pavement Seal Coating Treatments” (43)—This paper
presents the results of a research study conducted in Indiana in which the effectiveness of
seal coating treatments (chip and sand seals) was assessed by analyzing historical Indiana
DOT data. As part of this study, the authors reviewed the past literature on this subject,
and noted past studies that both investigated observational (historical) data and data
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obtained from controlled experiments. Past studies that had investigated observational
data included those by Young, Robinson, and Rowley (44), Rajagopal and George (45),
Mouaket, Sinha, and White (46), and Al-Mansour and Sinha (47). Past studies that
investigated data obtained from a controlled experiment included those conducted by
Smith, Freeman, and Pendleton (48) and Syed, Freeman, and Smith (49).
The actual research study developed models for initial performance jump and rate of
deterioration (both in units of present serviceability index [PSI]) based on the historical
data analyzed for 35 pavement sections in Indiana. While the authors admit that a
performance condition rating (PCR) may be a more appropriate performance measure
than PSI, due to a lack of PCR data, PSI data were used. The authors state that the results
of this study support the inherent belief that pavements in relatively poor condition were
associated with higher initial performance jumps but lower reductions in their rates of
deterioration (43). This implies that there are greater benefits (effectiveness) of seal
coating on relatively good pavements compared to relatively poor pavement when
considered over an extended period of time, but lesser benefits when considered the very
instant the treatment is applied. Another product of this involved the determination of the
most cost-effective maintenance strategies for different pavement families in the state of
Indiana. These optimal maintenance strategies were determined by conducting a cost-
effectiveness study of data supplied by the Indiana Department of Transportation.
“High Volume/High Speed Asphalt Roadway Preventative Maintenance Surface
Treatments” (50)—Although South Dakota has found chip seals and sand seals to
mostly be reliable treatments, there have been some notable failures, especially on high-
volume, high-speed roadways. Therefore, the objectives of this project were to
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investigate the use of chip seals for such applications and to make recommendations to
improve their performance. This project also involved the development of guidelines for
the design and construction of chip seals.
As part of this project, test sections were constructed for 12 different chip seal designs
that included two aggregate types (quartzite and natural aggregate) and alternate chip seal
designs with new gradations and other modifications and enhancements. Based on these
efforts, recommendations are provided to improve chip seal performance.
Investigation of Thin Maintenance Surfaces: Phases I and II (TR-435) (Center for
Transportation Research and Education [CTRE])—An ongoing study in Iowa is
developing qualitative and quantitative guidelines for using thin maintenance surfaces
(chip seals, slurry seals, and microsurfacing) on asphaltic concrete and bituminous roads
(5,51). This project, which began in 1997, has two phases: phase one (which ended in
April 1999) included the following:
- Conduct a survey of local transportation officials to determine current Iowa
practices.
- Construct and monitor test sections at three different locations (two constructed in
1997 and one in 1998).
- Develop qualitative guidelines to provide guidance on which roads are good
candidates for thin maintenance surfaces, when these treatments should be placed,
and what type of treatment should be selected (5).
In Phase II of the Iowa DOT research study, TMS quantitative guidelines were developed
to limit the variation in application between users (6). Allowable distress quantities were
selected by considering an appropriate surface condition index (SCI) for given
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treatments, traffic levels, and distresses. The new guidelines, based on the PCI rating
system, were developed using condition data collected from four test sections (three from
Phase I and one additional test site constructed under Phase II) placed over 3 years
“Impact of Sealers/Rejuvenators on Short-Term Modulus of Asphalt Concrete
Layers (Draft Report)” (52)—In 2001, the Portable Seismic Pavement Analyzer
(PSPA) was used at three test sites to monitor the change in the modulus of several
asphalt concrete pavement sections shortly after they were treated with sealers or
rejuvenators (52). The three test sites are located near Winslow, Arizona; near Salton
Sea, California; and near Sacramento, California. A number of different sealers and
rejuvenators were tested at each of the three test sites. An analysis of the results found
that although the measurements from the PSPA device were reasonably repeatable, it was
found that the change in modulus between depths of 2.5 cm (1 in) (upper resolution of the
device) to 10 cm (4 in) is either small or insignificant. The author of this draft report
recommended that follow up testing be completed on these same sites to try and
determine the long-term effect of these treatments.
“Modified Chip Seal Surface Treatments vs. Conventional Chip Seal Surface
Treatments” (North Dakota DOT)—A 2002 North Dakota state report describes a
study conducted by the North Dakota DOT that evaluated modified types of chip seal
surface treatments and compared these modifications to the conventional chip seal
surface treatments currently used on North Dakota roadways (53). Two separate projects
were constructed in 1996 and monitored for 5 years. The first project consisted of 10
unique combinations of 2 different asphalt materials, and 5 different application methods.
The second project looked at the use of a fog seal on a traditional chip seal design. The
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lessons learned from the study and recommendations made were documented in the
report.
“Construction and Performance of an Ultrathin Bonded Hot-Mix Asphalt Wearing
Course” (54)—The two primary objectives of this research were to 1) document the
materials and construction procedures associated with ultrathin bonded overlays, and 2)
to evaluate the treatment performance. This paper includes brief summaries of published
reports that describe ultrathin overlay projects constructed in 1992 and 1993 in
Pennsylvania, Texas, and Alabama. Visual inspections were also conducted on numerous
recently constructed ultrathin overlay projects in Alabama, Missouri, Minnesota, Iowa,
and Colorado. The authors report that ultrathin overlays provide excellent aggregate
retention, have an excellent bond to the existing surface (i.e., delamination is usually not
a problem), and have excellent macrotexture qualities.
NovaChip® Field Trials in Washington State (55)—In this report the authors document
the construction of an ultra-thin overlay field trial project in Washington. This trial
project was constructed to evaluate Novachip’s constructability, performance, and cost
effectiveness for use on low volume roads in Washington. Observations from the trial
found that the ultra-thin overlay could be placed quickly on roads with many road
approaches and cross streets, and traffic could cross the new mat 10 minutes after
placement. In addition, although reflective cracks were present after 22 months of
monitoring, the cracks were still tight. One concern that Washington state personnel did
have about the use of ultra-thin overlays, is whether they are resistant to wear from
studded tires.
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Research In Progress Associated With Treatments on Bituminous-Surfaced Pavements.
This section summarizes ongoing research studies relevant to studies of treatments applicable on
bituminous-surfaced pavements. Project titles and brief synopses of the published reports
located in the literature review are provided below.
“Development of Performance Guidelines for Selection of Hot-Pour Crack
Sealants” (National Research Council of Canada, Virginia Tech, and the Virginia
Transportation Research Council)—The National Research Council of Canada,
Virginia Tech, and the Virginia Transportation Research Council are working together in
an ongoing study to achieve a means of selecting durable crack sealant materials for use
on pavements. The focus of the project is to establish performance guidelines that will
ensure that sealants with superior performance and greater durability are selected for
crack sealing. The project is structured to provide: (1) a short-term aging procedure that
simulates sealant aging during installation; (2) long-term aging procedure that simulates
weathering during service; (3) a method to assess the low temperature performance of
sealants; and (4) a sealant adhesion test. The project is scheduled to be completed in
2006.
“Crack Sealing Cost Effectiveness” (Montana DOT)—Ongoing research is focused on
determining the most economical and effective materials and methods for sealing cracks
in flexible pavements in Montana. Test sites were constructed at four different locations
in the state to collectively investigate 11 sealant materials and 6 crack sealing techniques.
The test locations were monitored for five years (ending in 2002) following the
guidelines of the SHRP H-106 project. Sealant failures observed during field monitoring
are categorized according to material failures (primarily adhesion and cohesion failures),
and construction failures (primarily secondary cracking) according to Strategic Highway
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Research Project (SHRP) criteria. This work is being conducted by Montana State
University for the Montana Department of Transportation and is expected to be
completed in 2004.
“Effectiveness of Crack Sealing on Pavement Serviceability and Life” (Ohio
DOT)—An ongoing study is investigating the cost-effectiveness of Ohio’s current crack
sealing practices on serviceability and life (56). In this study, the effectiveness of crack
sealing of flexible and composite pavements is being determined through a series of well-
controlled field evaluations conducted over a period of nearly 10 years. Since the
project’s inception in the year 2000, the research team has designed an experimental plan
for the project, set up test sections, conducted preliminary pavement condition
evaluations, and established guidelines for further monitoring. By collecting and
analyzing field performance data, this study is expected to help answer the following
three questions:
- Do ODOT’s existing crack sealing practices enhance pavement performance?
- Are crack sealing practices cost beneficial?
- What is the optimum timing for crack sealing?
ODOT will continue to collect data on these sections through the year 2010.
“Comparison of Hot Poured Crack Sealant to Emulsified Asphalt Crack Sealant”
(Texas DOT)—In Texas, hot rubber asphalt has been the most commonly used material
for filling and sealing cracks. However, safety has been an issue with the use of hot
rubber asphalt crack sealants, and vehicle tires can easily pick up material if sufficient
adherence is not developed between the sealant and the crack sides. Because of potential
safety problems, some Texas Department of Transportation (TxDOT) districts had started
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using cold pour asphalt emulsion crack sealants. While the cold pour material has the
tendency to penetrate into the crack more effectively and easily than the hot pour rubber
asphalt, the cold pour sealant requires longer setting and curing time (especially in areas
of high humidity). Because the performance and costs associated with cold pour sealants
are not well documented, TxDOT initiated a research project in 2000 to address these
issues. The specific objective of this study is to compare the cost effectiveness; the ease
and safety of installation, the performance, and the life cycle cost for hot rubber asphalt
crack sealant cold pour asphalt emulsion crack sealant, and cold pour asphalt emulsion
joint sealant. This work is currently being conducted by the Center for Transportation
Research (University of Texas).
Analysis of Idaho LTPP GPS and SPS Data to Predict Pavement Performance
(Idaho DOT)—Similar to previous research studies that investigated LTPP SPS data, the
objective of this ongoing study is to analyze the Idaho LTPP data to 1) study the
effectiveness of preventive maintenance techniques in Idaho; 2) develop performance
prediction models that will address pavement structure, material properties, effects of
environment and traffic loading; and 3) develop recommendations that address pavement
performance issues in Idaho and optimum methods of preventive maintenance treatments.
Preventive maintenance treatments included in the SPS-3 study include crack sealing,
chip seals, slurry seals, and thin HMA overlays. This project is sponsored by the Idaho
Department of Transportation and the work is being conducted by the University of
Idaho.
“Field Evaluation of Crack Seal Methods, Sealant Types and Effectiveness”
(National Center for Pavement Preservation [NCPP])—The National Center for
Pavement Preservation (NCPP) is currently working with the National Transportation
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Product Evaluation Program (NTPEP) sealant committee to establish test decks in each of
the AASHTO environmental zones to study asphalt crack sealing and concrete joint
sealing performance. The objective of such a study is to report the performance of
materials, application techniques, and specifications for crack seal products in field
experiments in several states. Some standards would be incorporated from research
findings being developed from the study mentioned above (Development of Performance
Guidelines for Selection of Hot-Pour Crack Sealants) being conducted by the National
Research Council of Canada, Virginia Tech, and the Virginia Transportation Research
Council. Under this planned project, NCPP would monitor and track the material
performance. This proposed project is not yet funded.
Evaluation of Different Crack Sealants on Asphalt Pavement (North Dakota
DOT)—A 2001 state report (ND 96-04) describes a study conducted by the North
Dakota DOT that evaluated the effective sealant capabilities of four different sealant
types from one sealant manufacturer, at one project location in the state. This project,
constructed in 1996, was monitored twice a year (winter and summer evaluations)
through 2000. The lessons learned from the study and recommendations made were
documented in the report (57).
“Maintenance Cost Effectiveness Study” (Arizona DOT)—In 1997, a three-phase
long-term study on the cost effectiveness of maintenance treatments was begun. The
original scope of this project states that the project objectives were to (1) Identify the
maintenance surface treatment alternatives suitable for evaluation by ADOT; (2) Develop
a consensus on which alternatives to test; (3) Determine the performance and cost
effectiveness of these treatments; and (4) Identify procurement issues which inhibit
effective pavement maintenance and recommend solutions to these issues.
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Phase I of the project consisted of a wearing course experiment, while phase II
concentrated on surface treatments. In the early stages of this project, 193 test sections
were constructed to evaluate treatment performance. Phases I and II were completed in
2002 with the construction of an additional 84 test sections. Phase III is a
sealer/rejuvenator experiment that is now being conducted in conjunction with the
FHWA National Sealer Binder project (see the following project update). As part of
Phase III of this project, an additional 60 to 70 sealer/rejuvenator test sections are to be
placed in addition to the 193 constructed for phases I and II of this project.
“Life of Preservation Seals” (Utah DOT)—The effectiveness of pavement preservation
seals is a critical aspect of UDOT’s pavement management program. In 2002, a study
was sponsored by the Utah Department of Transportation that is focusing on estimating
the life of seal coats for programming purposes, and recommending improvements in the
Department’s policies, procedures, and design methods for seal coats. Open graded
surface courses and chip seals are the main focus of the project. This work is being
conducted by the University of Utah.
“The Use of Microsurfacing for Pavement Preservation” (Maine DOT)—The
objective of this Maine DOT experimental construction project is to evaluate the
performance of two microsurfacing projects. Test and control sections are currently
being compared using frictional resistance, reflective cracking, rutting and roughness.
This work is supposed to end in the year 2006.
“Analyze Existing Fog Seal Asphalts and Additives” (Texas DOT)—This ongoing
project is meant to determine the impact of fog seals and rejuvenators on permeability,
strength, binder viscosity, and depth of penetration. Pavements sealed within the last few
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years and new treatments will be tested in both years of the 2-year study. As part of this
research, guidelines will be produced that address the best practices, selecting appropriate
candidates, pre-treatment work, application rate and treatment type, application
suggestions, curing time, and performance. This study, which is expected to be
completed in 2006, is being sponsored by the Texas Department of Transportation and is
being conducted by the Texas Transportation Institute.
“Evaluation of Preventive Maintenance Treatments” (Mississippi DOT)—In 2005,
the State of Mississippi is scheduled to construct two different preventive maintenance
surface treatment field trials. In this study an evaluation will be performed of two seal
treatments to provide cost/benefit data and assist in the updating of Mississippi DOT’s
“decision trees” that are utilized to determine which preventive maintenance treatment
provides the most benefit for each pavement condition. This project is expected to end in
2008.
“Thin Maintenance Surfaces―Phase III: Municipal Streets and Low-Volume Rural
Roads (TR-507)” (Center for Transportation Research and Education [CTRE])—
This ongoing project is a follow up study to a previous project (TR-435) that developed
qualitative and quantitative guidelines for thin maintenance surfacings (see preceding
project description) (58). The objective of this ongoing project is to fully develop a thin
maintenance surface technology transfer program specifically for municipal and
secondary road personnel. The project will also evaluate the performance of maintenance
treatments that were not tested in Phase I and Phase II by constructing field test sections
and observing their performance. This project is being conducted by the Center for
Transportation Research and Education at Iowa State University under the sponsorship of
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the Iowa Highway Research Board. Work on this project began in 2003 and is expected
to be completed in December of 2005.
“Microsurfacing Performance Evaluation” (North Dakota DOT)—The North Dakota
DOT is currently conducting a research project to evaluate the performance and cost
effectiveness of microsurfacing as a method to fix rutting and depressed transverse
cracks. In 2003, a test section was constructed that contained a microsurfacing treatment
and a traditional overlay. The performance of both of these treatments will be evaluated
annually for 7 years (or until failure). The physical characteristics that will be compared
between the two sections include distresses, overall surface condition, performance, ride,
and skid resistance. The design and construction details for this project are summarized
in a Construction report available from the North Dakota DOT (59).
“Effectiveness of Thin Hot Mix Overlay on Pavement Ride and Condition
Performance” (Ohio DOT)—An ongoing project sponsored by the Ohio Department of
Transportation is focusing on 1) determining the cost effectiveness of using thin hot mix
asphalt overlays as a preventive maintenance technique based on experience in Ohio; 2)
determining under what circumstances a thin hot mix overlay would be suitable; and 3)
determining when to construct the treatment to maximize its benefits. Phase I of this
study began in 2002 with a review of existing literature on thin-overlays and an
assessment of whether sufficient data are available in Ohio to perform the subsequent
analysis. This work is being conducted by the University of Toledo and is expected to be
complete in 2005.
“Durable Wearing Surfaces for HMA” (Colorado DOT)—In 2002, the Colorado
Department of Transportation began a study (No. 10.37) that is looking at the
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effectiveness of different wearing surfaces for their HMA pavements. As part of this
study, a NovaChip® project (ultra-thin HMA overlay) was constructed in 2002 and an
open-graded friction course (OGFC) project was included in this study in 2003. These
projects are being monitored to determine their effectiveness over time. An expected end
date for this project is 2006.
In addition to the ongoing research studies highlighted above in the discussion of recent
research, the 2004 pavement preservation questionnaire found that many states are currently
conducting agency-sponsored research related to one or more surface treatments on flexible
pavements. The following list summarizes additional identified treatment-related research:
Survey responses had little mention of any crack filling- or crack sealing-related agency
sponsored research.
Nevada indicated that they have experience with the use of microsurfacing and slurry
seals. In addition, they indicate that asphalt surface treatment test sections have been
conducted that were evaluating different treatments such as chip seals, foamed asphalt,
cape, CIR, reflex, and so on.
Caltrans reports that they have conducted preventive maintenance warranty (1-year) pilot
projects for: chip seals (conventional and rubberized asphalt concrete [RAC] binder),
slurry seals, microsurfacing, RAC thin-layer high-binder friction courses, RAC overlays
(thin gap-graded and open-graded).
Illinois reports that they will be conducting a series of 27 projects in 2004 and 2005 that
will investigate various pavement preservation techniques including chip seals,
microsurfacing (1-pass and 2-pass), and slurry seals. These projects will be monitored to
determine both pavement condition improvement and treatment performance.
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Massachusetts reports a research interest in profile milling, micro-milling, thin HMA
overlays (< 38 mm [1.5 in]), paver placed surface seals, single course microsurfacing, the
combination of cold milling and thin overlay (< 38 mm [1.5 in]), and ultra-thin overlays
(<19 mm [0.75 in]).
Nebraska reports the placement of a proprietary fog seal product (Bio Span) on “a couple
of projects” and the planned future monitoring of those projects. In addition a scrub seal
project was conducted “a couple of years ago” and continues to be monitored.
A review of Ohio’s 2005, 2006, and 2007 research plans showed two planned pavement
preservation-related research projects. The objective of a proposed 2006 RFP titled
Effectiveness of Crack Sealing on Pavement Serviceability and Life, Phase 2 is to assess
the effectiveness of ODOT’s crack sealing practices by analyzing the data from an
ongoing crack sealing study. A second preservation-related study titled Effectiveness of
Chip Sealing and Microsurfacing on Pavement Serviceability and Life is expected to start
in 2007. This second study has the goal of statistically determining the cost effectiveness
of using chip seals or microsurfacing as preventive maintenance techniques.
Virginia is currently monitoring “macro texture surface treatments (RoadArmor)” and
ultra-thin overlays (NovaChip®).
Washington is currently evaluating NovaChip® and microsurfacing test sections.
Missouri is currently monitoring chip seal projects with different designs.
North Dakota participated in “SHRP test section projects, microsurfacing construction
and maintenance operations,” and crack sealing operations.
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Preventive Maintenance Treatments for Concrete-Surfaced Pavements
This section summarizes recent (i.e., within the past 10 years) and ongoing research studies
on PCC-surfaced pavements identified in the literature search. The project titles and brief
synopses of these different research efforts are provided below.
Joint Resealing. Joint and crack sealing is a commonly performed pavement maintenance
activity that reduced the amount of moisture that can infiltrate a pavement structure and helps to
prevent the intrusion of incompressible materials. In the past decade, several researchers have
investigated the merits and deficiencies of current joint resealing and crack sealing materials,
designs, and practices. These are discussed below.
SHRP H-106 and FHWA Long-Term Monitoring Joint and Crack Sealing
Studies—In 1991, a nationwide study (SHRP Project H-106) investigated joint and crack
sealing materials placed in different joint configurations. As a result of that study, a
manual of practice was published that addresses the effectiveness of various sealing
materials and procedures for pavements under different conditions (60). Following the
conclusion of SHRP H-106 in 1993, the FHWA sponsored the Long-Term Monitoring
(LTM) of Pavement Maintenance Materials Test Sites project to continue monitoring the
performance of these experimental repairs. This monitoring study concluded in 1997 and
resulted in an updated manual of practice (61).
“LTPP Pavement Maintenance Materials: SPS-4 Supplemental Joint Seal
Experiment (62)—The effectiveness of joint sealing and resealing has also been
investigated by analyzing the data collected as part of the LTPP SPS-4 study. In 1991,
1992, and 1995, six additional joint sealing test sites were constructed adjacent to the
SPS-4 sites, and monitored under the FHWA LTM project. Specifically, these 6
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supplemental sites included the installation of 29 unique joint sealant treatments (i.e,
combinations of sealant material and installation method) that were constructed and
monitored under this project. This report summarizes the installation details for the
supplemental test sites, a summary of material testing and field performance associated
with the sites, and the results of a statistical analysis conducted on the collected field
performance data.
“Edge-Joint Sealing as a Preventive Maintenance Practice” (63)—A 2003 paper
discusses a research effort performed at the Minnesota Road Research test facility to
investigate the effectiveness of sealing the longitudinal edge joint on PCC pavements.
The authors reported that the Minnesota Department of Transportation (Mn/DOT) does
not routinely seal the lane shoulder joint on PCC pavements with asphalt shoulders
because of the difficulty in getting an effective seal. This study was conducted to
investigate the water flow reduction when the lane-to-shoulder joint was routed and
sealed. Pavement sections were instrumented to provide automated measurements of
changes in pavement moisture and drainage due to varying climate conditions. Concrete
test sections and longitudinal edge drains were constructed. Data was collected before
and after edge joints were sealed on concrete sections. There was no significant
difference in the volume drained between the control and the test section prior to sealing
the joint on the test section. After sealing the edge joint, there was a significant reduction
in the volume drained from the test section. The results of this study indicated that
sealing the edge joint on concrete pavements with bituminous shoulders can reduce the
total volume of water entering the pavement system by as much as 85 percent for a given
rain event. The authors conclude that sealing the longitudinal edge joint on concrete
pavements should be considered as a pavement preventive maintenance treatment.
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“The Great Unsealing: A Perspective on Portland Cement Concrete Joint Sealing”
(64)—A 1997 paper by Shober discusses Wisconsin’s current practice of not sealing
joints on PCC pavements. The influence of crack/joint sealing on PCC pavement
performance has been studied by the Wisconsin Department of Transportation (WisDOT)
for 50 years. By 1967 there was “substantial documentation that filling and refilling of
contraction joints had no beneficial effect on pavement performance” (64). By 1984, it
was concluded that pavement with unsealed joints had better overall performance than
pavements with sealed joints. Because of this research, in 1990, WisDOT passed a
policy that eliminated the practice of sealing PCC joints. WisDOT has attributed an
annual savings of $6 million to eliminating this practice, with no loss in pavement
performance. While there continues to be resistance by other agencies to adopt the
WisDOT policy of not sealing joints, the research that has been completed in Wisconsin
has caused other states to begin their own studies to determine the cost effectiveness of
joint sealing practices in their states.
“Performance Evaluation of Drained Pavement Structures” (65)—Another study in
Wisconsin is documented in a 1998 report by Rutkowski, Shober, and Schmeidlin.
Although this study focused on determining the effectiveness of different positive
drainage methods used on PCC pavement structures (i.e., open graded structures,
drainage systems, and so on), part of the study focused on determining whether or not
transverse joint sealing was an effective maintenance technique. The results of this study
supported the conclusions of the Shober study presented above (64), which states that
transverse joint sealing did not benefit pavement performance and therefore was not cost
effective (65,38).
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“Joint Seal Practices in the United States—Observation and Consideration” (66)—
In a 1998 paper, Morian and Stoffels assessed current agency joint sealing practices in
the United States. The paper begins with general discussions of the purpose of joint
sealing, factors considered in the joint seal design process, and explanations of common
sealant materials. Next, the practice of not sealing joints (used by a few agencies) is
discussed, followed by some typical costs associated with different sealant types. Based
on the information reviewed while writing this paper, the authors offered the following
conclusions:
- The sealing of pavement joints may not be cost-effective with respect to the
exclusion of water (which leads to the development of subgrade erosion) in
pavement locations with a free draining, coarse-grained subgrade material.
- The performance differences between sealed and unsealed joints may be difficult
to discern in locations where pavement joints are thermally locked a large portion
of the year.
- The incidence of joint spalling due to incompressible material in the joints and
blowups due to pavement migration has not been adequately discussed by those
citing the merits of unsealed joint practices.
- A single 3-mm (0.125-in) saw cut is not adequate to appropriately deal with slab
contraction movement in temperature climates, which experience near -18°C
(0°F) temperatures, and in greater than 38°C (100°F) high temperature extremes.
- Problems experienced by many joint seal designs result from inadequate
construction quality or when temperatures during the early cure cycle of rigid
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pavements do not vary over a sufficiently wide range; thus all joints do not
initially crack the full depth of slab.
“Cost-Effectiveness of Joint and Crack Sealing: Synthesis of Practice” (38)—As
introduced previously under the research associated with treatments for flexible
pavements, this synthesis nicely documents the joint and crack sealing-related research
that has been conducted since the late 1980s. The results of a comprehensive literature
search are presented, with discussion separated into those research studies that are
“supportive” of the practice of sealing cracks and joints, and those that are
“nonsupportive” of sealing activites. This synthesis concluded that there are some
“controversial and ambiguous research results in the literature regarding the cost-
effectiveness of joint/crack sealing of flexible and rigid pavements.” Therefore, the
authors state that it would be inappropriate for any agency to adopt a no-seal policy
without sound research to justify the current sealing practices.
“Cost Effectiveness of Sealing Transverse Contraction Joints in Concrete
Pavement”—To further explore the joint sealing issue, a national research project titled
Cost Effectiveness of Sealing Transverse Contraction Joints in Concrete Pavement,
began in 2003. This project (Task 9 of FHWA’s Concrete Pavement Technology
Program [CPTP] program) is focusing on collecting and analyzing performance data,
FWD data, and profile data from over forty different individual joint sealant experimental
projects in many different states in the US. The overall objective of this project is to
provide conclusions that will assist states in determining if sealing transverse contraction
joints is warranted for their pavement cross-sections and slab dimensions, materials,
climatic, and traffic conditions.
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Dowel Bar Retrofitting. Since the early 1980s, more and more state agencies have
retrofitted existing undoweled JPCP pavements in an effort to improve joint load transfer at
transverse joints, thereby stopping or slowing the progression of joint faulting at those joints. In
general, recently completed research studies on this topic have cited many examples which
indicate that dowel bar retrofitting (typically followed by diamond grinding) is a very effective
preventive maintenance strategy (67,68). For example:
Since 1983, Puerto Rico has installed many kilometers of retrofitted dowel bars as part of
their CPR program. In 1991, a review of over 7,000 installed dowel bars found that less
than 0.5 percent of the repairs have failed (67).
The South Dakota Department of Transportation (SDDOT) has retrofitted nearly all of its
JPCP on the Interstate system and reports less than 0.5 percent failures. SDDOT has
begun to retrofit JPCP sections of the secondary highways (67).
Washington State estimates that the cost for CPR is $40,000 less per km ($64,000 less
per mi) of 2-lane roadway than a conventional 90-mm (3.5-in) asphalt overlay and will
last 10 to 15 years. Their estimate includes slab replacement, dowel bar retrofitting in the
truck lane, diamond grinding, and joint and crack resealing. For the 300 km (190 mi) of
two-lane roadways completed by 1997, this represents a savings of $12 million (67). In
recent years Washington State DOT has modified the design and construction of their
dowel bar retrofit activities based on 10 years of experience with the technique. The
following summarizes general lessons learned over that decade of experience (68):
- Construction inspection is one of the primary factors for ensuring the success of a
dowel bar retrofit project.
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- Using proper slot cutting and material removal techniques are critical to the
success of a DBR project.
- Dowel bar retrofitting is appropriate on PCC pavements with less than 10 percent
slab replacement and average faulting between 3 mm (0.125 in) and 13 mm
(0.5 in).
In addition to the reporting of past research experience with dowel bar retrofitting, the
literature search also turned up a number of ongoing projects that are investigating the cost
effectiveness of this preventive maintenance technique.
Pooled Fund Study to Investigate the Cost-Effectiveness of Dowel-Bar Retrofit
Projects—In 2001, a dowel-bar retrofit research project was constructed in Ukiah,
California as part of a pooled fund project established between California, Minnesota,
Texas, and Washington (69). This study has the following objectives (68):
- Investigate the feasibility of dowel bar retrofit based on the conditions of existing
slabs.
- Evaluate the load transfer restoration provided by dowel bar retrofit.
- Determine the expected life of dowel bar retrofit.
- Determine the mechanism of failure.
- Develop best practice procedures in the areas of design, materials, and
construction.
- Identify appropriate rehabilitation treatments based on life cycle costs.
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The primary benefits of this project are to provide information and tools to design and
construct dowel bar retrofit projects for maximum performance and to determine whether
and under what conditions dowel bar retrofit is the most cost-effective strategy (68).
“Dowel Bar Retrofit: STH 13 Construction and One-Year Performance Report”
(70)—This report focuses on a Wisconsin DOT rehabilitation project on State Highway
13 in Wisconsin. The test section for this project was constructed in 2001 and used
retrofitted dowel bars to restore load transfer and prevent further faulting. Six patch
materials, two dowel bar materials, and sealed vs. unsealed joints are all examined in this
study. The study found that deteriorated joints at the base of the replacement slots posed
significant problems. Areas of thin pavement also pose problems. The lack of
uniformity on the stainless steel dowels make it difficult to fit caps on the end of the
dowels. Cracking of the pavement from the dowel bar slots has been noticed on some of
the pavement sections and additional investigation as to its cause is recommended. The
study makes observations on the performance of all six of the patch materials. Two of
the mortar mixes have experienced debonding problems that can probably be attributed to
drying, plastic, or chemical shrinkage. Good workmanship was critical to the
performance of the dowel bar retrofit test sections. Test sections will continue to be
monitored and inspected for deterioration, spalling, or scaling of the patch material,
deterioration of the pavement around the dowel bar slots, faulting of the slabs, corrosion
of the dowel bars, and overall pavement performance.
“Evaluation of Dowel Bar Retrofits for Local Road Pavements” (Iowa DOT)—The
objectives of this research are to: (1) evaluate the feasibility of using elliptical or round
dowels to retrofit an 8-inch depth local road pavement as part of a retrofit/grind
rehabilitation project; (2) evaluate the impact of applying 2, 3, or 4 dowels in the outer
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wheel path only, in a local pavement on pavement performance; (3) evaluate the impact
of utilizing fiber-reinforced polymer (FRP) or steel dowels in the retrofit of the test
pavement, on long-term performance; and (4) determine the relative cost of elliptical
shaped dowels (FRP and steel) for the retrofit project. This work is being conducted by
Iowa State University for the Iowa Department of Transportation, and is expected to be
complete in 2008.
“Dowel Bar Retrofitting of Cracks In PCC Pavements” (Michigan DOT)—From
1997 through 2000, the Michigan DOT constructed seven dowel bar retrofit jobs to
evaluate the cost effectiveness of this technique. The specific objective of this project is
to see if it is more cost effective to dowel bar retrofit a crack at an early stage rather than
conduct a full-depth repair once it has deteriorated. Current indications are that dowel
bar retrofitting a crack is about one-third the cost of a full-depth repair. The yearly
monitoring of these projects has shown that the majority of the retrofits are performing as
expected (71). MDOT is planning to continue dowel bar retrofits in the future.
Diamond Grinding. Diamond grinding is the removal of a thin layer of hardened PCC
pavement surface using closely spaced, diamond saw blades mounted on a rotating shaft. As
diamond grinding eliminates surface irregularities, it is a very effective method for restoring or
improving ride quality (including the removal of joint faulting), improving surface friction, and
reducing tire/pavement noise in noise sensitive areas (72). As with many of the other preventive
maintenance treatments, the cost effectiveness and expected performance of diamond grinding
has been the focus of a few recent and ongoing research projects.
“The Longevity and Performance of Diamond-Ground Concrete Pavements” (73)—
A recently completed national study investigating the performance of diamond ground
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sections was conducted under the combined sponsorship of the Portland Cement
Association (PCA), ACPA, and the International Grooving and Grinding Association
(IGGA) (73). This project, titled “The Longevity and Performance of Diamond-Ground
Concrete Pavements,” focused on evaluating the performance of diamond ground
sections located all over the United States. Specifically, the database of projects used in
this study was compiled from the following data sources:
- Field surveys were conducted at 60 pavement sections in 18 states.
- Performance data for 133 sections were obtained from an earlier study on
diamond grinding performance (74).
- SPS-6 data from the LTPP database.
The following conclusions were gleaned from the research (73):
- CPR with diamond grinding is an effective means of extending the service life of
concrete pavements.
- Diamond grinding significantly increases surface texture, and the resulting level
of smoothness is comparable to that of a new HMA pavement or overlay.
- The long-term effectiveness of diamond-ground pavement greatly depends on the
condition of the existing pavement structure and the level of CPR applied.
Overall, this study found the performance of diamond ground pavements to be excellent.
The results of a service life, faulting, and surface texture analysis showed that a diamond
ground surface may be expected to provide about 10 years of service, at which time the
pavement may be reground to provide additional service life (73). A cracking analysis
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showed that a pavement slab could be reground up to 3 or 4 times without compromising
fatigue life.
“Effectiveness of Tire/Road Noise Abatement Through Surface Retexturing by
Diamond Grinding for Project SUM-76-15.40”—In Ohio, a bituminous asphaltic
concrete (BAC) portion of I-76 was reconstructed with PCC with a random transverse
grooved surface. Upon this switch, residents nearby the roadway perceived a noticeable
increase in tire/road noise. Prompted by the experiences encountered on this construction
project, this research project commenced with the objective of quantifying traffic noise
differences due to re-texturing the concrete pavement surface through diamond grinding.
Specifically, this research includes the tasks of collecting traffic noise level and
frequency data, identifying traffic noise level and frequency differences due to the re-
texturing of the pavement surface, and identifying traffic noise level and frequency
differences due to the re-texturing that correlate with distance from the source.
There are two ongoing diamond grinding research studies being undertaken by the Missouri
DOT:
Evaluation of Diamond Grinding on New PCCP (Missouri DOT)—In 1997, the
Missouri Department of Transportation began research that focused on determining the
benefit associated with diamond grinding new PCC pavements. The study was triggered
by the belief that “the smoother a pavement is initially, the better it’s going to perform
over time and the longer it is going to last” (75). To study this concept, two projects on
Route 60 in Butler County, Missouri were constructed in 1997 by the same contractor,
with the same equipment, and using the same materials. The only design difference
between the two projects is the fact that one was transversely tined, and one was diamond
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ground within 1 month of construction. A 2000 Missouri DOT report provided a project
update after 3 years of construction. Both of these projects continue to be monitored
annually.
Evaluation of the Combination of Undersealing and Diamond Grinding (Missouri
DOT)—In recent years, the Missouri Department of Transportation has conducted
research to investigate the effectiveness of using the combination of undersealing and
diamond grinding as a preventive maintenance technique. The study focused on
monitoring the performance of three in-place pavements that received this treatment
combination in 1985, 1992, and 1996, respectively. A general conclusion of this report is
that this treatment combination “can be an effective CPR technique under the right
conditions” (76). A 2000 Missouri DOT report provides much more detailed information
about this particular study.
Undersealing. While there has not been much recent published information regarding the
effectiveness of undersealing as a preventive maintenance treatment, a 2001 short report by
Barron does discuss the advantages of using polyurethane as an undersealing material (77).
According to Barron, “undoubtedly, some of the poor performing undersealing projects in the
past were most likely due to shortcomings associated with the cementitious grouts that have been
used historically.” Examples of past problems with cementitious grout compositions include
poor performance when subjected to vibratory conditions, shrinkage due to drying, little or no
tensile strength, and the fact that they are rarely cured to full strength before being reintroduced
to traffic.
In recent years, more usage of medium and high density expanding polyurethane materials
has been observed. According to Barron, the polyurethane materials have provided “much
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improved results over the previously used cementitious grout” (77). As a result of these material
advancements, Caltrans now includes the polyurethane process in their Special Provision
Specifications, and Texas DOT, New Mexico DOT, and at least 30 other states are now using
this technology (many with state-wide service contracts) to more effectively and economically
maintain safe, smooth pavements.
Specifications
Traditionally, preventive maintenance treatments have been constructed using material or
method specifications. Such specifications verify the material physical properties and
construction methods, but do not necessarily address the field performance (78). In recent years,
there has been a movement toward making the contractor be more responsible for the
performance of the applied maintenance treatment with the use of performance-related
specifications (PRS) and warranties. This section introduces the concepts of each and
summarizes some of the initial work being done in these areas.
Performance-Related Specifications (PRS)
With PRS, contractor pay is based on the projected future performance of a constructed
treatment (i.e., future pavement performance). Future performance is predicted using distress
models that have key construction quality measurements (i.e., sample test results) as inputs. A
number of PRS-related studies were located as part of the literature search. The following
summarize these some of these recent studies on the topic of PRS for maintenance treatments.
Performance-related specifications have recently been proposed for conventional chip
seals. One test that is expected to be included in a PRS for chip seals is the new sweep
test. The sweep test is a refinement of the abrasion-cohesion test developed by ESSO in
France, and is similar to the wet track abrasion test (78). In the test, a chip seal sample
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(applied to a circular piece of roofing felt) is subjected to a rotating nylon brush attached
to a commercial grade kitchen mixer. After one minute of subjecting the chip seal to the
rotating brush, the mass loss is recorded and plotted versus time. This test has shown
promise as a performance-related specification test for chip seals and has been found to
be much more effective that the demulsibility test.
A new process has also been developed by the Rocky Mountain User Producer group for
emulsion cold in-place recycling (CIR) that includes innovative emulsion chemistry and
performance-related specifications (78). This PRS includes a new test for raveling, and
testing for thermal cracking, strength, and moisture susceptibility.
The ongoing Caltrans-managed pooled fund study on slurry systems is likely to generate
tests and design procedures that can be adapted to performance-related specifications for
slurry seals and microsurfacing.
Performance Warranties
Product performance warranties are guarantees by a contractor that a certain level of service
will be maintained on a roadway for a specified period of time after the placement of a
maintenance treatment. Performance warranties may extend to warranties on materials and
workmanship, or a warranty on the final product. As more agencies try warranties for pavement
preservation projects, two issues to consider are the mixing of prescriptive specifications with
warranties (which inevitably results in a dilution of the strength of the warranty) and project
selection (which, if not done properly, may either raise the project costs or put the contractor at
undue risk). Although the concept of a performance warranty on pavements is relatively new, a
few agencies have reported some experience in this area.
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Michigan Department of Transportation. In 1997, the Michigan Department of
Transportation (MDOT) initiated the use of warranties on its preventive maintenance
projects. The warranty periods were specified to be a portion of the expected service life
of the preventive maintenance treatment (6 to 10 years for most treatments), and were
intended to last long enough to ensure that premature failures related to construction
problems were covered. Chip seals, microsurfacing, slurry seals, crack sealing, and
concrete joint resealing were designed to have a warranty period of 2 years, whereas 3-
year periods were applied to nonstructural AC overlays, cold milling and AC overlays,
and concrete pavement repairs (79). Initially, contractors were concerned that MDOT
would expect treatments to be placed on pavements in poor condition, thereby making it
difficult for the contractor to meet the condition requirements specified in the warranty.
To assure the contractors that they would only be expected to apply preventive
maintenance treatments on good candidate projects, a process was initiated in which the
contractors were provided with a list of upcoming projects and invited to identify to
MDOT those that were not suitable candidates. The innovative warranty process initiated
in Michigan was designed to ensure that the contractor was responsible for quality
control of workmanship and materials, and not responsible for project selection or design.
California Department of Transportation. In an effort to protect the state investment
from early failures, the Caltrans Division of Maintenance initiated a warranty pilot
program in 2000 using guidelines established for preventive maintenance projects (80).
In the short term, Caltrans plans on evaluating existing warranted projects for benefits
provided, as well as implementing additional warranties on approximately 10 to 15
percent of new preventive maintenance projects. The long-term plan is to develop multi-
year (5-Year) warranty specifications within the capital rehabilitation program that can be
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used on all preventive maintenance projects that meet existing guidelines. Caltrans is
also evaluating the effectiveness of materials and workmanship warranties, and is
considering combining performance requirements with minimum quality requirements.
Arizona Department of Transportation. An active research project co-sponsored by
FHWA and ADOT is investigating the use of warranties on highway construction
projects. This study was initiated by ADOT after a number of chip seal projects were
found to be performing worse than expected. Under this project, the specifications, test
procedures, and performance requirements were developed for ADOT implementation.
The first warranty project (using a 2-year warranty) was successfully constructed in the
fall of 2002.
SUMMARY
This chapter presents information collected about recent pavement preservation and
preventive maintenance research as part of a literature review and search of current databases.
The literature search conducted under this project focused on identifying and reviewing
published documents summarizing recent (i.e., most within the past 10 years) pavement
preservation-related research activities in North America. Brief descriptions of notable
documents located in the literature search are provided, and organized into the following general
categories:
Treatment selection procedures/guidelines.
Treatment timing.
Innovative materials and construction techniques.
Materials selection and mix design.
Treatment performance.
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Specifications.
The research summaries presented in this chapter document the past pavement preservation-
related research, but they do not document current agency research needs and interests. Current
agency pavement preservation needs and interests are identified from the survey that was
developed and distributed as part of this project. By considering the agency responses to the
survey and completed research, future needs can be identified and prioritized. These research
needs and priorities are discussed in more detail in Chapter 4.
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CHAPTER 4. PAVEMENT PRESERVATION RESEARCH NEEDS
INTRODUCTION
Inherent to this project’s objective of identifying and documenting pavement preservation
research needs is the assumption that there is a need for research on pavement preservation and
preventive maintenance: the null hypothesis is that those who are involved in pavement
preservation practices either have all the information necessary to manage successful programs,
or are in the process of generating that information. In this chapter, pavement preservation
research needs are examined and recommendations for future research are offered. The
identification of research needs is approached by considering the following:
Research needs expressed in response to the project questionnaire.
Previously identified research needs.
Identified gaps between past/ongoing research and identified research needs.
PREVIOUSLY IDENTIFIED RESEARCH NEEDS
In the past 5 years there have been several initiatives to identify research needs or problem
statements on pavement preservation and preventive maintenance. These initiatives, championed
by groups such as the FHWA, Transportation Research Board, and the Foundation for Pavement
Preservation, are briefly discussed below.
Maintenance Research Master Planning Workshop (2000)
In conjunction with the 2000 Annual Meeting of the Transportation Research Board (TRB),
on January 13, 2000 a Maintenance Research Master Planning Workshop was held in
Washington, DC (81). Participants were tasked with reviewing TRB maintenance committee
(TRB Section A3C00 Maintenance) research problem statements, and recommending up to five
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projects in each of three categories: 3-year, 5-year, and 10-year phased research timeframes.
Note that there are only two committees within the twelve-committee Maintenance
group―Pavement Maintenance (A3C05) and Sealants and Fillers for Joints and Cracks
(A3C13)―which are relevant to pavement preservation.
The TRB’s Pavement Maintenance Committee provided four research statements:
Distillation of Polymer Modified Asphalt Emulsions.
Emulsion Treated Mix Design Procedure.
Cold Applied Transverse Crack Sealants for Asphaltic Pavements.
Micro-Surfacing Quality Assurance.
TRB’s Sealants and Fillers Committee provided ten research statements, but only one has any
bearing on pavement preservation:
Influence of Sealing Transverse Contraction Joints on the Overall Performance of
Concrete Pavements.
The results of the workshop were organized into immediate needs and research needs in the 1- to
3-year, 3- to 5-year, 5- to 10-year, and “other” (the “other” category includes identified needs
that were not prioritized within the 10-year period by the workshop participants). The Sealing
Transverse Contraction Joints problem statement identified above was recommended for
submission to NCHRP for consideration by AASHTO’s Standing Committee on Research
(SCOR) as an immediate need. Two other pavement preservation-related projects were
considered, both in the 5- to 10-year timeframe:
Distillation of Polymer Modified Asphalt Emulsions.
Emulsion Treated Mix Design Procedure.
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Foundation for Pavement Preservation (2001)
A 2001 report by the Foundation for Pavement Preservation, Pavement Preventive
Maintenance Guidelines, builds on the 34 responses to a survey that was distributed to the
members of the AASHTO Subcommittee on Maintenance (82). The report details steps
necessary to implement a pavement preventive maintenance program, including overcoming the
barriers to the development or implementation of a pavement preventive maintenance program.
Research needs that are identified to help to address these barriers include the following:
Educating the public about the benefits of preventive maintenance.
Fostering and strengthening management support.
Generating data to support and promote the advantages of pavement preventive
maintenance programs.
Guidance on project selection, treatment selection, and treatment timing.
More emphasis on performance monitoring to identify what works and what doesn’t.
Caltrans Workshop (2001)
In June 2001, California Department of Transportation (Caltrans) hosted a workshop co-
sponsored by the FHWA, AASHTO, and FP2 to develop research problem statements on
pavement preservation (83). An initial list of 50 research needs was generated and then, for a
smaller group of topics, problem statements were developed and grouped into the following
categories:
Construction practices.
Materials selection and mixture design.
Treatment strategies and selection.
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Performance evaluation.
Training.
Policy.
A somewhat subjective balloting process was used to develop the recommended research
problem statements, in that workshop participants voted on whether they supported the proposed
topics, and those that received few votes were then discussed. If additional discussion did not
identify a strong champion for the topic, it was eliminated from further consideration. The
remaining projects were then prioritized based on votes by the group, and a list of the top 22
projects was developed. The prioritized list of research problem statements is identified in
table 3.
Strategic Highway Research (2001)
A report on future strategic highway research (commonly referred to as F-SHRP) was issued
in 2001 (84). This report summarizes the activities of a committee charged with developing a
research program to address “strategic highway research needs.” The committee identified four
strategic focus areas for research, with associated goals:
Renewal—Developing a “consistent, systematic approach to performing highway
renewal that is rapid, causes minimum disruption, and produces long-lived facilities.”
Safety—Preventing or reducing the severity of highway crashes through more accurate
knowledge of crash factors” and through the application of selected, cost-effective
countermeasures to address those factors.
Reliability—Providing “highway users with reliable travel times by preventing and
reducing the impact of nonrecurring incidents.”
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Table 3. Prioritized research projects (83). Category Research Problem Title Objective
1.1 QC/QA for Pavement Preventive Maintenance Treatments
Develop QC/QA methodology for preventive maintenance treatments
1.2 Standardized Field Sampling Methods for Slurry Seal and Microsurfacing
Evaluate current practices and develop standards
1.Construction
1.3 Use of the Ignition Oven to Determine Percentage of Asphalt Concrete in Slurry, Microsurfacing, and Other Emulsion Mixes
Develop a standard method for determining the percentage of asphalt concrete for preventive maintenance treatments
2.1 Development of a Cost-Effective Chip Seal System for Pavement Preservation
Document best practices for design of chip seals
2.2 Concrete Materials for Maintenance Applications Document best practices for use of PCC materials
2.3 Performance and Specifications of Crack and Joint Sealants
Document effectiveness of seals and develop criteria for evaluating seals
2. Materials Selection and Mix Design
2.4 Mix Design Procedures, Engineering Properties, and Performance Characteristics of Emulsion Mixes With and Without RAP
Develop an improved mix design procedure for emulsion mixes
3.1 Timing of Preventive Maintenance Applications to Effectively Extend Pavement Service Life
Evaluate the benefits of timely pavement preservation strategies
3.2 Maximizing Pavement Preservation Strategies Through Cost Effectiveness Research
Evaluate the cost effectiveness of pavement preservation strategies
3.3 Appropriate Maintenance Treatments for Urban Areas
Identify the most appropriate treatments for urban areas
3.4 Development of Preventive Maintenance Guidelines for Pavement Blow-Ups
Document best practices for maintenance of blow-ups
3. Treatments and Selection Strategy
3.5 Development of Integrated Databases to Make Pavement Preservation Decisions
Inventory existing database systems for making pavement preservation decisions
4.1 Guidelines for Effective Maintenance Treatment Evaluation Test Sections
Develop a set of guidelines for evaluating preventive maintenance treatments
4.2 Performance Measures/Criteria for Conventional and Warranteed Preservation Treatments
Identify performance measures for various preventive maintenance treatments and guide specifications
4.3 Treatments and Quantification for Noise Reduction and Improved Surface Characteristics
Quantify the noise reduction and improved surface characteristics for preventive maintenance treatments
4.Performance
4.4 Documentation of Pavement Performance Data Based on the Application of Pavement Preservation Strategies
Develop procedures for collecting and documenting performance data
5.1 Design and Construction of High Quality Preventive Maintenance Treatments
Provide training on design and construction of preventive maintenance treatments
5.2 Training and Certification of Technicians Improve the skill level of technicians
5. Training
5.3 Training to Present the Results of R&D and to Facilitate Implementation
Early implementation of research findings
6.1 Innovation in Preventive Maintenance Through Performance-Based Specifications
Develop performance-based specifications for all types of preventive maintenance treatments
6. Policy
6.2 Implementation Guidelines for a Pavement Preservation Program
Develop guides for agencies wishing to develop pavement preservation programs
7. Other 7.1 Effectiveness of Retrofit Edgedrains Document current practices and develop improved guidelines for design, construction, and maintenance
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Capacity—Developing “approaches and tools for systematically integrating
environmental, economic, and community requirements into the analysis, planning, and
design of new highway capacity.
The two research areas which pavement preservation is most likely to be a part of are
renewal and safety. The report’s discussion of renewal identifies two objectives:
To achieve renewal that is performed rapidly, causes minimum disruption, and produces
long-lived facilities.
To achieve such renewal not just on isolated, high-profile projects, but consistently
throughout the highway system.
The need for additional renewal-related research and development is identified in the following
areas: performance-related specifications for new technologies, efficient construction equipment
and methods, nondestructive, real-time sensing, use of modular or prefabricated construction,
and use of advanced computing technologies (84). While pavement preservation is not singled
out, it should be a part of a plan that is intended to achieve rapid, long-lived, minimally
disruptive system renewal.
The discussion of safety identifies the following two objectives:
To identify more accurately the contributions of various factors to highway crashes,
fatalities, and injuries.
To determine the cost-effectiveness of selected countermeasures in preventing or
reducing the severity of highway crashes.
Pavement preservation could be incorporated as part of the second objective, but the types of
countermeasures envisioned do not include improving surface characteristics such as friction.
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Infrastructure Research and Technology Stakeholder Workshop (2002)
The FHWA held an Infrastructure Research and Technology Stakeholder Workshop in Fall
2002. The results are presented in a report by Pope, in which the goals of the program are
identified as enhancing mobility and productivity, extending the life of pavements and bridges,
and improving safety and performance (85). The workshop included break-out groups on
pavements and asset management, but neither pavement preservation nor preventive
maintenance were specifically addressed.
Survey of AASHTO Member Agencies (2003)
In 2003, a survey of AASHTO member agencies pavement preservation research activities
was developed for the FHWA’s Pavement Preservation Expert Task Group (PPETG). The
survey was distributed to the 50 states and 10 Canadian provinces; 49 states and 4 provinces
responded. Survey recipients were asked to report on their activities relative to the twenty-two
research statements developed at a FHWA/FP2 workshop in 2001. They were asked to report on
whether research was complete, in progress, planned, or whether they were interested in that
research topic. The responses to the first three questions shown in table 4 suggest that there is a
great deal of research either completed or in progress. However, this is likely to be misleading
because where more detailed feedback was provided the responses often suggest that all
pavement-related research was being reported on, including such topics as post-tensioned
prestressed concrete pavements, full-depth recycling, and moisture conditions in and below
open-graded shot rock base. The response to the fourth question, about interest, is more likely to
be a representative indicator of research needs.
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Table 4. Summary of 2003 PPETG survey results.
Problem Area Research Problems Complete In progress Planned Interested 1.1 QC/QA 6 4 1 28 1.2 Standard Field Sampling
4 3 2 21 1.Construction
1.3 Ignition Oven 4 1 3 22 2.1 Chip-Seal 6 7 5 29 2.2 Concrete for Maintenance
7 13 2 21
2.3 Crack & Joint Seals 10 14 3 29
2. Materials Selection and Mix Design
2.4 Emulsion Mix Design 5 5 5 24 3.1 PM Timing 5 10 4 26 3.2 Cost Benefit Testing 4 6 6 23 3.3 Urban PM Treatments 2 4 3 25 3.4 Pavement Blow-ups 2 2 4 22
3. Treatments and Selection
Strategy
3.5 PM Decision System 5 9 5 26 4.1 Guidelines 6 4 4 22 4.2 PM Measures 4 9 2 25 4.3 Improved Surface 6 8 3 20
4.Performance
4.4 PM Performance 4 7 6 24 5.1 PM Design and Construction
2 6 2 24
5.2 Technician Certification
5 7 3 19
5. Training
5.3 How to Implement Research
2 6 3 20
6.1 Performance Specifications
3 6 4 29 6. Policy
6.2 Implementation Guidelines
4 4 5 23
7. Other 7.1 Retrofit Edge drains 9 4 2 20
TRNews Issue on Highway Infrastructure Preservation (2003)
The September−October 2003 issue of TR News is devoted to Highway Infrastructure
Preservation, and includes a number of articles about pavement preservation (86). Gee and
Mueller identify the following directions for research:
Assistance in applying the right treatment to the right road at the right time.
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Research “to address the research, development, and technology needs of the nation’s
transportation departments.”
Research “to meet the safety, efficiency, and mobility requirements of the public.”
Larson, Scofield, and Sorenson, in “Research Frontiers in Pavement Preservation,” discuss
the need for a greater emphasis on pavement surface characteristics. Research needs that they
identify include the following:
Improved guidelines and incentives for obtaining desirable levels of critical surface
characteristics.
Improvements in the measurement and evaluation of overall smoothness, the detection of
bumps, and the identification of roughness that would increase dynamic loading impacts
from trucks.
Improved guidance on the desirable macrotexture to reduce splash and spray and
hyrdroplaning and on the microtexture to increase friction at low and high speeds.
Measures of the overall benefit of increased texture and friction on reducing fatalities,
injuries, and the resulting traffic delays.
Performance measures to help monitor whether texture and friction levels on the network
are increasing as a result of construction or preservation activities.
Many other shortcomings are identified, but not specifically identified as research needs.
These include issues associated with surface appearance, evaluation technologies, and surface
noise.
The various initiatives discussed above show that a broad range of research needs have been
previously identified. If any generalized conclusion can be drawn, it is perhaps that the research
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needs identified by workshops and researchers are somewhat reflective of their own interests and
priorities, while those identified by agency surveys better reflect what the agency feels is needed
to improve their programs (provided that the right respondents are completing the surveys).
RESEARCH INTERESTS AND NEEDS IDENTIFIED IN THE 2004 PAVEMENT PRESERVATION SURVEY
The pavement preservation survey conducted under this project provides useful input for
establishing a national agenda for pavement preservation research. Within this survey, a number
of questions were used to assess the past, current, and planned pavement preservation-related
research activities of the responding agencies, and to generally assess their research interests and
needs. Some questions directly ask the responding agencies to describe their research needs and
interests; the answers to many other questions are interpreted to identify common needs by most
responding agencies. The remainder of this section discusses general observations and specific
research needs identified in the 2004 survey.
The survey tool used in this project was developed by reviewing research needs previously
identified and documented in conducted workshops, surveys, and published reports; this
generated a working list of research topics and categories upon which to build. During the
development of the survey, a review of previously identified research topics found that most
could be divided into the following general categories:
Specifications.
Materials selection and mix design.
Treatments and strategy selection.
Construction.
Treatment performance.
Others (miscellaneous topics).
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In Question 3 of the survey, the respondents were asked to express their interest in a series of
previously identified preservation-related research needs. For each of the topics included in
Question 3, respondents were asked to identify if they had conducted past research, were
conducting ongoing research, had plans for future research, and if they had any interest in the
research being conducted by other agencies. The specific responses to this question
(summarized in table B-4 in Appendix B) indicate interest or research in a wide range of topics.
In addition to providing an explanation of their agency’s past, current, and future
involvement with different research topics, respondents were also asked to rate their “interest” in
each topic by rating each topic on a scale of 1 to 10, where 10 signifies very high interest and 1
signifies very low interest in a topic. Note that these are individual interest ratings and not
comparative rankings of different topics (i.e., a respondent could assign a 10 to every topic in
which there was a strong interest). A summary of these rankings is presented in table B-5, and
repeated below in table 5.
The following are the five research topics with the highest average interest rankings (note the
computed average interest rankings are included in parenthesis):
1. Treatment impact on pavement performance (e.g., extension of service life) (8.1).
2. Economic evaluation of treatment effectiveness (7.9).
3. Development/enhancement of treatment selection guidelines (7.6).
4. Construction and monitoring of treatment test sections (7.6).
5. Investigation of optimal treatment timing (7.6).
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Table 5. Summary of interest ranking averages and an overall ranking of Topic IDs based on interest.
Top
ic ID
Research Area/Topic
Weighted Average of
Interest Rankings1
Prioritized Ranking of Computed Average Interest
Rankings SPECIFICATIONS 1. Treatment QC/QA specifications 6.5 12 2. Treatment performance-related specifications (PRS) 5.9 17 3. Warranties for treatments 6.1 15 MATERIALS SELECTION/MIX DESIGN 4. Binder and aggregate tests and procedures 5.8 18 5. Crack and joint sealant material studies 6.0 16 6. In situ pavement property investigations to improve mix/treatment design 6.2 13 TREATMENTS AND STRATEGY SELECTION 7. Characteristics of candidate pavements for preventive maintenance 7.4 6 8. Development/enhancement of treatment selection guidelines 7.6 3 9. Investigation of optimal treatment timing 7.6 5 10. Economic evaluation of treatment effectiveness 7.9 2 CONSTRUCTION 11. Factors that affect treatment performance (surface preparation, tack coats,
weather, and so on) 7.0 10
12. Innovative treatment construction techniques/equipment 6.9 11 13. Innovative field sampling and testing methods for treatments 5.8 19 TREATMENT/PAVEMENT PERFORMANCE 14. Construction and monitoring of treatment test sections 7.6 4 15. Analysis of historical data to investigate treatment performance 7.4 7 16. Treatment impact on noise, friction, and smoothness 6.2 14 17. Treatment impact on pavement performance (e.g., extension of service life) 8.1 1 18. Performance measurements/criteria for preservation treatments 7.1 9 OTHERS 19. Training and certification of technicians 4.9 21 20. Integration of preventive maintenance and pavement management 7.3 8 21. Standardization of pavement preservation-related definitions 5.5 20 1 Rated from 1 to 10, with 10 indicating the greatest interest.
Considering the average interest rankings by interest “category” (i.e., Specifications, Materials
Selection/Mix Design, Treatments and Strategy Selection, etc.), there is the greatest interest in
the topics of Treatments and Strategy Selection and Treatment/Pavement Performance; the least
interest is in topics associated with Specifications and Materials Selection/Mix Design.
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ASSESSMENT OF CURRENT RESEARCH NEEDS
To identify and document current pavement preservation research needs, the following
sequential process was used:
1. Conduct a literature search of completed and ongoing research initiatives to determine
what has already been studied.
2. Review past identified research needs and problem statements and use them as a basis for
developing the 2004 pavement preservation survey.
3. Review the responses to the 2004 pavement preservation survey to assess the current
needs of responding agencies.
4. Compare the past and ongoing research topics identified in the literature search to the
research needs identified in the 2004 pavement preservation survey to determine those
topics that still need additional research.
The results of the literature search are summarized in Chapter 3, and give a good indication
of the past and current research interests. The research needs and problem statements that are
discussed in this chapter provide an overview of the topics of interest that have been identified
both by pavement preservation industry leaders and state highway agencies over the past 5 years.
The responses to Question 3 of the 2004 survey provide a starting point for the assessment of
current research needs. Based on the survey responses and, to a lesser extent, the ongoing and
completed research, research needs can be generally categorized as follows:
Sharing information between agencies.
Materials selection and mix design.
Selection of treatments and treatment strategies.
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Construction.
Treatment performance.
Specifications.
Policies and training.
In this section the “gaps” between the research needs identified in the survey, and the past
and ongoing research identified in the literature review are identified; obvious gaps between the
two indicate a need for future research. The recommendations for future research are then
prioritized (as low, medium, or high priority), based on rankings provided by the agencies who
responded to the 2004 survey and the authors’ subjective rankings of the topic’s significance.
Information Sharing
There is a wide range of pavement preservation experience among SHAs. Where some have
comparatively established programs, others are still in the early stages (Questions 5b and 5c).
Where some agencies identify obstacles, others report that they have effectively overcome the
very same obstacles (Question 8). The answers to Question 9 identify obstacles that agencies
report facing, along with the actions that were taken to address the obstacles. And in Questions
24 and 25, agencies share treatment-related success stories and failures.
SHAs clearly have a large amount of knowledge and experience to share. However, it is
equally clear that information sharing practices can be improved. While 26 percent of the
respondents (9 of 35) to Question 1 said that they were “very familiar” with the research being
conducted by other agencies, 48 percent indicated that they were only “somewhat familiar” with
such research, and the remaining 26 percent categorized themselves as having only “minimal
knowledge” of the research activities of other agencies. Question 2 asks if knowing about the
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research performed by others would impact the research undertaken by their agency, and 90
percent of the respondents said that it would.
While the benefits of sharing information do not constitute a particular “research” need, they
do indicate that improved sharing of pavement preservation ideas, practices, and results between
agencies is desirable. Forums for such information sharing are already being developed. One
example is the Midwest Pavement Preservation Partnership, a consortium of 11 Midwest SHAs
that serves as a regional forum for sharing information and experiences. Similar partnerships are
under development in the southeast and northeast and should be supported. Given the variation
in the status of programs, environments, materials, and so on from region to region, these should
be most helpful when they reflect regional needs and interests.
Materials Selection and Mix Design
In the 2001 publication Pavement Preservation Research Problem Statements, this research
category is described as the ”evaluation of a variety of preventive maintenance treatments and
development of improved systems, mix design methods, and specifications” (83). At the 2001
workshop reported on in this publication, the following four materials selection and mix design-
related research objectives were identified (83):
Consolidate and review the best practice chip seal design procedures for asphalt
emulsions, including determining the rheological properties of the binder and mix design
characteristics of the system.
Document best practices for use of PCC materials in maintenance applications (i.e., full-
depth slab repair, full- and partial-depth repairs, and dowel bar retrofit).
Document the effectiveness of crack and joint sealant materials.
Develop a mechanistic-based mix design procedure for asphalt emulsion mixes.
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Question 3 of this project’s survey asked responding agencies to describe their research history
and current interest in the following three materials selection and mix design-related topics:
Binder and aggregate tests and procedures.
Crack and joint sealant material studies.
In situ pavement property investigations to improve mix/treatment design.
The Question 3 responses are summarized in table 6.
Table 6. Summary of interest in materials selection and mix design-related research topics as indicated in the 2004 pavement preservation survey.
Number of Agencies
Materials Selection and Mix Design-Related Topics
Past or Ongoing Research
Plans for Future
Research
Interest in Research by
Other Agencies
Prioritized Ranking of Computed Average Interest
Rankings Binder and aggregate tests and procedures 15 4 21 18 Crack and joint sealant materials studies 20 7 24 16 In situ pavement property investigations to improve mix/treatment design
17 5 24 13
The responses indicate that current interest in material selection and mix design-related
topics is relatively low (i.e., prioritized rankings of 18, 16, and 13 out of 21 topics), perhaps
because many agencies have participated in past or ongoing research studies on these topics.
Based on the results to Question 3, the greatest amount of past and ongoing research is
associated with the subject of crack and joint sealant materials studies. Of the responding
agencies, 57 percent (20 of 35) indicated some past or current research activities related to this
subject, 20 percent (7 of 35) indicated future plans for sealant related research, and 69 percent
(24 of 35) were interested in the research activities by other agencies on this subject.
The literature review also identified over 10 relatively recent and ongoing agency studies
which include a comparison of sealant materials in their scope. The most significant national
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research on this subject is that conducted under the SHRP-106 and FHWA Long-Term
Monitoring Crack and Joint Sealant Studies (35,36,61,62). In addition to national studies on the
subject, many individual agencies have conducted their own sealant-related research. Specific
examples of such research include studies in Ontario and Michigan (37,39) and research in
progress in Virginia, Montana, Ohio, Texas, and North Dakota. A national study, Cost
Effectiveness of Sealing Transverse Contraction Joints in Concrete Pavement, began in 2003 as
part of FHWA’s CPTP program.
A second area of material-related interest is improving mix design methods for thin surface
treatments for bituminous-surfaced pavements. Here ”surface treatments” is used as a generic
term which includes treatments such as chip seals, microsurfacing, slurry seals, fog seals, thin
HMA overlays, and the like. In Question 3 of the 2004 survey, 37 percent (13 of 35) of the
responding agencies indicate completed research related to the topic of “in situ pavement
property investigations to improve mix/treatment design.” Another 29 percent (10 of 35)
indicate that they were either conducting ongoing research on the subject or had plans for
conducting future research. Supporting this, n the recent literature there are a number of projects
that not only investigate the observed performance of different treatments, but also focus on
improving treatment design processes. Examples of past research studies with that additional
focus include work on chip seals (5, 50, 51), slurry seals, and microsurfacing (5,51).
There are also a number of ongoing research efforts that focus, at least in part, on improving
the design of thin maintenance surfacings. These include the following: National Sealer Binder
Study (FP2, FHWA, Arizona DOT), “Analyze Existing Fog Seal Asphalts and Additives” (Texas
DOT), “Slurry/Micro-Surface Mix Design Procedure” (FHWA Pooled Fund Study), and
“Optimizing Gradations for Surface Treatments” (North Carolina DOT).
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At the same time, several agencies have documented their improved thin surfacing design
and associated construction practices, as evidenced by the mergence of manuals of best practice
for treatments (e.g., Minnesota’s Seal Coat Handbook), or treatment-related procedures included
in detailed preventive maintenance program guidelines. The reference manual for the NHI
pavement preservation course, Design and Construction of Quality Preventive Maintenance
Treatments, also include materials selection and mix design information for the typical preventive
maintenance treatments.
A third material-related topic of potential interest is documenting best practices for the use of
PCC materials in maintenance applications, such as full- and partial-depth repairs and dowel bar
retrofit operations. No direct feedback on this subject was received as part of the 2004 survey as
this specific topic was not included in Question 3. And while responding agencies had the
option to include “other” topics of interest, there are no responses indicating that there is a strong
interest in this research area. The literature search supports this lack of interest; the only recent
research reports particularly relevant to this topic was the final report for the LTPP Pavement
Maintenance Materials: PCC Partial-Depth Spall Repair Experiment, and the corresponding
manual of practice that was based on the findings from this experiment (87, 88). These
references collectively describe an investigation of a number of different repair materials, and
provide best practice information for producing good quality partial-depth repairs.
Research Needs Assessment for Materials and Mix Design-Related Topics
The assessment of past and current research needs indicates that while most interest in
materials and mix design-related research has been in choosing the most effective sealant
material for crack and joint sealing, there is growing interest in improving the materials and
design procedures for thin surface treatments on bituminous surfaces. This conclusion is
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supported by both the interest indicated in the 2004 survey and the considerable amount of
current or recently completed research on these subjects. Accordingly, recommended future
research topics include the following:
Document the effectiveness of crack and joint sealant materials—While this has been
a high priority research topic in the past, the 2004 survey indicates the interest in this
research topic is lessening as the “crack and joint sealant material studies” topic only
received the 16th highest average interest ranking out of 21 research topics: perhaps
research on this topic is beginning to address agencies’ needs. As the performance of
sealant materials is specific to local climate conditions and preparation techniques, it is
anticipated that independent agency studies will continue to investigate this subject;
however, because this research need is beginning to be met as a whole, the priority for
this research topic is low.
Improving mix design methods for thin surface treatments for bituminous-surfaced
pavements—As individual agencies gain experience with thin surface treatments, more
research is needed to improve the mix design methods associated with those thin
treatments. Consider reported experience with chip seals: many agencies are now
focusing on improving or fine tuning their design and construction processes to improve
the overall performance of their chip seal treatments. It is believed that agencies will also
begin conducting similar research for other preventive maintenance treatments as they
gain experience with those treatments. Despite the relatively low level of interest by
agencies (this topic ranked 13th out of the 21 research topics included in Question 3 of the
survey [see table 5]), it is envisioned that the interest in this research topic will continue
to grow as more agencies gain experience with these treatments. The overall priority for
this research topic is medium.
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Documenting best practices for use of PCC materials in preventive maintenance
treatments on PCC pavements (e.g., full- and partial-depth repairs and dowel bar
retrofitting)—There is very little current interest in this research topic. The combined
results from the 2004 survey and the literature review indicate that the greatest interest is
in improving the processes associated with the more traditional preventive maintenance
treatments applied to bituminous-surfaced pavements (e.g., chip seals, slurry seals, and so
on). Based on this, the priority for this research topic is low.
Selection of Treatments and Treatment Strategies
Survey respondents expressed the greatest interest in treatment/strategy selection. Research
topics included in this category include:
Characteristics of candidate pavements for preventive maintenance.
Development/enhancement of treatment selection guidelines.
Investigation of optimal treatment timing.
Economic evaluation of treatment effectiveness.
Integration of preventive maintenance and pavement management.
Of the 21 topics identified in Question 3, these 5 are ranked in the top 8 based on all of the
responses. Responses to other survey questions support the high interest in this area. For
example, in identifying common obstacles to implementing pavement preservation (Question 8),
dealing with the shift away from worst-first project selection is identified as the most difficult
obstacle to overcome. Sixteen agencies are currently trying to address this and another seven say
that they will have to overcome it; only two say that they do not consider it an obstacle. The
significance of this obstacle is supported by the responses to Question 14, in which most
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preventive maintenance treatments are identified as placed on pavements in fair condition or
lower.
The responses to Question 18, which asks about the methods used to select a preventive
maintenance treatment, do not really indicate that this is a significant problem, although some of
the more “technical” approaches (such as preset schedule of times, use of a selection matrix, in-
house guidelines, and cost/benefit analysis) are not used as much as the least formal method
(engineering judgment).
Question 19 asks about the integration of pavement preservation and pavement management.
While 70 percent of the responses say these are integrated (23 of 33), 7 claim complete
integration, 7 are in the process of integration, and 8 are using in-house guidelines. The
responses to Question 20 (on the method used to time the placement of preventive maintenance
treatments) and Question 21 (on the use of a management system to optimize timing) further
support interest in this topic area.
Recent research also suggests that there is a high level of interest in the methods used to select
pavement preservation treatments. Reports that describe research or actual methods used to select
preventive maintenance treatments in Iowa, Michigan, Texas, and Ohio are identified in Chapter 3.
Examples of procedures used in Arizona, California, Kansas, Maryland, Michigan, Montana,
Pennsylvania, South Dakota, Washington State, and the Metropolitan Transportation Commission
(San Francisco Bay area) are also discussed in chapter 3. Several of these reports include a
discussion of the agencies’ efforts to integrate preventive maintenance treatments into their existing
pavement management system. In addition, several reports describe methods for selecting preventive
maintenance treatments (such as matrices and decision trees).
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There is also recent research on identifying the optimal time to apply preventive maintenance
treatments. A total of five studies are highlighted in chapter 3, including two published reports, one
published paper, and two ongoing studies).
Treatment Selection Research Needs
Based on the survey responses and the completed research, the following research topics are
identified. As a group, these topics are assigned a high priority.
Development/enhancement of treatment selection guidelines―Improved treatment
selection guidelines would address SHA-identified priority areas of interest, as well as
several of the obstacles to implementation. A range of different approaches to treatment
selection are being used, so research should focus on the advantages and disadvantages of
different treatment selection methods as well as methods for the development of such
guidelines. Although there is a fair amount of past and ongoing research on this topic,
this is the third highest ranked topic in responses to Question 3 of the 2004 survey. This
suggests that SHAs need further assistance in adapting national or regional research
results to their own agencies. Accordingly, this research area is assigned a priority of
high.
Investigation of optimal treatment timing―The survey identifies this as a topic of high
interest (ranked 5th out of 21 topics), and at least half of the respondents indicated that
they are not optimizing the timing of preventive maintenance treatments. Improving
treatment timing addresses issues such as shifting away from worst-first treatment
selection, showing early benefits of pavement preservation, and overcoming treatment
failures. With recently completed research on this topic, there is a great need to explore
implementation of the research findings. This includes both making agencies aware of
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the tools and methodologies that are available to evaluate optimal timing, and helping
them to implement those tools locally. The priority of this research topic is high.
Economic evaluation of treatment effectiveness―Many agencies report barriers to
successful pavement preservation programs that include obtaining the required funding,
demonstrating the benefits of the programs to upper management, and convincing the
public to accept treating roads in good condition (see the individual responses to
Question 9, summarized in table B-14). The documentation of the effectiveness of
pavement preservation, or the further development and refinement of tools to evaluate
effectiveness, would help to overcome these obstacles. Because of this topic’s
importance and the lack of past or ongoing research found in the literature review, the
priority for this topic is high.
Integration of preventive maintenance and pavement management―This topic
addresses issues of treatment timing, treatment selection, and treatment effectiveness.
The lack of integration adversely affects an agency’s ability to evaluate treatment
effectiveness, and may contribute to other agency-identified obstacles. While there are a
number of recent published papers that address this topic, and there is a new NHI
pavement preservation course that covers this topic, the potential impact of improvements
and the wide differences in individual agency approaches merits it a high priority.
Construction
Recent construction-related pavement preservation research can be grouped into the
following three areas:
Investigation of construction factors that affect treatment performance (e.g., surface
preparation, tack coats, weather, and so on).
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Development and implementation of innovative treatment construction techniques and
equipment.
Development of best practice manuals associated with preventive maintenance
treatments.
Question 3 of the 2004 survey asks agencies to summarize their past, current, and planned
research activities and interests, and the responses indicate little past or current research in
construction-related topics: for example, on the topic of investigating innovative treatment
construction techniques and equipment, only 17 percent reported (6 of 35) conducting research,
23 percent (8 of 35) are involved in ongoing research, and 17 percent (6 of 35) have plans for
future research. While no question specifically addressed developing best practice manuals for
preventive maintenance treatments, one responding agency did indicate a specific need for “Chip
Seal Best Practices.”
There are many published reports that describe field trials (i.e., documentation of the first usage
of treatments in a given agency), but very few of the published studies investigate methods or
procedures for ensuring the construction quality of preventive maintenance treatments. One
document that will soon be available on the subject is the reference manual associated with the latest
NHI pavement preservation course, Design and Construction of Quality Preventive Maintenance
Treatments. This document provides guidance on all aspects of the construction process, including
design considerations, construction steps and methods, recommended quality control procedures, and
troubleshooting information. Another useful resource is the Pavement Preservation Checklist Series
published by FHWA. This series of pocket-sized references summarize QC/QA checklists associated
with a number of pavement preservation treatments including crack seals, chip seals, thin hot-mix
asphalt overlays, fog seals, microsurfacing, and joint sealing of PCC pavements. Most of the
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information included in these checklists is also included in the Design and Construction of Quality
Preventive Maintenance Treatments course Reference Manual.
There do not appear to be many ongoing studies investigating “innovative treatment
construction techniques and equipment.” Only the findings from the recent international
scanning tour on pavement preservation describes construction techniques and methods that
agencies may not be familiar with (27). The small number of studies on the subject is not
surprising; many agencies are experimenting with preventive maintenance treatments for the very
first time, and for them the application of these new treatments is innovative in itself. Some agencies
with significant experience with certain preventive treatments have either recently published, or are
in the process of publishing, best practice guidelines for the design and construction of quality
preventive maintenance treatments (e.g., Minnesota’s Seal Coat Handbook). Other agencies, such as
Caltrans, Michigan DOT, and Ohio DOT, have incorporated many treatment design and construction
details into their pavement preventive maintenance program guidelines.
Research Needs Assessment for Construction-Related Topics
Based on the number of completed or ongoing studies related to the construction of pavement
preservation treatments, this is not a high priority research topic. The prioritized research topics
from Question 3 support this conclusion, as the three construction-related topics were found to
have only the 10th, 11th, and 19th largest average interest rankings out of the 21 presented topics
(see table 5). However, the Question 3 responses show that 80 percent of responding agencies
(30 of 35) are interested in the research being conducted by other agencies on both the topics of
“factors that affect treatment performance” and “innovative treatment construction
techniques/equipment.” So, while these results clearly show a strong future interest in learning
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new or improving current preventive maintenance construction techniques, the current priority
on conducting such construction-related research is low.
A summary of the recommended future construction-related research topics include the
following:
Investigation of construction factors that affect treatment performance—While there
is considerable interest in focusing on improvements to the construction process to
optimize treatment performance, for the most part it is premature for research efforts to
focus on this subject. Many documented treatment failures are still being attributed to
selecting the wrong pavement for a given treatment (see the results of Question 25 in the
survey) or applying the treatment at the wrong time. Therefore, the priority for this
research topic is low.
Development and implementation of innovative treatment construction techniques
and equipment—As stated above, many agencies still find the application of preventive
maintenance treatments to be innovative. While it is expected that there will be a limited
amount of research on this subject in the upcoming decade, the current focus by most
agencies is on trying different treatments and determining whether to include those
treatments in their pavement preservation program. The overall priority for this research
topic is low.
Development of best practice manuals associated with preventive maintenance
treatments—As agencies determine which treatments work best for their agency, the
need to formally document construction recommendations in a best practice manual
emerges. Because an important component of an established pavement preservation
program is the consistent documentation of treatment procedures and expectations, the
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priority for this research topic is medium. Agencies interested in developing such best
practice manuals, however, should take advantage of similar publications already
developed by other agencies.
Treatment/Pavement Performance
There is significant interest in research on how preventive maintenance treatments perform,
how treated pavements perform, and the effect of treatments on specific measures of pavement
performance. In fact, from Question 3, the effect of preventive maintenance treatments on
pavement performance was the highest ranked research topic. There is also significant interest
(fourth highest ranking) in constructing and monitoring treatment tests sections, as these could be
used to obtain information on treatment effects, timing, and performance.
Survey Question 22 asks whether agencies currently track the performance of their preventive
maintenance treatments, and almost half of the respondents (16 of 34) do not. The individual
responses indicate that much of the monitoring that is being performed is part of the pavement
management process and is not necessarily focused on preventive maintenance treatments. This is
borne out by the responses to Question 23, which asks whether agencies analyze the performance of
their preventive maintenance treatments. In addition to providing an indirect measure of how well
established pavement preservation programs are, the responses may also highlight research needs.
Fourteen respondents say that they have analyzed treatment data to estimate expected life, while 20
say that they have not. This also ties into the responses received to the potential obstacle identified in
Question 8, “showing early benefits.” Seven agencies say that they are currently facing this obstacle
and 10 others identify this as an obstacle that they expect to face; the rest of the responses state that
they have either overcome this obstacle or do not view it as a barrier.
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Responses to Question 25, which asks for experiences with treatment-related failures or
setbacks, provide another indication of research needs. Several respondents reported failures
with specific treatments, singling out microsurfacing, cold recycling, and hot recycling. Two
agencies said that budget rollbacks have impacted their ability to place treatments on good
candidate pavements. One agency related failures to poor project selection, while another related
the occasional failures to either poor construction techniques or material quality. Overcoming
treatment failures is also identified (in the responses to Question 8) as the second greatest
obstacle in implementing a pavement preservation program.
The issue of treatment performance and pavement performance is inextricably linked to
project selection and treatment timing, which is covered elsewhere in this chapter. However, in
considering the magnitude and significance of this issue, it is worthwhile to review some of the
related feedback discussed elsewhere. For example, Question 14 addresses the condition of
pavements receiving preventive maintenance treatments (approximately 65 percent of the
pavements are in fair, poor, or very poor condition), responses to Question 18 identify methods
used to select preventive maintenance treatments, and Question 20 asks about methods used to
time preventive maintenance treatment placement (12 responses that the treatments are placed
when distress reaches a medium severity level).
The importance of this topic to SHAs is undisputed. Chapter 3 discusses ongoing or
completed research on treatment performance, and this is by far the most researched topic. For
flexible pavements, at least five studies of LTPP SPS-3 and SPS-4 projects are cited.
Furthermore, 30 ongoing projects are identified in Chapter 3. These are primarily on the
following treatments: crack sealing and filling, chip seals, microsurfacing, slurry seals, sand
seals, sealer/rejuvenators, utlrathin surfacings, thin overlays, and open-graded friction courses.
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Eighteen ongoing or completed studies are identified for PCC-surfaced pavements, with most on
the topics of joint or crack sealing, dowel bar retrofits, and diamond grinding.
Based on the survey responses and the completed research, the following research topics are
identified. As a group, these topics are assigned a high priority.
Construction and monitoring of treatment test sections―Test sections are among the
best tools available to evaluate treatment performance and the effect of treatment
performance on pavement performance. While constructing, monitoring, and analyzing
the findings from effective test sections may be best done at the local level, a nationally
coordinated effort, perhaps through the F-SHRP program, could be used to address
specific concerns, such as the effect of pavement preservation treatments on safety and
noise. The priority of this research topic is medium at the national level, although
individual agencies that do not have extensive experience with pavement preservation
treatments would do well to make this a high priority.
Tools to measure preventive maintenance treatment/pavement performance―More
research is needed on the measurements of performance that reflect the benefits of
pavement preservation. Traditional measures of pavement performance, and certainly
those most associated with network monitoring as part of pavement management, are
closely associated with pavement failure (e.g., cracking, rutting, faulting). It is believed
that these measures do not always reflect the benefits of pavement preservation
treatments, but there certainly is not any consensus on what measures are more
meaningful. Many agencies would benefit from research to determine which
performance measures truly identify which performance characteristics to monitor to
assess if their pavement preservation goals are being met. For those agencies in the
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process of implementing a formal pavement preservation program, this research topic is
assigned a priority level of high.
Treatment impact on noise, friction, and smoothness―Related to the previous topic,
since preventive maintenance treatments are primarily intended to be used on pavements
with functional problems, more research is needed on the effect of various treatments on
functional performance. Such research would help to identify treatment benefits and also
address issues of treatment timing. This is a medium priority topic.
Treatment impact on pavement performance (e.g., extension of service life)―Many
surveys of treatment performance focus on how long a treatment lasts. This is
problematic for several reasons, including how treatment life is defined (for example, is
this until the treatment is no longer visible or until it is no longer effective?) and how to
measure the effect of the treatment on pavement performance. More research is needed
to investigate the impact of preventive maintenance activities on pavement performance
and expected pavement life. As both treatment and pavement performance is greatly
dependent on the time at which a preventive maintenance treatment is applied, it is
recommended that such research be investigated in conjunction with studies investigating
the impact of treatment timing on performance. This topic is rated high priority.
Performance measurements/criteria for preservation treatments―While noise,
friction, and smoothness are identified above as performance measures that are affected
by preservation treatments, it is noted elsewhere that these treatments are applied for
many other reasons, including sealing the pavement surface, reducing water infiltration,
and reducing the rate of pavement deterioration (Question 16). The identification of
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appropriate measures and criteria for measuring the performance of pavement
preservation treatments is a high priority research topic.
Specifications
The general heading of specifications includes three sub-headings: QC/QA specifications,
PRS, and warranties. Survey responses to Question 3 indicate lower than average interest in
these topics, and they also are ranked a lower priority than other topics. However, from survey
responses agencies are interested in improving their current treatment specifications. Question 26
asks about pavement preservation specifications, and while 12 respondents reported that they are
using up-to-date specifications for preventive maintenance treatments, another 12 said that their
specifications need improvement.
Question 27 asks about QC/QA procedures for preventive maintenance applications. Almost 70
percent of the respondents (24 of 35) said that they had such procedures in place for preventive
maintenance, while the remainder said they did not. However, in the additional provided comments
it appears as if many of these are actually talking about the conventional QC/QA practices in place
for HMA and PCC construction. Others indicated that the QC/QA procedures covered the materials
but not necessarily the construction of the treatments. Question 28 asks about the use of warranties
with preventive maintenance treatments, and only 7 of the 35 responding agencies had tried or are
using warranties. Many of those who hadn’t used warranties did express an interest in warranties or
intend to use them on some treatments in the future.
While the use of warranties is limited, the use of performance-related specifications is even more
limited. Only four agencies reported using them and three of the four only use them for a single
treatment.
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Despite interest in improving treatment specifications, there is little current interest in
moving from method specifications toward performance-related specifications or warranties for
preventive maintenance treatments. There are only a few published reports on each specification
type, including some work on tests for chip seals that are more related to performance and an
ongoing Caltrans-managed pooled fund study of slurry and microsurfacing systems. As more
agencies gain additional experience with preventive maintenance treatments, the interest in new,
innovative, quality-driven specifications is expected to increase. No studies of the effectiveness of
warranties were identified, and from the literature review only three agencies are identified as having
experience with warranties for preventive maintenance treatments.
Research Needs Assessment for Specification-Related Topics
There is interest in improved specifications, particularly for the more commonly used
treatments such as chip seals, crack and joint sealing, and microsurfacing. Performance-related
specifications and warranties represent an evolution toward more sophisticated specifications and
contracting practices, but require the greatest control of the materials and construction
procedures. Current or currently planned research in chip seal design and slurry systems may
address some of the immediate needs. Recommended future research topics include the
following:
Guidance on improved specifications for preventive maintenance treatments―This
research would address warranty and performance-related specifications, which, if
developed and implemented, could lead to the improved performance of preventive
maintenance treatments. The current priority for this research topic is low. In part, this is
because more agencies are still trying to determine what treatments to apply and what
type of performance could be expected from those treatments. It is difficult to develop
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warranties or performance-related specifications when the expected performance of a
treatment under different conditions is not well known.
Policy
Throughout the survey responses there are also a number of issues raised that relate to
agency policy:
Funding: issues include creating funding, getting dedicated funding, justifying funding to
maintain conditions.
SHA organizational issues, including program champions, management and
Region/District buy-in, centralized versus decentralized programs, pressure from planners
and others.
External pressures: politics, pressure from other industries, public perception.
These do not necessarily correspond to research needs, but the frequency with which these issues
are identified by respondents suggests that they need to be addressed for pavement preservation
to be successful. No published research was identified on these topics; at the same time, research
is not necessarily the best way to address these policy issues. As these are issues that are faced
by all agencies implementing pavement preservation programs, a good approach to addressing
these issues is through information sharing.
Training
Training on pavement preservation has long been recognized as a need, such as at the Caltrans
workshop (83) and in the 2003 PPETG survey. Identified training topics include the following:
Design and construction of quality preventive maintenance treatments.
Training and certification of technicians.
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Presenting results to facilitate implementation.
One training-related topic was presented in Question 3 (the second bullet above) and respondents
rated it the lowest priority of all of the selections (i.e., 21st out of 21 topics). Further input on
agency training needs is found in the answers to Questions 30, 31, 32, and 33 in the survey, as
they collectively address training on pavement preservation and preventive maintenance.
Since the late 1990s, the NHI has sponsored the development of four training courses under the
general heading of pavement preservation:
Pavement Preservation: The Preventive Maintenance Concept (NHI Course 131054).
Pavement Preservation: Selecting Pavements for Preventive Maintenance Treatments
(NHI Course 131058).
Pavement Preservation: Design and Construction of Quality Preventive Maintenance
Treatments (NHI Course 131103).
Pavement Preservation: Integrating Pavement Preservation Practices and Pavement
Management (NHI Course 131104).
The first two courses have been presented to SHAs over 80 times since 2000, while the last two
were just completed in 2004. Question 30 asks respondents to identify their familiarity with these
courses. Of 34 responses to this Question, 22 either have conducted at least one of the courses or
have plans to conduct a course, 8 are aware of the courses but have no plans to hold one, and 4 are
unaware but interested. Perhaps more importantly, Question 31 asks if the agency has trained its
staff on preventive maintenance topics, and 27 of 31 respondents responded positively, indicating
that between NHI courses and in-house training most agencies are providing training on topics of
interest. Question 32 specifically addresses technician certification, asking if the agency’s technician
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certification program includes preventive maintenance. Here only 3 of 31 respondents said yes;
those that responded positively are focusing their attention either on the materials or on HMA
surfaces.
Question 33 asks about training needs that are not currently being met. Six of the 19 responding
agencies replied “none,” and the others identify a range of topics. The most commonly cited topic is
construction inspection training, treatment design, and treatment placement.
As with the policy issues discussed above, while training of personnel is crucial both to
establishing and improving a pavement preservation program, these training needs do not
necessarily constitute “research” needs. It is recommended that agencies continue to educate
their personnel on all aspects of pavement preservation, from general concepts to detailed
treatment design, construction, and QA/QC procedures. In addition, to enhance the education
process, agencies should take advantage of all available experience and resources (e.g., NHI
training courses, NCPP, FP2, and so on). The need for the development of additional training
resources should be revisited in several years.
SUMMARY
This chapter identifies and discusses gaps between identified pavement preservation research
needs and past or ongoing research on the same topics. The outcome is an updated list of
research needs and topics of interest, organized into the following general categories:
Information sharing.
Materials selection and mix design.
Selection of treatments and treatment strategies.
Construction
Treatment/pavement performance.
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Specifications.
Policy.
Training.
Within each of these categories, specific interests and research topics were identified and
assigned subjective priority ratings of high, medium, and low, based on a combined assessment
of the following:
Previously defined research topics and problem statements produced by many expert-
based group meetings and workshops.
Assessment of past relevant research gleaned from the literature search conducted under
this study.
Research interests and needs identified by agency respondents to the 2004 pavement
preservation survey.
SUGGESTIONS FOR ADDITIONAL RESEARCH
The following sections summarize the recommended pavement preservation research topics.
Additional comments offer a concise explanation of the topic. Note that within each category,
the topics are not listed in a ranked order.
High Priority Research Topics
These are topics in which it is believed that there is a very high level of interest and the
greatest need. Successfully completed research on these topics is likely to provide the greatest
overall benefits.
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Economic evaluation of treatment effectiveness. Documentation of the effectiveness of
pavement preservation, or the further development and refinement of tools to evaluate
effectiveness, would help to overcome implementation obstacles such as obtaining
program funding, demonstrating the benefits of the programs to upper management, and
convincing the public to accept treating roads in good condition.
Development/enhancement of treatment selection guidelines. Research should focus on
the advantages and disadvantages of different treatment selection methods as well as
methods for the development of such guidelines.
Integration of preventive maintenance and pavement management. The potential impact
of improvements in this area and the wide differences in individual agency approaches
make this a short-term research need.
Development of improved treatment timing guidelines. Improved guidance on
preservation treatment timing would address issues such as shifting away from worst-first
treatment selection, showing early benefits of pavement preservation, and overcoming
treatment failures. As there is a recently completed study on this topic, it is suggested
that research focus on implementing the research findings.
Tools to measure preventive maintenance treatment/pavement performance. More
research is needed on the measurements of performance that reflect the benefits of
pavement preservation.
Construction and monitoring of treatment test sections. Test sections are recommended
to evaluate treatment performance and the effect of treatment performance on pavement
performance. While this is an area that may be best addressed by individual agencies, it
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is believed that a nationally coordinated effort (e.g., through the F-SHRP program) could
be used to address shared concerns and interests across agencies and regions.
Treatment impact on pavement performance (e.g., extension of pavement service life).
The impact of preventive maintenance activities on pavement performance and expected
pavement life should be further explored to develop reasonable expectations and
improved pavement performance models.
Medium Priority Research Topics
These are topics in which there is significant interest, but there has also been a fair amount of
already completed research. There is a recognized benefit to completing research on these
topics, but not necessarily as high a payoff as from the high priority research topics.
Development of best practices manuals associated with preventive maintenance
treatments. For consistency purposes, agencies should develop best practices manuals for
the treatments included in their pavement preservation program. However, agencies
should review similar, existing publications as a start to that process.
Improving mix design methods for thin surface treatments for bituminous-surfaced
pavements. This topic is continuing to gain interest as agencies gain experience with
different surface treatments. However, it is not yet recognized as a short-term need by
most agencies.
Treatment impact on noise, friction, and smoothness. The immediate and long-term
effects of various treatments on functional performance is not well documented.
Research would help to identify treatment benefits and also address issues of treatment
timing.
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Performance measurements/criteria for preservation treatments. More research is needed
to identify appropriate measures and criteria for measuring the performance of pavement
preservation treatments.
Low Priority Research Topics
These topics have in common the fact that they were not rated very highly by survey
respondents. Underlying this is the perception that there are other more important research
topics, and that conducting research on these topics is premature. At the same time, it is likely
that some agencies are at the point in the development or implementation of their pavement
preservation programs that they would benefit more from researching these topics.
Investigation of construction factors that affect treatment performance. A research effort
on this topic is considered premature. Agencies first need to better understand what
treatments to apply and when to apply them.
Development and implementation of innovative treatment construction techniques and
equipment. Many agencies still find the application of preventive maintenance
treatments to be innovative; therefore, agencies should first gain more experience with
existing treatments before focusing on construction innovation.
Documentation of the effectiveness of crack and joint sealant materials. Agency needs in
this research area are decreasing. However, as the performance of sealant materials is
specific to local climate conditions and preparation techniques, it is anticipated that
independent agency studies will continue to explore this topic.
Documentation of best practices for use of PCC materials in preventive maintenance
treatments on PCC pavements. There appears to be very little current interest in this
research topic.
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Guidance on improved specifications for preventive maintenance treatments. In general,
more research on this topic is considered premature as many agencies are still trying to
determine what treatments to apply and what type of performance could be expected
from those treatments.
In addition to the above, there are three general topics of interest—Information Sharing,
Policy, and Training—for which there are no actual, defined research needs, but which still
require support and initiatives. Since many agencies are currently in the early stages of
implementing their pavement preservation programs, the priority for support for all three of these
categories is labeled as high.
Information sharing. In order to get the most benefit out of any pavement preservation
initiatives, agencies should make an effort to learn from the experiences (both good and
bad) of other agencies. Current initiatives in establishing regional pavement preservation
centers are a good first step and should be encouraged.
Policy. Policy issues that appear common to many agencies include the following:
- Funding: Creating funding, securing dedicated funding, and justifying funding
needs to maintain conditions.
- SHA organizational issues: developing program champions, obtaining
management and Region/District buy-in, sustaining both centralized and
decentralized programs, resisting internal pressures against preservation.
- External pressures: Politics, pressure from other industries, public perception.
Training. Educating agency personnel on all aspects of pavement preservation is crucial
to the success of a pavement preservation program. It is recommended that agencies take
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advantage of all available national knowledge and resources (e.g., NHI training courses,
NCPP, FP2, and so on) to improve their educational process.
RECOMMENDATIONS
The SHA responses to this project’s comprehensive survey of pavement preservation
practices and the results of a review of ongoing and completed research support the contention
that there is a strong need for pavement preservation research. Accordingly, a series of potential
pavement preservation research topics is identified and organized into priority levels of low,
medium, and high based on the needs expressed by SHAs and the availability of existing
resources to help to meet those needs. However, the identified research topics are not research
statements, and it is research statements that are needed in order to generate funding at the state
and national level, identify researchers, and complete the research.
The next step is to generate research problem statements. The research needs with the
highest priority are those that are identified as having the greatest potential payoff, and it is from
that list that the first projects should be developed. At the national level, problem statements
should be developed with input from individuals with backgrounds at the federal, state, and local
level, and representation from industry and academia. This provides the greatest assurance that
the research will meet existing needs without replicating existing initiatives. At the local level,
research should be undertaken to address the issues that are unique to the agency. However,
coordination and communication among agencies can again help to ensure that duplication is
minimized and that interested agencies have the greatest opportunity to learn from others’
experiences.
REFERENCES
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29. Davis, L., “Protecting Roads in the Desert: Chip Sealing Over Fabric Retards Reflective Surface Cracks.” TR News 228, September-October 2003, Transportation Research Board, Washington, DC (2003) pp 14-15.
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31. Eltahan, A. A., J. F. Daleiden, and A. L. Simpson, “Effectiveness of Maintenance Treatments of Flexible Pavements.” Transportation Research Record 1680, Transportation Research Board, Washington, DC (1999) pp 18-25.
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33. Chen, D. H., D. F. Lin, and H. L. Luo, “Effectiveness of Preventive Maintenance Treatments Using Fourteen SPS-3 Sites in Texas.” Journal of Performance of Constructed Facilities, Volume 17, No. 3, American Society of Civil Engineering, Reston, VA (2003) pp. 136-143.
34. Hildebrand G. and S. Dmytrow, “Looking at Long-Term Results: Performance of Test Section After 13 Years.” TR News 228 September-October 2003, Transportation Research Board, Washington, DC (2003) pp 12-13.
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35. Smith, K. L. and A. R. Romine, “LTPP Pavement Maintenance Materials: SHRP Crack Treatment Experiment.” Report No. FHWA-RD-99-143, Federal Highway Administration, Washington, DC (1999) 163 pp.
36. Smith, K. L. and A. R. Romine, “Materials and Procedures for Sealing and Filling Cracks in Asphalt-Surfaced Pavements.” Report No. FHWA-RD-99-147, Federal Highway Administration, Washington, DC (2001) 108 pp.
37. Ponniah, J. E. and G. J. Kennepohl, “Crack Sealing In Flexible Pavements: A Life-Cycle Cost Analysis.” Transportation Research Record 1529, Transportation Research Board, Washington, DC (1996) pp 86-94.
38. Hand, A. J., K. A. Galal, D. R. Ward, and C. Fang, “Cost-Effectiveness of Joint and Crack Sealing: Synthesis of Practice.” Journal of Transportation Engineering, Volume 126, No. 6, American Society of Civil Engineering, Reston, VA (2000) pp 521-529.
39. Eacker, M. J. and A. R. Bennett, “Bituminous Crack Filling Test Section on US-10 Near Evart.” Research Report No. R-1356, Michigan Department of Transportation, Lansing, MI (1998) 21 pp.
40. B. T. Bellner & Associates (Bellner), “Effectiveness of the Capital Preventive Maintenance Program.” Report prepared for MDOT, Michigan Department of Transportation, Lansing, MI (2001).
41. CTC & Associates LLC (CTC), “Pavement Preventive Maintenance.” Transportation Synthesis Report prepared for the Bureau of Highway Operations, Division of Transportation Infrastructure Development, Wisconsin Department of Transportation, Madison, WI (2003) 8 pp.
42. Outcalt, W., “SHRP Chip Seal.” Report No. CDOT-DTD-R-2001-20, Colorado Department of Transportation, Denver, CO (2001) 12 pp.
43. Labi, S. and K. C. Sinha, “Effectiveness of Highway Pavement Seal Coating Treatments.” Journal of Transportation Engineering, January/February 2004, American Society of Civil Engineers, Reston, VA (2004) pp 14-23.
44. Young, F., A. Robinson, and B. Rowley, “Seal Coats in Manitoba.” Transportation Research Record 1096, Transportation Research Board, Washington, DC (1986) pp 135-139.
45. Rajagopal, A. S. and K. P. George, “Pavement Maintenance Effectiveness.” Transportation Research Record 1276, Transportation Research Board, Washington, DC (1990) pp 62-68.
46. Mouaket, I.M., K.C. Sinha, and T.D. White, “Guidelines for Management of Chip and Sand Seals Coating Activities in Indiana.” Transportation Research Record 1344, Transportation Research Board, Washington, DC (1992) pp 81-90.
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47. Al-Mansour, A. I. and K. C. Sinha, “Economic Analysis of Effectiveness of Pavement Preventive Maintenance.” Transportation Research Record 1442, Transportation Research Board, Washington, DC (1994) pp 31-37.
48. Smith, R., T. Freeman, and O. Pendleton, "Pavement Maintenance Effectiveness," Report No. SHRP-H-358, Strategic Highway Research Program, National Research Council, Washington, DC, (1993) 350 pp.
49. Syed, I. M, T. J., Freeman, and R. E. Smith, “Effectiveness of Highway Maintenance Treatments Used in Texas.” Flexible Pavement Design and Maintenance ASTM STP 1348, P.S. Kandhal and M. Stroup-Gardner, Editors, American Society for Testing and Materials, Philadelphia, PA (1998).
50. Wade, M., R. DeSombre, and D. Peshkin, “High Volume/High Speed Asphalt Roadway Preventive Maintenance Surface Treatments.” Report No. SD99-09, South Dakota Department of Transportation, Office of Research, Pierre, SD (2001) 151 pp.
51. Center for Transportation Research and Education (CTRE), “Thin Maintenance Surfaces: Phase Two Report with Guidelines for Winter Maintenance on Thin Maintenance Surfaces.” Project TR-435, Center for Transportation Research and Education, Iowa State University, Ames, IA (2003) 131 pp.
52. Nazarian, S., “Impact of Sealers/Rejuvenators on Short-Term Modulus of Asphalt Concrete Layers.” Draft Report, Foundation for Pavement Preservation, McLean, VA (2002) 28 pp.
53. Dunn, C. and B. Fuchs, “Modified Chip Seal Surface Treatments Vs. Conventional Chip Seal Surface Treatments.” Report No. ND 96-03, North Dakota Department of Transportation, Materials and Research Division, Bismark, ND (2002) 93 pp.
54. Hanson, D. I., “Construction and Performance of an Ultrathin Bonded Hot-Mix Asphalt Wearing Course.” Transportation Research Record 1749, Transportation Research Board, Washington, DC (2001) pp 53-59.
55. Uhlmeyer, J. S., L. M., Pierce, and J. T. Weston, “NovaChip®.” Post Construction/Performance Report, Experimental Feature WA01-01, Washington State Department of Transportation, Olympia, WA (2003) 48 pp.
56. Rajagopal, A., I. Minkarah, R. Green, and A. Morse, “Design of an Experiment to Evaluate Effectiveness of Crack Sealing on Pavement Serviceability and Life.” CD-ROM for the 83rd Annual Meeting, Transportation Research Board, Washington, DC (2003) 33 pp.
57. Marquart, M., “Evaluation of CRAFCO Crack Sealant On Asphalt Pavement.” Report No. ND 96-04, North Dakota Department of Transportation, Materials and Research Division, Bismark, ND (2001) 42 pp.
58. Center for Transportation Research and Education (CTRE), “Thin Maintenance Surfaces: Phase One Report.” CTRE Management Project 97-14, Center for Transportation Research and Education, Iowa State University, Ames, IA (1999) 57 pp.
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59. Evert, K., “Microsurfacing Performance Evaluation.” Construction Report NH-5-085(041)041, North Dakota Department of Transportation, Materials and Research Division, Bismark, ND (2003) 40 pp.
60. Evans, L. D., A. R. Romine, A. J. Patel, and A. G. Mojab, “Concrete Pavement Repair Manuals of Practice.” SHRP-H-349, Strategic Highway Research Program, National Research Council, Washington, DC (1993) 139 pp.
61. Evans, L. D., K. L. Smith, and A. R. Romine, “Materials and Procedures for the Repair of Joint Seals in Portland Cement Concrete Pavements—Manual of Practice.” FHWA-RD-99-146, Federal Highway Administration, McLean, VA (2001) 127 pp.
62. Smith, K. L., M. A. Pozsgay, L. D. Evans, and A. R. Romine, “LTPP Pavement Maintenance Materials: SPS-4 Supplemental Joint Seal Experiment, Final Report.” FHWA-RD-99-151, Federal Highway Administration, McLean, VA (1999) 164 pp.
63. Olson, R. and R. Roberson, “Edge-Joint Sealing as a Preventive Maintenance Practice.” Report No. MN/RC 2003-26, Minnesota Department of Transportation, Office of Materials and Road Research, Maplewood, MN (2003) 19 pp.
64. Shober, S. F., “The Great Unsealing—A Perspective on Portland Cement Concrete Joint Sealing.” Transportation Research Record 1597, Transportation Research Board, Washington, DC (1997) 31 pp.
65. Rutkowski, T. S., S. F. Shober, and R. B. Schmeidlin, “Performance Evaluation of Drained Pavement Structures.” Report No. WI/SPR-04-08, Wisconsin Department of Transportation, Madison, WI (1998) 44 pp.
66. Morian, D. A. and S. Stoffels, “Joint Seal Practices in the United States—Observation and Consideration.” Transportation Research Record 1627, Transportation Research Board, Washington, DC (1998) pp 7-12.
67. Roberts, J. H. and J. W. Mack, “Dowel Bar Retrofit in Portland Cement Concrete Pavement.” National Pavement Preservation Forum II: Investing In the Future CD-ROM, Publication No. FHWA-IF-03-019, Federal Highway Administration, Washington, DC (2001) 12 pp.
68. Pierce, L. M, J. Uhlmeyer, J. Weston, J. Lovejoy, and J. P. Mahoney, “Ten-Year Performance of Dowel-Bar Retrofit: Application, Performance, and Lessons Learned.” Transportation Research Record 1853, Transportation Research Board, Washington, DC (2003) pp 83-91.
69. Mahoney, J. P., M. D. Pietz, and K. W. Anderson, “Summary Report on the State of Pavement Technology Consortium.” Report No. WA-RD 487.1, Washington State Department of Transportation, Olympia, WA (2000) 54 pp.
70. Bischoff, D. and A. Toepel, “Dowel Bar Retrofit: STH 13 Construction & One-Year Performance Report.” Report No. WI-07-02, Wisconsin Department of Transportation, Madison, WI (2002) 44 pp.
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71. Michigan Department of Transportation (MDOT), “Restoring Portland Cement Concrete: MDOT Investigates Dowel Bar Retrofit Procedure for Improving and Preserving Load Transfer at Cracks.” Construction and Technology (C&T) Research Record, Issue Number 91, October 2000, Michigan Department of Transportation, Construction and Technology Division, Lansing, MI (2000).
72. International Grooving & Grinding Association/American Concrete Paving Association (IGGA/ACPA), “Diamond Grinding and Concrete Pavement Restoration.” TB-008.01P, International Grooving and Grinding Association, Skyland, NC; American Concrete Paving Association, Skokie, IL (2000) 28 pp.
73. Rao, S., H. T. Yu, and M. I. Darter, “The Longevity and Performance of Diamond-Ground Concrete Pavements,” PCA R&D Serial No 2175, Portland Cement Association, Skokie, IL (1999) 112 pp.
74. Snyder, M. B., M. J. Reiter, K. T. Hall, and M. I. Darter, “Rehabilitation of Concrete Pavements; Volume I—Repair Rehabilitation Techniques.” Report No. FHWA-RD-88-071, Federal Highway Administration, Washington, DC (1989) 249 pp.
75. Amos, D., “Evaluation of Diamond Grinding New PCCP: Route 60, Butler County.” Report No. RDT00-005, Missouri Department of Transportation, Research Development and Technology Division, Jefferson City, MO (2000) 35 pp.
76. Donahue, J., S. Johnson, and E. Burks, “Evaluation of Undersealing and Diamond Grinding Rehabilitation.” Report No. RDT 00-009, Missouri Department of Transportation, Research Development and Technology Division, Jefferson City, MO (2000) 52 pp.
77. Barron, B. J., “In-Situ Repair of Base and Sub-Base Materials Using High Density Polyurethane for AC and PCC Pavements Extending the Life of Your Pavements.” National Pavement Preservation Forum II: Investing In the Future CD-ROM, Publication No. FHWA-IF-03-019, Federal Highway Administration, Washington, DC (2001) 6 pp.
78. Blankenship, P. and D. R. Leach, “Performance-Related Specifications for Pavement Preservation Techniques.” National Pavement Preservation Forum II: Investing In the Future CD-ROM, Publication No. FHWA-IF-03-019, Federal Highway Administration, Washington, DC (2001) 16 pp.
79. Galehouse, L., “Innovative Concepts for Preventive Maintenance.” Transportation Research Record 1627, Transportation Research Board, Washington, DC (1998) pp 1-6.
80. Brown, L., “Caltrans Warranty Pilot—Ensure Pavement Preservation.” National Pavement Preservation Forum II: Investing In the Future CD-ROM, Publication No. FHWA-IF-03-019, Federal Highway Administration, Washington, DC (2001) 7 pp.
81. Transportation Research Board (TRB). “Maintenance Research Master Planning Workshop.” Transportation Research E-Circular Number E-C022, Transportation Research Board, Washington, DC (2000) 76 pp.
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82. Foundation for Pavement Preservation (FP2), “Pavement Preventive Maintenance Guidelines.” Foundation for Pavement Preservation, Austin, TX (2001) 25 pp.
83. Moulthrop, J. S., R. G. Hicks, and J. A. Epps, “Pavement Preservation Research Problem Statements.” Publication No. FHWA-IF-02-017, Federal Highway Administration, Washington, DC (2001) 72 pp.
84. Transportation Research Board (TRB), “Strategic Highway Research: Saving Lives, Reducing Congestion, Improving Quality of Life.” Special Report 260, Transportation Research Board, Washington, DC (2001) 218 pp.
85. Pope, L., “Infrastructure Research and Technology Stakeholder Workshop Summary Report: Workshop Proceedings (October 31-November 1, 2002, Chicago, Illinois).” Report No. FHWA-RD-03-071, Federal Highway Administration, McLean, Virginia (2003) 94 pp.
86. Transportation Research Board (TRB), TR News 228, September-October 2003 Issue, Transportation Research Board, Washington, DC (2003) 56 pp.
87. Wilson, T. P., Smith, K. L. and A. R. Romine, “LTPP Pavement Maintenance Materials: PCC Partial-Depth Spall Repair Experiment, Final Report.” Report No. FHWA-RD-99-153, Federal Highway Administration, Washington, DC (1999) 115 pp.
88. Wilson, T. P., Smith, K. L. and A. R. Romine, “Materials and Procedures for Rapid Repair of Partial-Depth Spalls in Concrete Pavements—Manual of Practice.” Report No. FHWA-RD-99-142, Federal Highway Administration, Washington, DC (2001) 135 pp.
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APPENDIX B. SUMMARY OF PAVEMENT PRESERVATION SURVEY QUESTIONNAIRE RESPONSES
INTRODUCTION
In 2004, a questionnaire was distributed to all 50 United States and four Canadian provinces
to learn more about the current state of the practice in pavement preservation. Specifically, the
questionnaire focused on identifying pavement-preservation related research being conducted by
these individual agencies, as well as identifying their immediate preservation-related research
needs. In an effort to lesson the time required to fill out the sixteen page questionnaire, the
questionnaire was developed as a macro-driven Microsoft® Word document. Specifically, many
of the modern day software controls (e.g., check boxes, drop down list boxes, etc.) were included
in the interface of the electronic questionnaire to expedite the completion process. The following
35 agencies responded to the survey:
Alaska Nebraska Arizona Nevada Arkansas New Jersey British Columbia New Mexico California New York Colorado North Carolina Florida North Dakota Idaho Ohio Illinois Oklahoma Indiana Ontario Kansas Oregon Maryland Rhode Island Massachusetts Texas Michigan Vermont Minnesota Virginia Mississippi Washington Missouri Wisconsin Montana
B-1
B-2
In this appendix, the survey results from these 35 agencies are summarized to provide a
snapshot of the current state of the practice in pavement preservation. Although definitions of
pavement preservation and preventive maintenance were provided as part of the survey, the
received survey responses make it obvious that different agencies continue to define preventive
maintenance differently. For example, a number of agencies stated that they were applying
preventive maintenance on pavements in poor and very poor condition. Although the treatments
used on these pavements in poor condition may be considered approved preventive maintenance
treatments, they are by definition, not preventive in nature unless applied to pavements in good
or very good condition. So, as with most surveys, there is undoubtedly some variability
inherently included in the summarized responses due to the differences in understanding of what
each question is asking.
While caution should be used when interpreting the details of the collected responses, due to
the number of responses it is believed that the observed trends in the summarized data are valid.
Therefore, in this appendix, the results of each question are looked at independently. In addition
to presenting the actual agency responses and comments, where appropriate a trend in the
responses is interpreted.
QUESTIONNAIRE RESPONDENT INFORMATION
Table B-1 provides contact information for the 35 questionnaire respondents. However, in
many cases the responses were put together by more than one agency representative.
Table B-1. Questionnaire primary respondent information.
Name Title State Phone Number E-mail
R. Scott Gartin, P.E. Statewide Pavement Engineer AK (907) 269-6244 [email protected]
Mark A. Evans, P.E. Pavement Management Engineer AR (501) 569-2234 [email protected]
Jim Delton, Yongqi Li, Larry Scofield
Arizona DOT AZ (602) 712-7286 [email protected]
Mike Oliver Chief, Geotechnical, Materials and Pavement Engineer
BC (250) 387-3353 [email protected]
Rob Marsh Pavement Management Engineer- Central Region
CA (916) 654-5640 [email protected]
Mike Keleman Engineer in Training - 3 CO (303) 757-9298 [email protected]
Gale C. Page State Flexible Pavement Materials Engineer
FL (352) 955-2903 [email protected]
Dave Jones State Maintenance Engineer ID (208) 332-7893 [email protected]
LaDonna Rowden Pavement Technology Engineer IL (217) 782-8582 [email protected]
Todd Shields Field Engineer IN (317) 232-5506 [email protected]
Dean M. Testa Chief Bureau of Construction & Maintenance
KS (785) 296-3576 [email protected]
Matthew Turo Pavement Management Engineer MA (617) 973-7266 [email protected]
Peter Stephanos Director of Materials and Technology MD (410) 321-3100 [email protected]
Kevin Kennedy Capital Preventive Maintenance Engineer
MI (517) 322-6043 [email protected]
Jerry Geib Pavement Preventive Maintenance Engineer
MN (651) 779.5937 [email protected]
B-3
Name Title State Phone Number E-mail
Tom Borgmeyer Senior Tech Support Engr.-Maint. MO (573) 751-1157 [email protected]
Mark McConnell Asst. State Maintenance Engineer MS (601) 359-7111 [email protected]
Jon S. Watson, P.E. Pavement Engineer MT (406) 444-7260 [email protected]
Emily O. McGraw, P.E. Pavement Preservation Engineer NC (919) 733-3725 [email protected]
NDDOT Maintenance and Engineering Services Division
ND (701) 328-2545 Not included
Laird E. Weishahn Flexible Pavement Engineer NE (402) 479-4675 [email protected]
Andris A. Jumikis Supervising Engineer NJ (609) 530-3036 [email protected]
Robert S. Young Pavement Management Engineer NM (505) 827-0051 [email protected]
Frank G. Taylor Chief Maintenance Engineer NV (775) 888-7054 [email protected]
Edward J. Denehy Pavement Program Engineer NY (518) 457-6914 [email protected]
Roger Green/Aric Morse Pavement Research Engineer/ Pavement Design Coordinator
OH (614) 995-5993 / (614) 995-5994
[email protected] / [email protected]
Ginger McGovern, PE Pavement Management Engineer OK (405) 522-1447 [email protected]
Tom Kazmierowski Manager of Pavements & Foundations Section
ON (416) 235-3512 [email protected]
John Coplantz Pavement Management Engineer OR (503) 986-3119 [email protected]
Colin Franco Managing Engineer RI (401) 222-3030 [email protected]
Joe S. Graff, P. E. Deputy Director, Maintenance Division TX (512) 416-3195 [email protected]
Douglas C. Gilman, P.E. State Pavement Management Engineer VA (804) 786-7646 [email protected]
Mike Hedges Paving Program Manager VT (802) 828-2793 [email protected]
Linda M. Pierce, PE State Pavement Engineer WA (360) 709-5470 [email protected]
Table B-1. Questionnaire primary respondent information (continued).
B-4
1.0 PAVEMENT PRESERVATION-RELATED RESEARCH
Survey Question 1
How would you describe your agency’s familiarity with the pavement preservation and preventive maintenance research being conducted by other agencies? (Check the one answer that is most representative).
Table B-2 presents the 35 agency responses and includes summary statistics associated with
the answers. Individual agency comments associated with this question are also included below.
Table B-2. Summary of agency familiarity with pavement preservation and preventive maintenance research being conducted by other agencies (Question 1).
Very Familiar Somewhat Familiar Minimal
Knowledge No Knowledge 9 of 35 (26 %) 17 of 35 (48 %) 9 of 35 (26 %) 0 of 35 (0 %)
Agency Comments:
The Department is constantly evaluating new treatment alternatives and monitoring new pavement surface treatment research.
[Our agency] has been involved with the FHWA and Foundation for Pavement Preservation since its inception and has been a lead state in preventive maintenance funding as a part of roadway maintenance.
The distresses occurring on flexible pavements in [our state] have not been of a severity and extent to result in an aggressive pavement preservation program. This may be due to [our agency’s] climate and materials used in flexible pavement construction.
We occasionally get TRB, NCHRP, and neighboring state DOT research publications sent our way.
We have a little knowledge [of] what other states may be doing preventative maintenance research.
It is difficult to find information about research in progress. The internet has made it much easier to find completed research. Our DOT library will do searches on topics we request.
We have read national reports and even fewer state reports. It is difficult knowing what is going on in other states.
Our Research Section is less than 5 years in existence and very active in our local research interests. As time passes, they're beginning to have contacts that help us become familiar with what others are doing.
Familiar with national studies, not very familiar with studies done by individual states.
B-5
Have not had time to become intimate with what other states are doing on preventive maintenance. What we call preservation, you would probably call rehabilitation.
Recently served on NCHRP synthesis study on chips seals. To be published soon.
[Our agency] has actively pursued staying aware of research being conducted by other SHA's.
Familiar with the states of Florida, Minnesota, California, and Texas through the State Pavement Technology Consortium. But only familiar with other states through meetings, conferences, etc.
Survey Question 2
Would knowing about ongoing pavement preservation-related research in other agencies influence the research undertaken by your agency? (Check the one answer that is most representative).
Table B-3 presents the 35 agency responses and includes summary statistics associated with
the answers. Individual agency comments associated with this question are also included below.
Table B-3. Summary of whether or not agency research decisions would be influenced by ongoing research in other agencies (Question 2).
Yes No 31 of 35 (90 %) 4 of 35 (10 %)
Agency Comments:
I do not believe having more "shelf documents" is the answer. The proof is out there, but the political will is against us.
It could save us from duplicating what other states are doing.
Some localized studies to verify findings by others could results in relatively low-cost improvements.
Every location is different in materials, climate, soil type, aggregate type, and etc. Depending on how the "research fits" our needs it could influence what we do.
Our agency does not routinely conduct formal research in pavement preservation. We rely on national studies, ad hoc informal agency studies, etc.
A TRIS and research in progress search is conducted prior to the start of any research.
If other states have good results, we might be able to get similar studies for [our agency’s] roads.
By knowing other SHA activities, the development of problem statements is formulated such that they augment ongoing national level research.
B-6
B-7
Absolutely, the pavement research budget for [our agency] has been approximately $200K per biennium. Therefore, we are more than willing to review, evaluate, and implement research by others.
Survey Question 3
Please use the following matrix to describe the details of your past, current, and future research activities and interests (check all that apply). If you indicate that you have interest in a particular topic, please indicate the degree of this interest by assigning an interest ranking (on a 1 to 10 scale) in the last column of the table. Note that the Interest Rankings are initially set equal to “n/a” = not applicable. On the next page, please include any corresponding details that better explain your ongoing research activities or interests.
Because this question assesses the past research activities and current research interests in over
twenty different research topics, the resulting matrix of results is somewhat complex. The actual
agency-by-agency responses to each included research topic are summarized in table B-4. It is,
however, important to remember that not all agencies provided a response for each included
research topic, and many did not provide quantitative information that identifies their level of
interest in a topic (i.e., “interest rankings”). Individual agency comments associated with this
question are included below (note that most of the comments make reference to the numerical
topic ID noted in the table). A more detailed summary of the collective results to this question is
included in the Interpretation of Results section below.
Agency Comments (note that some of these responses reference a specific “Topic ID” shown in table B-4):
(#18) Superpave and SMA mixes with various specifications and High Float Surface Treatments.
(#18) [Our agency] has a new products committee that evaluates various products and techniques new to the market. This committee provides input to District personnel regarding these products and techniques. The Districts have the flexibility to employ different rehabilitation strategies at the discretion of the District Engineer. These treatments are monitored for their performance. (#24) [Our agency] is in the process of establishing a lightweight profiler operator and equipment certification program for Department and Contractor personnel and equipment.
Table B-4. Summary of past, current, and future research activities and interests (Question 3). T
opic
ID
Research Area/Topic Conducted Past
Research Conducting
Ongoing Research Plans for Future
Research Interest in Research by Other Agencies
Interest Ranking (10 = high interest, 0 = no interest)
SPECIFICATIONS
1. Treatment QC/QA specifications 9 of 35 (26%) 8 of 35 (23%) 4 of 35 (11%) 25 of 35 (71%) Avg. Ranking = 6.5 (26 respondents)
2. Treatment performance-related specifications (PRS)
2 of 35 (6%) 6 of 35 (17%) 4 of 35 (11%) 24 of 35 (69%) Avg. Ranking = 5.9 (27 respondents)
3. Warranties for treatments 5 of 35 (14%) 11 of 35 (31%) 5 of 35 (14%) 26 of 35 (74%) Avg. Ranking = 6.1 (27 respondents)
4. Other(s): Composite pay factors for HMA or
concrete. End result specification(s). How (do) ranges in specifications impact
performance?
1 of 35 (3%)
1 of 35 (3%)
1 of 35 (3%)
1 of 35 (3%)
9: Individual Agency Ranking 6: Individual Agency Ranking 7: Individual Agency Ranking
MATERIALS SELECTION/MIX DESIGN
5. Binder and aggregate tests and procedures 11 of 35 (31%) 12 of 35 (34%) 4 of 35 (11%) 21 of 35 (60%) Avg. Ranking = 5.8 (26 respondents)
6. Crack and joint sealant material studies 16 of 35 (46%) 9 of 35 (26%) 7 of 35 (20%) 24 of 35 (69%) Avg. Ranking = 6.0 (28 respondents)
7. In situ pavement property investigations to improve mix/treatment design
13 of 35 (37%) 8 of 35 (23%) 5 of 35 (14%) 24 of 35 (69%) Avg. Ranking = 6.2 (28 respondents)
8. Other(s): Aggregate polish value testing policies. Materials characterization in support of
200X (design guide).
1 of 35 (3%)
1 of 35 (3%)
1 of 35 (3%)
8: Individual Agency Ranking 9: Individual Agency Ranking
TREATMENTS AND STRATEGY SELECTION 9. Characteristics of candidate pavements for
preventive maintenance 4 of 35 (11%) 14 of 35 (40%) 6 of 35 (17%) 24 of 35 (69%) Avg. Ranking = 7.4 (27 respondents)
10. Development/enhancement of treatment selection guidelines
9 of 35 (26%) 10 of 35 (29%) 7 of 35 (20%) 25 of 35 (71%) Avg. Ranking = 7.6 (28 respondents)
11. Investigation of optimal treatment timing 5 of 35 (14%) 8 of 35 (23%) 7 of 35 (20%) 27 of 35 (77%) Avg. Ranking = 7.6 (28 respondents)
12. Economic evaluation of treatment effectiveness
6 of 35 (17%) 7 of 35 (20%) 8 of 35 (23%) 26 of 35 (74%) Avg. Ranking = 7.9 (28 respondents)
13. Other(s): Integration of NCHRP 14-14.
1 of 35 (3%)
5: Individual Agency Ranking
CONSTRUCTION
14. Factors that affect treatment performance (surface preparation, tack coats, weather, and so on)
7 of 35 (20%) 9 of 35 (26%) 4 of 35 (11%) 30 of 35 (86%) Avg. Ranking = 7.0 (27 respondents)
15. Innovative treatment construction techniques/equipment
6 of 35 (17%) 8 of 35 (23%) 6 of 35 (17%) 30 of 35 (86%) Avg. Ranking = 6.9 (28 respondents)
B-8
Top
ic
ID
Research Area/Topic Conducted Past
Research Conducting
Ongoing Research Plans for Future
Research Interest in Research by Other Agencies
Interest Ranking (10 = high interest, 0 = no interest)
CONSTRUCTION (CONTINUED) 16. Innovative field sampling and testing methods
for treatments 5 of 35 (14%) 2 of 35 (6%) 6 of 35 (17%) 27 of 35 (77%) Avg. Ranking = 5.8 (27 respondents)
17. Other(s): Unit costs of innovative treatments. Public Private Transportation Act. Chip Seal Best Practices.
1 of 35 (3%) 1 of 35 (3%)
1 of 35 (3%)
1 of 35 (3%)
1 of 35 (3%)
10: Individual Agency Ranking 10: Individual Agency Ranking 10: Individual Agency Ranking
TREATMENT/PAVEMENT PERFORMANCE
18. Construction and monitoring of treatment test sections. If your agency is currently constructing/monitoring test sections, please indicate specific treatments in the space provided on the next page.
8 of 35 (23%) 19 of 35 (54%) 7 of 35 (20%) 20 of 35 (57%) Avg. Ranking = 7.6 (25 respondents)
19. Analysis of historical data to investigate treatment performance
7 of 35 (20%) 12 of 35 (34%) 11 of 35 (31%) 19 of 35 (54%) Avg. Ranking = 7.4 (25 respondents)
20. Treatment impact on noise, friction, and smoothness
8 of 35 (23%) 12 of 35 (34%) 3 of 35 (9%) 25 of 35 (71%) Avg. Ranking = 6.2 (25 respondents)
21. Treatment impact on pavement performance (e.g., extension of service life)
8 of 35 (23%) 16 of 35 (46%) 7 of 35 (20%) 22 of 35 (63%) Avg. Ranking = 8.1 (25 respondents)
22. Performance measurements/criteria forpreservation treatments
4 of 35 (11%) 10 of 35 (29%) 5 of 35 (14%) 25 of 35 (71%) Avg. Ranking = 7.1 (25 respondents)
23. Other(s): Use of NCHRP 14-14.
1 of 35 (3%)
6: Individual Agency Ranking
OTHERS
24. Training and certification of technicians 4 of 35 (11%) 10 of 35 (29%) 3 of 35 (9%) 18 of 35 (51%) Avg. Ranking = 4.9 (28 respondents) 25. Integration of preventive maintenance and
pavement management 6 of 35 (17%) 12 of 35 (34%) 7 of 35 (20%) 19 of 35 (54%) Avg. Ranking = 7.3 (27 respondents)
26. Standardization of pavement preservation-related definitions
0 of 35 (0%) 6 of 35 (17%) 5 of 35 (14%) 20 of 35 (57%) Avg. Ranking = 5.6 (27 respondents)
27. Other(s): Chip Seal Design Guide-proposed from
AHD20.
1 of 35 (3%)
10: Individual Agency Ranking
Table B-4. Summary of past, current, and future research activities and interests (Question 3) (continued).
B-9
Ongoing research includes surface treatments (e.g. chip seals, slurry seals, etc) and wearing courses (e.g. ARFC, Nova Chip, etc).
We have the odd project with new products, techniques, etc which could be viewed as related research but mainly we rely on research by other agencies.
(#18) [Warranty] (1 year) pilot projects for: chip seals (conventional and RAC binder), slurry seals, microsurfacing, rubberized AC (RAC) thin layer high binder friction course, RAC overlays (thin gap graded, open graded).
[Our agency’s] focus has been on rehabilitation of flexible pavements using "mill and fill" with Hot-Mix Asphalt (HMA). [Our agency] did construct a project in early 1980's to evaluate different surface sealing techniques for cracked pavement to prolong pavement life. The techniques included crack sealing, surface treatment (chip seal), fog seal, slurry seal, and thin lift HMA. The thin lift HMA provided the best performance and was the most cost effective (in fact, the initial cost of all the techniques including the HMA were similar). It should be noted that microsurfacing was not included in this study because it was not an available technique at the time. The final report was shared with the SHRP Maintenance Program, but it has not had much visibility maybe because it was felt that the conclusions were very specific to [Our agency’s] climate and materials.
(#18) [Our agency] will be constructing a series of 27 projects over the next 6 to 9 months using various pavement preservation techniques. These will include seal coats (chip seals), microsurfacing (1-pass and 2-pass), and slurry seals. These projects will be monitored to determine pavement condition improvement and performance of the treatments.
(#18) Profile milling, micro-milling, thin HMA overlay <1.5 in (38 mm), paver-placed surface seals, single course microsurfacing, [combination of] cold milling and HMA [overlay] < 1.5 in (38 mm), [and] ultra-thin HMA overlay[s] <0.75 in (19 mm).
Many of the selections above for past or current research are actually work efforts completed or underway by our office and not necessarily research efforts.
We have an emerging technology program where we are willing to try emerging technologies and we monitor their performance.
(#18) Many projects have left control sections. We need to find these locations and develop a statistical based system to evaluate the performance.
(#18) Monitoring and Chip Seal Projects. 1. Porphyry with polymer modified emulsion. 2. Porphyry with polymer modified asphalt. 3 and 4. Light weight aggregate with polymer modified emulsion.
[Our agency] is currently in the process of developing and implementing a preventive maintenance program. We have hired Larry Galehouse with the National Center for Pavement Preservation to assist us. Ongoing research in other states (especially Southeastern states) is of great interest to us.
After reading the draft report on chip seals, we developed a research needs statement to improve rolling patterns, equipment, and practices.
B-10
Construction methods and materials for concrete paving; construction practices on concrete bridge decks; long term performance of PG Binders; low temperature cracking of PG binders; SHRP test section projects; microsurfacing construction and maintenance operations; saw and seal on asphalt pavement; dowel bar retrofit; high strength concrete bridge decks; and striping paint.
(#18) A proprietary fog seal product (Bio Span) has been applied on a couple locations and will be monitored. (#18) A scrub seal was applied a couple years ago and is being monitored. (#19) Software was developed to use pavement management data to help select proper timing for proper treatments, taking into account treatment performance. (#20) Friction numbers are routinely taken and noise monitoring is just beginning. (#21) Pavement management data is continually being monitored and updated as needed.
(#18) Microsurfacing, slurry seals, Statewide. Cold-in-place recycling, US-6. Asphalt surface treatment test sections, SR-236 (chip, foamed asphalt, cape, CIR, reflex, etc.)
All research indicated in the above answers were informal studies which did not produce formal research reports.
(#18) Currently monitor asphalt surfaced test sections treated with the crack sealing treatment. Plan to monitor test sections treated with microsurfacing and chip seal.
(#18) Research into new technologies underway includes: cold-in-place recycling, cold-in-place recycled expanded asphalt mix, full-depth repair with expanded asphalt stabilization, and pre-cast concrete slab repair.
We don't have much research funds and many competing needs. Since we are mostly doing rehabilitation as opposed to preventive maintenance, we would have to borrow on other state's experience at first.
(#1) Identifying elements to be considered such that treatment effectiveness can be monitored. (#3) [Our agency] is pursuing. (#5 and #7) [Our agency] is studying an in-situ binder rheology. This will support the 200x [design guide] implementation by addressing the issue of lab versus field values. (#9) Both proactive (cyclical) and reactive (condition based) are being considered. (#13, 18, 19, 21, 22, and 23) All relate to NCHRP 14-14 and the Indiana DOT report titled "The Effectiveness of Maintenance and its Impact on Capital Expenditures," FHWA/IN/JTRP-2002/27, SPR-2397. (#19) We are monitoring macro texture surface treatments (RoadArmor) and thin hot-mix asphalt concrete overlays (Nova Chip).
(#18) We are evaluating a Nova Chip, macrosurfacing, and microsurfacing test sections.
While each agency was instructed to check “all that applied,” some agencies did not indicate
an interest ranking, so the computed averages for the interest rankings only consider those
agencies that responded. The statistics included in table B-4 indicate the number of agencies out
of the thirty-five that provided a “yes” answer to a particular research area.
B-11
To gauge which research topics were of most interest to the responding agencies, the interest
rankings were averaged for each provided research topic. These average interest ranking values
were then used to rank the research topics from greatest interest to least interest where the topic
with the greatest interest was assigned a rank of 1. A summary of the average interest rankings
and their prioritized topic rankings is presented in table B-5. The results are not summarized in
table B-5 for Topic ID’s 4, 8, 13, 17, 23, and 27, as those were “Others” fields that allowed
individual agencies to write in related topics not included in the initial questionnaire matrix.
As shown in table B-5, the five research topics with the largest average interest rankings are
the following (note the computed average interest rankings are included in parenthesis):
1. Treatment impact on pavement performance (e.g., extension of service life) (8.1). 2. Economic evaluation of treatment effectiveness (7.9). 3. Development/enhancement of treatment selection guidelines (7.6). 4. Construction and monitoring of treatment test sections (7.6). 5. Investigation of optimal treatment timing (7.6).
A cursory review of the average interest rankings by interest “category” (i.e., Specifications,
Materials Selection/Mix Design, Treatments and Strategy Selection, etc.) finds the most interest
to be in the categories of Treatments and Strategy Selection and Treatment/Pavement
Performance. The least interest appears to be in the categories of Specifications and Materials
Selection/Mix Design.
2.0 PAVEMENT PRESERVATION PROGRAM STATUS
Survey Question 4
Does you agency currently have a pavement preservation program in place? (Check the one answer that is most representative).
Table B-6 presents the 35 responses and includes summary statistics associated with the answers.
Individual agency comments associated with this question are also included below.
B-12
Table B-5. Summary of interest rankings averages and a ranking of Topic IDs based on interest. T
opic
ID
Research Area/Topic
Weighted Average of
Interest Rankings
Prioritized Ranking of Computed Average Interest
Rankings SPECIFICATIONS 1. Treatment QC/QA specifications 6.5 12 2. Treatment performance-related specifications (PRS) 5.9 17 3. Warranties for treatments 6.1 15 MATERIALS SELECTION/MIX DESIGN 4. Binder and aggregate tests and procedures 5.8 18 5. Crack and joint sealant material studies 6.0 16 6. In situ pavement property investigations to improve mix/treatment
design 6.2 13
TREATMENTS AND STRATEGY SELECTION 7. Characteristics of candidate pavements for preventive maintenance 7.4 6 8. Development/enhancement of treatment selection guidelines 7.6 3 9. Investigation of optimal treatment timing 7.6 5 10. Economic evaluation of treatment effectiveness 7.9 2 CONSTRUCTION 11. Factors that affect treatment performance (surface preparation, tack
coats, weather, and so on) 7.0 10
12. Innovative treatment construction techniques/equipment 6.9 11 13. Innovative field sampling and testing methods for treatments 5.8 19 TREATMENT/PAVEMENT PERFORMANCE 14. Construction and monitoring of treatment test sections 7.6 4 15. Analysis of historical data to investigate treatment performance 7.4 7 16. Treatment impact on noise, friction, and smoothness 6.2 14 17. Treatment impact on pavement performance (e.g., extension of service
life) 8.1 1
18. Performance measurements/criteria for preservation treatments 7.1 9 OTHERS 19. Training and certification of technicians 4.9 21 20. Integration of preventive maintenance and pavement management 7.3 8 21. Standardization of pavement preservation-related definitions 5.5 20
B-13
Table B-6. Summary of whether or not agencies currently have a pavement preservation program in place (Question 4).
Yes No 30 of 35 (86 %) 5 of 35 (14 %)
Agency Comments:
We have plans to move towards that. However, our three Regions do fairly independent annual preventive maintenance.
We have a Maintenance Management group in place that determines the effectiveness of the states pavement maintenance system.
Currently have $45 million funding dedicated to preventive maintenance only.
Will be developed over winter 2004/2005.
Is a part of what we call Substantial Maintenance which is our basic funding for Pavement Preservation.
Primarily in the "Pilot Program" phase.
I would describe ours as more of a pavement maintenance program.
Young but growing program.
In the last couple [of years] moneys have been set aside for contracts in pavement preservation applications.
[Our agency currently has a Proactive Pavement Preservation Program (P4)].
[Our agency] has a pavement preventive maintenance program, which is part of our pavement preservation program. The following answers refer to our pavement preventive maintenance program.
Our pavement preservation program was just started in July 2004. It was instituted as a cooperative effort between [our agency] and the local FHWA office to allow federal funding to be used on "lighter" treatments.
Yes, but we include rehabilitation treatments under preservation.
Formal "Preventive Maintenance Program" was developed in 1986 ($115M annually). This program allows for chip seals, level-ups, light overlays ≤ 2 in (50 mm), microsurfacing and any repairs necessary to get the pavement ready for the treatment. It has increased annually to its current level of $250M. In addition, Districts utilize other funding including routine maintenance, Interstate Maintenance and discretionary funding to perform additional preventive maintenance work.
Crack sealing and rut filling.
B-14
Survey Questions 5a through 5d
The 30 respondents that answered “Yes” to question 4 were asked to answer the multiple
parts of question 5. These detailed results are provided below in tables B-7 through B-10.
Additional agency comments are also included where available.
Survey Question 5a
5a. How would you describe your agency’s pavement preservation program? (Check the one answer that is most representative.)
Table B-7. Summarized assessment of pavement reservation program complexity (Question 5a).
Informal (e.g., Districts or others are following sound
pavement preservation practices, but are not doing so under central office direction
and do not have dedicated funding).
Formal (e.g., guidelines or policies dictate the program’s
practices and dedicated funding is used to pay for treatments).
Formal, but without dedicated funds (e.g.,
framework has been established, but no funding has
been secured to support it). 8 of 30 (27 %) 18 of 30 (60 %) 4 of 30 (13 %)
The 30 agencies who indicated that they had an established pavement preservation program in
question #4 responded to question #5a.
Agency Comments:
Regional funding for preventive maintenance is sporadic.
A major component of the agency's 5-Year Transportation Facilities Construction Program.
Currently in the process of testing and refining the policies and practices previously established.
The "program" isn't really a program but a long standing practice of doing some preventive maintenance things because we know we should. It is voluntary for Districts to participate but the funds used are competing against rehabilitation and reconstruction needs, therefore the application is sporadic and only marginally following sound practices. But if I told you we didn't have a program, our Chief Engineer would call me a liar.
B-15
There is some Central Office guidance and monitoring of program, but no to the "formal" guidelines described.
We have had the Substantial Maintenance Program (dedicated funding) in place for about 16 years.
Districts select projects for program but have to comply with guidelines set up by a statewide preservation program.
Currently developing some guidelines for a preventive maintenance program. Have constructed several surface treatments.
We began with dedicated (but restricted use) funds, but now continuing with less funding certainty.
The program has been weakened due to a general lack of funds throughout the state's agencies.
Federal funding can be used for our approved pavement preservation program projects but it comes out of the same pot of money as our 3R projects. There is no specific amount set aside for [the pavement preservation program].
[Our agency] has applied dedicated funding for preventive maintenance of pavements and is considering this practice again in the future.
Survey Question 5b
5b. How long has your pavement preservation program been in place? (Check the one answer that is most representative.)
Table B-8. Summary of the number of years that current pavement preservation programs have been in place (Question 5b).
< 1 year 1 to 3 years 3 to 10 years >10 years 1 of 29 (3 %) 8 of 29 (27 %) 10 of 29 (35 %) 10 of 29 (35 %)
One agency did not specify a particular timeframe, so there are only twenty-nine respondents
included in the statistics displayed in the table.
Agency Comments:
Approximately 1996 in the Northern Region and 2000 for our Central and Southeast Regions.
[Our agency’s] preventive maintenance program is part of our annual Major Maintenance or contract maintenance program.
Prior to 1991, our in-house maintenance folks did nearly all of the preventive maintenance work for flexible pavements for our agency. For political reasons, this
B-16
practice was mandated to be outsourced. Since then, you could say we have a "stand alone" program because it shows up in our STIP and is acknowledged to be a "program" by some managers even though it truly isn't a formal program.
[Our agency’s program] is not a “stand alone” program.
The pavement preventive maintenance program has been in place 4 years.
[Our agency] currently uses federal funds for preservation. Prior to the mid-1990's we used state funds.
A priority programming process was developed in the mid 1960's, in the late 1970's development of [our agency’s] State Pavement Management System (full implementation in 1982), conversion to PC based system in 1988, and web version roll out end of 2004 [or] early 2005.
[Our agency] has practiced informal pavement preservation for many years.
Survey Question 5c
5c. How would you describe the current status of your agency’s pavement preservation program? (Check the one answer that is most representative.)
Table B-9. Summarized assessment of the maturity of agency pavement preservation programs (Question 5c).
Well Established (A large number of
preventive maintenance
projects have been constructed and performance has
been monitored for a number of years).
Moderately Established
(Buy-in has been established. A
moderate number of preventive
maintenance projects have been
constructed).
Somewhat Established (The pavement preservation program is officially in place, but work
continues on buy-in. A small number of
preventive maintenance projects
have been constructed, with more planned).
Early Stages (The program has
officially been outlined and put in
place, and work continues on
establishing buy-in at the SHA management and state legislative
levels).
Just Beginning (Still in the process of establishing a stand-
alone program). 11 of 31 (35 %) 9 of 31 (29 %) 5 of 31 (16 %) 2 of 31 (7 %) 4 of 31 (13 %)
The 31 responses are used to compute the percentages displayed in the table.
Agency Comments:
The subprogram, pavement preventive program, has been officially established in FY 2005 while a number of preventive maintenance projects have been constructed over years.
We have been limping along seal coating and doing some preventive maintenance work using contractors for years, but we are not truly near the levels and formality of having a preventive maintenance program when we had the in-house maintenance folks doing the work. We will remain in this mode until we actually create a formal program with dedicated funds and accountability.
B-17
We have had our pavement preservation program in place and accepted by our upper management.
All preservation projects go through our system; however, we are still working on buy-in.
I doubt that it will ever be a “stand alone” program.
Formal monitoring of individual treatment performance has not been done.
We have a well-established program which includes rehabilitation. We are in the beginning stages of trying chip seals for preventive maintenance in [the western part of our state].
We annually perform approximately 14,000 to 18,000 lane miles (22,500 to 29,000 km) of chip seal and 4,000 lane miles (6,400 km) of light overlays.
Survey Question 5d
5d. How would you describe the current benefits of your pavement preventive maintenance program? (Check the one answer that is most representative.)
Table B-10. Summarized assessment of the benefits being realized by in place preventive maintenance programs (Question 5d).
Observing reduced costs and improved
pavement performance
throughout the network.
Some examples of cost savings
and/or improved pavement
performance have been identified.
It is too early for signs of actual cost savings or improved pavement
performance.
A few trial projects are
either planned or have been constructed. No data are collected yet.
Work continues on establishing
buy-in and overcoming
early obstacles. 10 of 30 (33 %) 6 of 30 (20 %) 11 of 30 (37 %) 1 of 30 (3 %) 2 of 30 (7 %)
The 30 agencies who indicated that they had an established pavement preservation program in
question #4 responded to question #5d.
Agency Comments:
Annual network road profiling indicates improvements.
Severe budget reductions have affected [our agency’s] roadway maintenance contracting capacity, but preventive maintenance continues to exhibit strong benefits in extension of pavement service life for low expenditure per lane mile.
Not much has changed since 1991. The early obstacles are still here, alive and breathing, because of the political pressure for new construction and rehabilitation.
B-18
The overall rating as measured by [the] pavement management system has improved over time.
Justifying funding to maintain existing conditions in the future.
FHWA #1 in Smooth Roads 2002.
Pavement conditions are deteriorating slightly due to a lessening of funding. When funding was available, the program was successful.
We know we have improved pavement conditions. We don't know whether there is a long-term cost-effective performance benefit from doing more chip seals.
System maintained at a high level of service very cost effectively.
Survey Question 6
Listed below are benefits/goals frequently associated with successful pavement preservation programs. Please prioritize your benefits/goals (i.e., in the “Ranking of Benefits/Goals” column, assign a “1” to the most important goal, a “2” to the second most important goal, and so on) and check those boxes that apply to your agency.
A statistical summary of the 35 responses to question 6 is presented in table B-11.
Specifically, the average ranking of all responding agencies is computed and presented in
column one. The second and third columns in table B-11 summarize the number of agencies
who specified “Yes” and “No,” respectively. Individual agency comments associated with this
question are also included below.
Agency Comments:
This is an imperfect ranking at best and is not really an appropriate way to show tradeoffs.
Goal is to maintain our current level of pavements as "Good" for main highways. Indicators are IRI and distress. Combined rating provides a PCI (Pavement Condition Index). Monitored every 2 years.
We will improve customer satisfaction when we improve the pavement conditions.
I think the answer to this question will differ greatly depending on who within the agency you ask it to (Management versus Engineers).
Many of the above benefits/goals are interrelated and would use the same measure to track progression toward the goal. In some instances, measures may be a bit subjective or at least attempted to justify through a broader analysis. For example, I believe we are making more cost effective and better decisions due to our pavement management system, the only way I can show that our pavement condition has improved over time
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without receiving a major influx of funding. In the ranking system, it is difficult to rank both higher customer satisfaction and increased safety, since they are the result of the other benefits/goals.
Table B-11. Summary of prioritized agency goals of their preventive preservation program (Question 6).
Are measures available to track progress toward this goal?
Benefits/Goals
Average of Benefits/Goals Rankings
(1 to 6 rankings where 1 represents the most important) Yes No
Higher customer satisfaction 4.0 (30 responses) 10 20 Better informed decisions 4.5 (30 responses) 9 20 Improved strategies and techniques
4.5 (31 responses) 7 23
Improved pavement conditions
1.8 (31 responses) 29 1
Cost savings 2.7 (31 responses) 19 11 Increased safety 3.2 (30 responses) 17 13 Other(s):
Improved construction quality
Track funds spent on preventive maintenance
5: Individual Agency Ranking Responding agency did not assign a ranking.
1 1
0 0
Survey Question 7
If your agency does not currently have a program, is there interest in creating and implementing one? (Check the one answer that is most representative).
A summary of the Yes/No agency responses to this question are summarized in table B-12.
Although only five agencies indicated in question 4 that they did not have a pavement
preservation program in place (i.e., AR, IL, FL, MS, and ND), nine agencies indicated in this
question that they were interested in “creating and implementing one.” It appears that a couple
of these states answered questions 4 and 7 inconsistently because they feel that their current
program is still considered “informal.” It is important to note that all agencies responding to this
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question stated that they were interested in creating and implementing a program. See the
individual agency comments below for more detailed explanation of the responses.
Table B-12. Summary of agency interest in implementing a pavement preservation program for those agencies currently without a program (Question 7).
Yes No 9 of 9 (100 %) 0 of 9 (0 %)
Agency Comments:
We have a lot of interest in preventive maintenance at many levels within the Department. This interest should be centered around one central group. We should have a go-to group for answers on both suitable treatments and performance of those treatments.
If there is data to support a benefit to having a program, [our agency] is open.
I have answered this question even though I checked Yes on Question #4 because I don't accept that our informal approach to preventive maintenance is adequate. We are teetering on the fence between not having a program and having one. We truly need a program with dedicated funds, linked to our pavement management system, and with the planning and programming of projects directly linked to the pavement design reports for long term maintenance of our facilities.
Some interest by some Districts, but more are not willing to dedicate funds to it.
[Our agency is] currently working on this.
[Our agency] is in the process of initiating a pavement preservation program as part of its integrated Asset Management Program.
Survey Question 8
Which of the following potential obstacles has your agency faced (or do you expect it to face) during the implementation process? Please indicate the status of each by checking the one answer that is most representative for each potential obstacle. If you indicate that you have faced (or expect to face) a particular obstacle, please indicate the degree of difficulty in overcoming the obstacle by choosing a value on a 1 to 10 scale in the last column of the table. Note that a “10” indicates an obstacle that was very difficult to overcome and a “1” indicates an obstacle that was very easy to overcome. Also note that the initial list box values are set to “n/a” = not applicable.
As question 8 focuses on assessing agency experiences with nine different potential
implementation obstacles, the resulting matrix of results is somewhat complex due to the large
amount of collected data. The actual agency-by-agency responses to each included topic are
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summarized in table B-13. It is, however, important to remember that not all agencies provided
a response for each included research topic, and many did not provide quantitative information
that identified the difficulty in overcoming an obstacle (i.e., “difficulty rating”).
A closer look at the computed average ratings (presented in table B-13) finds that the
implementation obstacle with the highest computed difficulty rating of 6.6 is “dealing with the
shift away from worst-first project selection.” Interestingly enough, the second highest rating of
6.3 was associated with “overcoming treatment failures.”
Table B-13. Summary of common implementation obstacles faced by agencies (Question 8).
Potential Obstacles Effectively Overcame
Currently Battling
Foreseen Obstacle
Not Considered an Obstacle
Difficulty Rating (1 = very easy, 10 = very difficult)
Identifying a champion for the pavement preservation program
15 4 2 13 Avg. Rating = 3.0
Dealing with the shift away from worst-first project selection
9 16 7 2 Avg. Rating = 6.6
Gaining commitment from top management
14 8 5 8 Avg. Rating = 4.6
Showing early benefits 9 7 10 8 Avg. Rating = 5.3 Overcoming treatment failures
4 9 13 Avg. Rating = 6.3
Competition between the different industries active in providing materials and contracting for maintenance and rehabilitation treatments
4 9 13 7 Avg. Rating = 5.5
Competition between various suppliers of maintenance treatments
3 8 13 9 Avg. Rating = 5.4
Political lobbying to prevent the use of new maintenance treatments
3 5 7 18 Avg. Rating = 5.1
Public perception 4 9 16 5 Avg. Rating = 5.6 Other(s):
Gaining buy-in to process from Districts.
1
7: Individual Agency Rating
Survey Question 9
If your agency currently has (or is developing) a pavement preservation program, please describe the five most significant obstacles faced (or that you expect to face) while developing the program. That is, what are the five most important obstacles to overcome in
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order to achieve a successful pavement preservation program? Where appropriate, please include a brief description of the actions undertaken to overcome these obstacles, and provide a copy of any applicable written policies/documentation if possible.
For this question, each agency was asked to describe the five most significant obstacles faced
(or expected to be encountered) while developing a pavement preservation program. Each
agency was also asked to describe the actions taken (if applicable) to overcome the identified
obstacles. The detailed agency responses are summarized in table B-14 below.
Survey Question 10
What advice would you give other agencies to help them avoid some of the implementation pitfalls that you have experienced?
For this question, each agency was asked to share their experiences with developing a
pavement preservation program. The detailed agency responses are summarized below
Leave control of pavement preservation with pavement experts and enact reasonable policies for selection of projects that must be adhered to.
Must have dedicated staff to this initiative.
Be sure to establish highly placed champions for preventive maintenance within the agency management to avoid territoriality battles. Educate and sell District management at the highest levels on the benefits of improved serviceability, appearance and ride to be reaped in their own locale through effective pursuit of their own preventive maintenance program. Track the accomplishments as the preventive maintenance program keeps more of the system in good repair.
Fortunately the Chief Engineer mandated the use of preventive maintenance treatments so buy-in from upper management was not a problem. Keep meetings with maintenance small to reduce the number of opinions. Then put it in writing and have upper management sign off on it.
Get a good, robust Pavement Management System and put good people in charge of it. Then use the darn thing. Also, give your Materials Engineers first crack at the pot of money before you let the planners get to it.
Ours was dictated from top management down; so few, if any, internal obstacles.
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to question 9.
OBSTACLE 1
Obstacle: Regional divisions working independently of each other. Action: Meetings, presentations, and recommendations for work by Pavement Manager. Obstacle: Funding. Action: Created funding. Obstacle: Executive buy in. Action: No problem after initial discussions and meetings. Obstacle: Belief by District Maintenance Managers that their repair needs precluded spending on preventive
maintenance. Action: Provided annual pavement condition survey data which disclosed good candidate project locations. Obstacle: Funding. Action: Created funding. Obstacle: Definitions. Action: Numerous opinions between maintenance, engineering, and upper management on how to define
preventive maintenance, when, where, what, etc. Obstacle: The disconnect between Planning/Planners and the Pavement Engineers. Action: When a Materials Engineer designs a pavement, they look at life-cycle and therefore create a map of
long term preventive maintenance and rehab for their design prior to ultimately deciding upon the best candidate. That document then goes in a drawer never to be seen again. That document ought to be the "road map" directly entered into a long range plan earmarked for construction dollars when the timing is appropriate. This is the point at which my agency fails. Thus, planners, MPO's, Board Members, and politicians monopolize the available funding for new construction and reconstruction projects leaving only crumbs for the preventive maintenance jobs.
Obstacle: Proper dedicated funding. Action: Worked with top management at the start to develop a program with dedicated funding. To begin we
had to give up some Maintenance Operator positions. It helped that top management came from Operations and understood the needs and benefits of pavement preservation.
Obstacle: Must overcome "worst first" approach. Action: Constructed demonstration projects and programmed 1 to 2 "pavement preservation demonstration
projects" statewide for the next few years. Obstacle: Funding. Action: Have written justification for funding based on benefits predicted by our pavement management
system. Obstacle: Develop specifications. Action: Completed by research. Obstacle: No hard data to show that a pavement preservation program is more cost effective than what we are
currently doing with current maintenance program. Action: Have setup a couple of test roads to see if we can come up with some data that shows that it is cost
effective to put down a surface treatment while the pavement is in good condition. Obstacle: Developing preventive maintenance specifications for the numerous techniques. Action: Using the NCPP to assist us. Obstacle: Nomination of appropriate candidates Action: [No action noted.] Obstacle: Reactive approach. Action: Training across all Divisions (used NHI courses)
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to question 9 (continued).
OBSTACLE 1 (continued)
Obstacle: Adequate funding. Action: The first year $5 million were set aside for pavement preservation projects. Distribution of moneys in
equitable fashion was also a concern. It was difficult having one District nearly all metropolitan and others low density rural.
Obstacle: Organizational responsibility. Centralized vs. decentralized. Action: Administrative support, good communication, develop consensus. Obstacle: Lack of funding. Using pavement preservation treatments as band aids. Action: [No action noted.]. Obstacle: Top management “buy-in.” Action: Meetings, education, projected cost savings, other states, and National movement.. Obstacle: Funding. Action: Legislators were convinced of the effectiveness of a pavement preservation program. Obstacle: Lack of dedicated funding for preventive maintenance. Action: Provided goals (lane miles) for each District to accomplish concerning preventive maintenance. Obstacle: Lack of funds specifically set aside for pavement preservation program. Action: None. Obstacle: Dedicated funding. Action: Presentations/seminars to senior management to promote the benefit of using preservation
management. Obstacle: Preservation champion. Action: In 1999, [our agency] formed a Statewide Pavement Preservation Committee which consists of upper
managers who have a stake in preservation. This committee sets the program goals, objectives, and guidelines and is responsible for preservation.
Obstacle: Demonstrating the benefits of capturing construction history. Action: [No action noted.] Obstacle: Upper management support to develop, implement and conduct pavement rehabilitation project
selection on the results of the pavement management system. Action: Though it may take years, the ability to verify that the pavement management results simulate actual
pavement performance and results in rehabilitation dates that meet the "engineer's judgment" is pivotal with buy in..
Obstacle: Dedicating funding. Action: [No action noted.]
OBSTACLE 2
Obstacle: Project selection can be affected by political pressures. Action: Project selection criteria has been memorialized in regulation. Obstacle: Linkage to the pavement management system. Action: Developed an integrated pavement management system. Obstacle: Planned strategy and staffing. Action: No problem after dedicated staff obtained.
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to question 9 (continued).
OBSTACLE 2 (continued)
Obstacle: Use of preventive maintenance treatments as a coat of paint on pavement which is in poor condition just to spend funds.
Action: Counseled Pavement Managers during program field reviews preparing for preparation of Districts' annual maintenance programs. Established targets for each District's preventive maintenance program attached to their funding level.
Obstacle: Establishing the benefits of preventive maintenance treatments. Action: Conducted field reviews with maintenance guys to determine added life of various treatments.
Currently checking those assumptions. Obstacle: Ribbon cutting and gold shovels versus having dedicated funding or measurable goals. Action: Planners, MPO's, Board Members, and politicians still dedicate resources on the "worst first" approach
because it provides tangible evidence of their magnificence. If we could lock up the necessary funds for taking care of what we currently have, they would still have plenty to "play with."
Obstacle: Working with PMS in developing a useful tool. Action: Operations actually worked well with the PMS to develop a system that would give us information that
could be used to select projects. PMS information is used to select the annual preservation program. Obstacle: State of the Art non-proprietary preventive maintenance mixes are not part of [our agency’s] standard
mix designs Action: Developing and placing experimental thin lift mixes. Obstacle: Buy-in from District Offices. Action: Assigning a point of contact from our central office with each District to work with them in the
development of their program. Obstacle: Develop QC/QA procedures. Action: Not completed but being addressed. Obstacle: Too many “bad” pavements to take care of. Action: [No action noted.] Obstacle: Developing guidelines for treatment selection. Action: [Our agency’s] Research Division is working on a decision tree based on pavement condition. The
NCPP will review and help us in this process. Obstacle: Political Issues with regard to new treatments. Action: We have struggled with this—we actually ended up with restrictions in Law. We are now much more
active in trying to keep these issues at the engineering level. Obstacle: Changing the "mind set" to work on better highways rather than the ones too far gone. Action: Education of the Maintenance Superintendents. Obstacle: Increased funding. Action: Management buy-in, authorization. Obstacle: Maintaining momentum. Action: As time went by, pavement conditions improved. As funding began to become scarce, maintaining
momentum became a challenge. Obstacle: Worst - first mentality. Action: Provided automated preventive maintenance candidate list generated from the pavement management
database, defining pavement sections that were "good" candidates for preventive maintenance. Obstacle: Learning curve with regards to when pavement preservation is more appropriate than 3R. Action: No formal action.
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to question 9 (continued).
OBSTACLE 2 (continued)
Obstacle: Shift away from worst first. Action: Have had annual or biannual condition rating procedure in place since 1970's. Condition data has
shown that worst first does not work. Also, funding allocations come with lane-mile targets that must be met.
Obstacle: Public perception why funds being expended on good roads. Action: [No action noted.] Obstacle: Accuracy of data. Action: After 30 plus years of collecting pavement management data, this is still one of our bigger challenges.
We are continuing to work with the other entities of the DOT to improve the quality of the data collection/entry process..
Obstacle: Changing philosophy from “worst first.” Action: [No action noted.]
OBSTACLE 3
Obstacle: Lack of interest in pavement maintenance, preservation, and rehabilitation. Action: Continued education of the benefit of preservative activities. Obstacle: Implementation of results into actual work programs. Action: [No action noted.] Obstacle: Major maintenance funding insufficient to support need for large scale preventive maintenance
program as integral part of [the] Pavement Preservation program. Action: Division of Maintenance developed a Budget Change Proposal which established a renewable source
of additional funds to be added to the maintenance program in support of preventive maintenance projects.
Obstacle: Uniformity of when, where, which treatments throughout the state. Action: To monitor the performance of preventive maintenance treatments they need to be applied equally
throughout the state. Based on field meetings with maintenance people, we established some statewide guidelines.
Obstacle: Marketing of the preventive maintenance concept for fun and profit. Action: Selling the Planners, MPO's, Board Members and politicians on the concept of thinking long term and
employing cost effective approaches to our business is the real challenge here. NHI courses don't cut the mustard with these types of people. We need more leadership from FHWA to force changes on folks who are reluctant to give up power and freedom to sprinkle highway money around as they see fit.
Obstacle: Changing the District Personnel from the worst first position. Action: When we started the system was in poor condition and trying to convince the District personnel to use
contract money on good roads took some time to change the culture. Obstacle: The cost of incidentals to the pavement preservation work (design cost, traffic management, police
details, rumble strips, striping, raised markers, etc.) may offset any benefit gained by doing "thin maintenance overlays" rather then thicker less frequent overlays.
Action: Constructing demonstration projects to determine the cost effectiveness/benefit cost of pavement preservation.
Obstacle: Finding money. Action: Districts have a target spending goal.
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to question 9 (continued).
OBSTACLE 3 (continued)
Obstacle: No dedicated funds. Action: [No action noted.] Obstacle: Political pressure from other industry. Action: Other industry (asphalt, concrete) feel that each preventive maintenance project is taking money out of
their pockets. Will need to make sure they understand what we are doing and how they will be affected.
Obstacle: Citizen "outrage" at treating good roads. Action: Need to work on public outreach and education. Citizens do understand the concept of preventive
maintenance from the care of their homes and cars. Obstacle: New asphalt product vendors. Action: Allow vendors to give presentation to Low Volume Road Task Force, provide product on test sections. Obstacle: Finding new pavement preservation champions. Action: Due to retirements, we have lost our last two upper level management pavement preservation
champions. Finding new champions has been a continuing project. Obstacle: Top management buy-in. Action: Industry help, research, and continuous discussion. Obstacle: Other imposed constraints in using federal money (must fix cross-slope or super, etc.) Action: None. Obstacle: Public perception. Action: Promote the cost-effectiveness of implementing preservation management system. Obstacle: Practical information for field decision makers (making condition states understandable). Action: [No action noted.] Obstacle: Though not an obstacle, per se, presentation of pavement management results to clearly express
results. Action: Work with recipients of data to determine their needs. Obstacle: Convincing the public and legislature of benefits. Action: [No action noted.]
OBSTACLE 4
Obstacle: Constructing new and additional facilities puts larger burden on Maintenance Personnel whose funding is decreased regularly.
Action: Identified additional costs with each new project. Obstacle: Integration of pavement preservation activities and routine maintenance activities. Action: [No action noted.] Obstacle: Resistance from project designers to support large scale Capitally funded pavement preservation
projects in the 4-year state plan (State Highway Operation and Protection Plan [SHOPP]). Action: Negotiated with design division on interim rules to allow development of large scale pavement
preservation projects utilizing premium type products (thin application modified binder overlays, microsurfacing, etc.) Began cooperative rewriting and editing of pavement preservation project guidelines which incorporate both heavy maintenance repairs of minor distress and large scale preventive maintenance projects on large expanses of good pavement.
Obstacle: Programming field research into existing pavement management software. Action: Revamped the entire software to include preventive maintenance recommendations. Still in progress.
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to question 9 (continued).
OBSTACLE 4 (continued)
Obstacle: The public does not consider pavement condition in desired maintenance activities. Action: Because the pavement in the system is in very good condition the public puts a higher desire to have
other activities considered, such as litter pick up and increased mowing. The public takes for granted that the pavement will be in good condition.
Obstacle: Convincing decision makers statewide to embrace pavement preservation. Action: Advocating for designated funding specifically for pavement preservation. Obstacle: Improved project selection/planning. Action: Pavement management data is used to select potential projects. Obstacle: Do not know which treatment to use. Action: [No action noted.] Obstacle: Early failures. Action: We plan to be extremely careful in our project selection process to assure we don’t have failures. Obstacle: Funding and funding consistency. Action: We have an upper management that is highly supportive, but this will require long term effort over
multiple political cycles. Obstacle: Public perception. Action: Still working on it, need to hit general public. Provide “success” summaries to legislators. Obstacle: Lack of national studies that conclusively prove the effectiveness of pavement preservation. Action: Most research on pavement preventive maintenance and pavement preservation has been more
anecdotal than empirical. The classic pavement preservation sawtooth graph is more intuitive than factual. We have been pressing for more pavement preservation research on the national level.
Obstacle: Treatment failure. Action: Specified a 3-year warranty. Obstacle: Some good preservation treatments not allowed for federal funding (e.g., Armor Coats). Action: None. Obstacle: Competition between various industries. Action: Establish a reliable measure of expected service life and do life-cycle costing analysis to prove the
cost-effectiveness of certain preventive treatments. Obstacle: Relational (tabular) and spatial (mapping) integration of both inventory and condition assessment. Action: [No action noted.] Obstacle: Gaining unified support from all [agency] Districts. Action: [No action noted.]
OBSTACLE 5
Obstacle: Continual increase in deferred maintenance needs. Action: Continued identification of needs. Obstacle: Tendency of Districts to sweep some of their preventive maintenance allocation into corrective
projects rather than seeking out additional projects. Action: Plan to hold funds in a centralized account to be used in a first come -first served basis in order to
encourage timely development and construction of preventive maintenance projects within the Districts.
Obstacle: Tracking costs/benefits of preventive maintenance treatments. Action: Beginning to collect data.
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Table B-14. Summary of the most significant obstacles to implementing a pavement preservation program as identified by agency responses to Question 9 (continued).
OBSTACLE 5 (continued)
Obstacle: Telling the story to others. Action: We are not good at telling others the success we have had. We are doing better. Obstacle: Convincing decision makers at local levels to embrace pavement preservation. Action: Advocating for designated funding specifically for pavement preservation and implementing
demonstration projects to show benefits. Obstacle: Training. Action: Needed. Obstacle: Buy-in from Districts. Action: Administration supports a preventive maintenance program, therefore this should not be a big concern. Obstacle: Showing benefits. Action: We need more tangible measures. Obstacle: Get field maintenance personnel to implement. Action: Include in District’s betterment program, District Engineers and Maintenance Managers on task forces,
can make decisions. Obstacle: Competitions between suppliers. Action: Establish a reliable measure of expected service life and do life-cycle costing analysis to prove the
cost-effectiveness of certain preventive treatments.
Must stick with the program to do pavement preservation and use resources wisely. You do not need just one champion. All in the agency must buy into the need and benefit. When selecting locations you cannot ignore the worst sections and need to bring them along at the same time until you reach the desired goals for your system. We did not have a problem but the decisions on what maintenance action and where to spend the resources must be left with the manager of the program.
Constructed pilot/demonstration projects in order to learn pavement preservation techniques and to demonstrate to top management the pavement preservation is cost effective.
Need dedicated positions to work on issues, full time.
Get buy-in from top management including the Highway Commission. Develop good information for the general public (i.e., analogous to regular maintenance on your automobile or in a rural state, regular maintenance on farm equipment).
Begin with management support at the highest possible level.
Identify stakeholders, develop consensus.
Get top management buy-in, give person or group heading program authority, and obtain funding.
Secure dedicated funding and fight like heck to protect it. Convince upper level management and legislators that it is more important to preserve the existing infrastructure than to build new infrastructure and then let both the old and the new infrastructure decay.
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To continuously promote the cost-effectiveness of preservation management and gain support from senior management, and convince them to provide dedicated funding to preservation management works.
Do what [our agency] did. Form an upper management Pavement Preservation Committee who are stakeholders in the pavement condition. Get them to establish preservation from the top down.
Compare maintenance cost and pavement levels of service between states that perform and don't perform preventive maintenance.
Determine what it is you want, quantify what you need, ensure that all stake holders are aware of the process, and then address issues in a responsible time frame (i.e. don't make hasty decisions—if incorrect, they often times are challenging to overcome).
Survey Question 11
Does your agency have a dedicated budget for a pavement preservation program? (Check the one answer that is most representative.)
If “Yes,” then, what level of annual funding is dedicated for 2004? (Provide amount or select the one answer below that is most representative.)
Question 11 is a two-part question used to gather details about the amount of money being
dedicated to pavement preservation practices. The first part of the question asks if the agency
has a “dedicated budget” for a pavement preservation program. The detailed responses from all
35 agencies are summarized in table B-15 below.
Table B-15. Summary of agencies with dedicated pavement preservation budgets (Question 11, part 1).
Yes No 19 of 35 (54 %) 16 of 35 (46 %)
In a follow-up question, the respondents that answered “Yes” in part one of the question,
were asked to provide information on the annual funding dedicated for 2004. This detailed 2004
funding information is summarized in table B-16. Additional agency comments associated with
question 11 are also included below.
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Table B-16. Summary of agency funds dedicated to pavement preservation practices in 2004 (Question 11, part 2).
<$10 million $10 to $25 million $25 to $50 million $50 to $75
million >$75 million 4 of 20 (20 %) 3 of 20 (15 %) 7 of 20 (35 %) 0 of 20 (0 %) 6 of 20 (30 %)
While 20 agencies provided detailed budget information in the follow up question, only eighteen
of the 19 that answered “Yes” to the first question provided information. In addition, two
agencies that indicated that they did not have a dedicated budget in the first question provided an
actual budget number in the follow up question. The collected detailed agency comments are
included below.
Agency Comments:
Includes several programs (low-volume, betterments, 3R, etc.)
Each of our 10 Districts has an annual overlay budget and maintenance budget. The Districts are somewhat free to spend the moneys where they feel there is the greatest need. Some Districts are more "progressive" with their approach to preventive maintenance.
The Agency's pavement preventive maintenance program and the pavement preservation program are two separate programs, which have budgets of $5 million and about $90 million, respectively, per year.
Maintenance is privatized and funded monthly with pavement preservation required or dedicated activities as part of the contracts.
Funding provided for 2004 FY strictly for use on preventive maintenance projects. Subject to review by Department of Finance for renewal in the 2005 FY.
Each of the six Districts gets approximately $20 million per year for a resurface program. This includes money for "Preventative Maintenance" treatments, usually mill and thin (1.5-in [38-mm]) overlay. In addition, each District's maintenance section has a preventative maintenance program that includes crack seals and chip seals.
May seem like a lot for an approximate 10,000-mile (16,000-km) system, but these dollars also include rehabilitation efforts.
Our Pavement Management System suggests funding for preventive maintenance, but the actual allocation of this funding is still not fully followed.
Goal of $40 million. Actual spending about $32 million.
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We are using $35 million in STP funds and $40 million is state funds for thin overlays (>2 in [50 mm]) and chip seals. However, I wouldn’t consider this dedicated preventive maintenance funds.
This money is used to fully fund the 14 Division Bituminous units that place chip seals as well as crack sealing and contract pavement preservation work such as slurry seals.
Initial program started at $5 million, then to $8 million, and now over $10 million.
No, it competes with 3R projects for funding.
Funding competes with other capital maintenance and rehabilitation activities.
Includes rehabilitation. We do not have a separate allocation for preventive maintenance.
Scheduled to increase to $265 million in 2006 and $275 million in 2007.
Survey Question 12
If a dedicated funding source is available, how would you characterize the administration and distribution of pavement preservation funds? (Check the one answer that is most representative.)
Question 12 asks the respondents to characterize the distribution of pavement preservation
funds in their agency as “centralized,” “de-centralized,” or as a “combination,” and 21 of 35
agencies responded to this question. The respondent results are summarized in table B-17, and
additional agency comments are included below.
Table B-17. Characterization of the funding administration and distribution methods used by responding agencies (Question 12).
Centralized De-Centralized Combination 11 of 21 (53 %) 3 of 21 (14 %) 7 of 21 (33 %)
Agency Comments:
Comes from Headquarters.
With significant input from each Engineering District during program discussions.
Private contractors in various areas have differing schedules and priorities but Headquarters does monitor activities and provides standards.
Mostly the resources are controlled by Headquarters; however, some funds are left entirely to the Districts. Approximately 90 percent of the resources are controlled by Headquarters.
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The preservation funds are distributed for preservation activities only.
Using pavement condition/management information candidate projects are identified. A field review with District personnel is conducted. Proper scoping of the project is reviewed and adjusted if needed.
Districts, maintenance office, pavement preservation merge programs and from each entity.
The interstate is managed centrally. The non-interstate is centrally managed for dividing funds to the Regions. The Regions then pick the projects using data from the Pavement Management Unit.
Districts are given an allocation from the overall program. They spend it on the roads they decide need preventive maintenance.
[Our agency’s] Districts make the final determination of how funding is expended on pavement maintenance and rehabilitation related activities.
For the 2005-07 budget, [our agency’s] Pavement Management System was fully utilized to select project for rehabilitation. Each Region then had to request and be given approval to deviate from this list.
3.0 SELECTING PAVEMENTS FOR PREVENTIVE MAINTENANCE
Survey Question 13
On what facility types does your agency currently apply preventive maintenance treatments? (Check all that apply in the two columns on the right).
Only two agencies indicated that they did not perform preventive maintenance in at least one
of the roadway classification categories defined in the questionnaire. The respondent results are
summarized in table B-18, and additional agency comments are included below.
Agency Comments:
All types of roadways can and do receive preventive maintenance treatments. These are typically applied at the direction of the District Engineer within the constraints of his/her District overlay program and budget.
[Our agency] encourages preventive maintenance projects throughout its system.
Learning on lower volume system.
Used on any section of pavement in the entire system. We would use a minimum overlay thickness of 2 in (50 mm).
All roads on the state highway system are eligible.
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Table B-18. Summary of facility type characteristics associated with projects selected as candidates for pavement preservation projects (Question 13).
Roadway Setting
Roadway Classification
General ADT Range Associated with Different Roadway Classifications (vehicles per day [vpd]) Rural Urban
Freeway 30,000 and above 29 of 35 (83 %) 26 of 35 (74 %) Arterial 12,000 to 40,000 29 of 35 (83 %) 27 of 35 (77 %)
Collector Road
2,000 to 12,000 29 of 35 (83 %) 27 of 35 (77 %)
Local Road ≤ 2,000 24 of 35 (69 %) 22 of 35 (63 %)
Survey Question 14
Approximately what percent of your preventive maintenance projects are placed on pavements in each of the following condition categories?
Question 14 asks the respondents to identify the percentage of preventive maintenance
projects applied to pavements in very good, good, fair, poor, and very poor condition. Of the 35
agencies responding to the questionnaire, 26 provided detailed percentages for this question.
The detailed respondent results are summarized in table B-19. The last column in this table
presents the average of the 26 agency percentages provided for that particular pavement
condition. Additional agency comments are also included below.
Table B-19. Summary of the percentage of preventive maintenance projects placed on pavements in different condition categories (Question 14).
Pavement Condition
Average Percentage of Preventive Maintenance Projects by Condition Category
Very Good 9.3 Good 25.9 Fair 47.0 Poor 15.3
Very Poor 2.5 Total 100%
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Agency Comments:
We are generally too far behind on corrective maintenance in order to do preventive or preservative maintenance. Thus we call it preventive maintenance.
We have used fog seals and chip seals on lower volume roadways. On concrete Interstate pavements we have used dowel bar retrofits, diamond grinding, and joint sealing. Some of the Interstate routes were probably not acceptable candidates (diamond grinding in particular) for the preventive maintenance treatment selected.
In [our state] the pavement condition and the treatment type defines whether or not the project is preventive maintenance rather than only the treatment strategy.
Sometimes we knowingly use preventive maintenance techniques as a "bandage" to hold together a roadway until we can get a reconstruction project. That's why there is so much in the poor and very poor areas.
Data not currently available.
Approximately 90 percent of the system is in good to very good condition.
Currently funding is not tied to pavement condition, although our system provides this detail.
I do not have the data but most jobs are on good and very good pavements.
We use the surface treatments mostly as a maintenance tool.
Only apply preventive maintenance (chip seals) to low volume and low truck traffic highways.
Pavement management is currently working on these numbers.
Data not available.
Too early to tell since we just started it. But the section's pavement management condition index values can't be in poor or very poor condition and qualify for the program.
Sometime roads in poor condition are chip sealed to "hold them together" until something else can be done.
[Our agency] has very little roadway in the very poor category.
By definition, preventive maintenance treatments are those treatments that are used in a
preventive manner (i.e., applied to a pavement in relatively good condition), while not adding
any structural capacity to the pavement. With this definition in mind, it is interesting to observe
that the results of question 14 show a total of 68.4 percent of preventive maintenance projects
being applied on projects in fair, poor, and very poor condition combined. These results indicate
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that agencies still have differing definitions of preventive maintenance, and therefore, still have a
large variability in the types of projects being selected as candidates for preventive maintenance
projects. Some of the agency comments associated with this question demonstrate this
variability in project selection, as two agencies stated that preventive treatments are often used
on pavements in poor condition to buy additional time until a more substantial rehabilitation
activity can be completed.
Survey Question 15
Does your agency typically apply more than one preventive maintenance treatment before rehabilitation? Check the one answer that is most representative. If you answer “Yes,” please explain.
The 30 responses to this question are summarized in table B-20, and additional agency
comments are included below.
Table B-20. Summary of whether or not agencies apply more than one preventive maintenance treatment over the life of a pavement (Question 15).
Yes No 24 of 30 (80 %) 6 of 30 (20 %)
Agency Comments:
The Northern Region [in our state] places many preventive maintenance surface treatments before rehabilitation is done, especially in permafrost areas.
Depending on the highway system that the treatments are being applied to, there can be several preventive maintenance treatments applied to the same road surface. Several chip seals, followed later by a crack seal, is not uncommon on lower volume pavements. Interstate concrete pavements have undergone numerous iterations of preventive maintenance treatments form joint seals to crack seals to CPR to diamond grinding and even dowel bar retrofits.
We would crack seal on average two times, also perhaps one surface seal before rehab. Pavement condition defines whether or not a project is Preventive Maintenance,
Pavement Preservation (heavy maintenance on minor distress) or rehabilitation (significant rebuilding/updating of a facility due to high pavement distress and/or bad ride).
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Multiple chip seals are placed until a rehab is performed. Many times [our agency] will crack seal, wait a few weeks, and then chip seal the same section.
We usually get to flexible and rigid pavements a couple of times with preventive maintenance projects before we get to the rehab or replacement cycles.
New program, [therefore] data not currently available. After construction we may perform many different preservation before the section
would be reconstructed. Many rural pavements receive more than one chip seal. If you consider crack pour/seal a preventive maintenance treatment the answer is yes,
otherwise no. Low volume roads are sealed until an asphalt overly is required. Once the cracking and
raveling become a problem we schedule for an overlay. In the case of applying a crack seal in the first 3 to 5 years after a project is constructed
and then a chip seal around 7 years and thin overlay around 10 to 12 years. These are three separate pavement preservation treatments that would be performed prior to rehabilitation.
[Our state] has no county road system, so we treat and retreat many low volume roadways.
Too early in program to determine. Three to five treatments over 20-year projected life. A new pavement may be crack sealed a few times, then overlaid with a pavement
preservation treatment and then the cycle would start over. This could happen two to four times.
We could do multiple Armor Coats or thin overlays on many sections before getting into the need for a rehab treatment (medium overlay or higher).
May apply several lifts of microsurfacing or other ultra-thin treatments depending on pavement condition.
Once we get it fair or better, we intend to hold it there and not let it go to poor. Typically roads < 10,000 ADT are chip sealed as many as three or more times before
rehabilitation. Many eventually receive a light overlay after a number of chip seals. Roads are usually prepared for the chip seal or overlay by performing pothole patching, base repairs, level ups or crack sealing.
HMA—The majority of our rehabilitation is in the form of a structural overlay. Normal preventive maintenance consists of crack sealing, dig outs, and minor blade patching for settlement and localized wheel rutting. PCCP—Preventive maintenance consists of repairing spalled areas, panel replacement, and HMA patches over settled panels.
Crack seal at 3 ± years. Additional crack sealing needed thereafter. Sometimes seal coat at 7 to 10 years.
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Survey Question 16
For what purposes do you apply preventive maintenance treatments? (Check all that apply).
To facilitate answering this question, some common purposes of preventive maintenance
were listed from which respondents could choose. The respondent results are summarized in
table B-21, and additional agency comments are included below.
Table B-21. Summary of typical purposes for applying preventive maintenance treatments (Question 16).
Purpose Number of
Respondents Seal surface 30
Reduce water infiltration 28 Increase friction 27
Increase smoothness 21 Reduce rate of deterioration 33
Lane delineation 1 Noise abatement 3
Agency Comments:
Vehicle noise is just becoming an issue for us, but it isn't a criterion just yet.
Increase smoothness (with mill and fill or thin overlays).
4.0 PREVENTIVE MAINTENANCE TREATMENT SELECTION, TIMING, AND PERFORMANCE
Survey Question 17
Which of the following treatments are applied in a preventive manner (i.e., to pavements in good condition)? Check all boxes that apply to indicate the current status of the use of each treatment.
Question 17 asks the respondents to identify the types of preventive maintenance treatments
that were previously used, currently are being used, and are scheduled for use in the future by
their agency. The respondent results are summarized in tables B-22 and B-23 for HMA-surfaced
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and PCC-surfaced pavements, respectively. The numbers highlighted in gray represent the total
number of respondents associated with a particular table cell. Additional agency comments to
this question are also included below each table.
Table B-22. Summary of treatment type usage and interest for treatments on HMA-surfaced pavements (Question 17).
TREATMENTS FOR HOT-MIX ASPHALT (HMA)-SURFACED PAVEMENTS
Treatment Type Completed
Projects Projects In Progress Planned Projects
Interested in Using
Saw and seal or rout and seal cracks 28 15 12 4 Overband crack seal 24 12 10 3 Cape seal 3 2 2 3 Fog seal 16 8 8 3 Scrub seal 7 2 3 5 Slurry seal 17 11 11 4 Rejuvenators 9 4 2 4 Single course microsurfacing 27 15 13 7 Multiple course microsurfacing 17 11 9 6 Single course chip seal 28 16 13 5 Multiple course chip seal 18 10 8 6 Chip seals with polymer-modified asphalt binder 23 11 10 8 Paver-placed surface seal (e.g., Nova Chip) 25 11 13 5 Thin HMA overlay (<40 mm [<1.5 in]) 27 17 16 6 Cold milling and HMA overlay (<40 mm [<1.5 in]) 23 14 14 4 Ultra-thin HMA overlay (<20 mm [<0.75 in]) 11 5 5 6 Hot in-place HMA recycling (<40 mm [<1.5 in]) 17 7 6 4 Cold-in-place recycling 17 8 8 5 Profile milling 21 7 8 3 Ultra-thin whitetopping 10 3 4 8 Underdrain outlet repair and cleaning 18 4 6 2 Other(s):
High Float Surface Treatments Friction Whitetopping Cold-In-Place Recycled Expanded Asphalt Patching Treat Bleeding Coarse Matrix High Binder ACP (CHMB) Permeable Friction Course
1 1 1 1 1 1 1 1
1 1 1 1 1 1
1 1 1 1 1
Agency Comments:
[Our agency] uses a 2-in (50-mm) thin HMA overlay and a 2-in (50-mm) thickness for hot in-place recycling.
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Table B-23. Summary of treatment type usage and interest for treatments on PCC-surfaced pavements (Question 17).
TREATMENTS FOR PORTLAND-CEMENT CONCRETE PAVEMENTS
Treatment Type Completed
Projects Projects In Progress
Planned Projects
Interested in Using
Concrete joint resealing 27 12 12 3 Concrete crack sealing 27 11 10 2 Diamond grinding 30 7 9 3 Diamond grooving 11 1 2 1 Partial-depth concrete pavement repair 27 7 8 2 Full-depth concrete pavement repair 28 10 10 2 Dowel bar retrofit (load-transfer restoration) 22 4 7 2 Thin PCC overlays 8 3 3 5 Underdrain outlet repair and cleaning 18 2 3 3 Other(s):
Pre-cast concrete slab repair Slab Jacking
1
1
1
Agency Comments:
Dowel bar retrofit is considered corrective or restorative, not preventive.
Survey Question 18
Which of these best describe the method your agency uses to select a preventive maintenance treatment for a given pavement? (Check all that apply).
Question 18 asks the respondents to choose a selection method (from a provided list) that
best describes their agency’s method for selecting preventive maintenance treatments.
Obviously, this question is only appropriate for those agencies that stated that they have a
preventive maintenance program in place. The respondent results are summarized in table B-24,
and additional agency comments are included below.
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Table B-24. Summary of methods used by agencies to select a preventive maintenance treatment for a given pavement (Question 18).
Selection Method
Number of Respondents for Each Selection
Method Preset schedule of times 12 Use of a selection matrix based on distress types and severities/extents
21
In-house guidelines 19 Industry guidelines 1 Engineering judgment 28 Cost/benefit analysis 7 Other(s):
Maintenance personnel judgement PMS data Annual Pavement Management Report
1 1 1
Agency Comments:
Usually the folks who select the timing and types of projects have a good idea of what they need to do and when they need to do it.
Currently in demo project phase.
Selection of treatment is made using a first cut selection from PMS, and then actually determined by the District and Headquarters personnel.
It is envisioned through the support and implementation of a research problem statement regarding treatment activity performance that the cost/benefit for each alternative can be determined.
Districts are given an allocation and they determine what roads to apply preventive maintenance treatments to. There are some guidance documents and monitoring by [the Maintenance] division, but Districts make decisions.
For larger projects, these may be identified during the pavement testing and analysis.
Survey Questions 19 and 19a
Question 19 is a two-part question used to assess to what extent pavement management data
is used to influence the selection of preventive maintenance activities. The first part of the
question asks if the selection of pavement preservation activities is “tied” to the agency’s
pavement management system. The detailed responses from the 33 respondents to this question
are summarized in table B-25.
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Survey Question 19
Is the selection of pavement preservation activities tied to your agency’s pavement management system? Check the one answer that is most representative. If you answer “Yes,” please explain.
Table B-25. Summary of agency responses indicating whether or not pavement preservation activities are tied to the agency’s pavement management system (Question 19).
Yes No 23 of 33 (70 %) 10 of 33 (30 %)
Agency Comments:
Maintenance requests for pavement preservation work is checked and approved by the Pavement Engineer.
Only loosely. Districts know what is going to be rehabbed and plan their preventive maintenance activities accordingly. In the future it will be more closely planned by the Central PMS people working with the District people.
The Pavement Condition Survey annually provides Pavement Managers with a record of potential preventive maintenance candidates from which each District prepares its Roadway Maintenance proposals and plan. Engineering judgment and management records help identify, from the candidate list, the best projects for each fiscal year's plan.
Currently in the process of trying to incorporate preventive maintenance treatments into the pavement management system. The current system recommends preventive maintenance treatments, but not to the standards that we would like.
Loosely. They look at age, ride, cracking, roughness, rut depth, and friction number as triggers for more scrutiny.
PMS collects data on an annual basis; the results of the field observations are available for the District and Headquarters personnel to use to make project selections. Approximately 95 percent of the locations are selected by PMS and a treatment is recommended. After which the District and Headquarters select a treatment to be used based on observations and Engineering Judgment. Note the PMS selection is used approximately 50 percent of the time and actual treatment selection may be very close to the PMS selection.
The pavement management database is used to determine which type of rehabilitation is needed and to identify the viable projects.
PMS data selects all pavements that are preventive maintenance candidates.
Pavement condition survey suggests pavement treatments, including pavement preservation.
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Condition ratings are used to identify highway location that meets the "defined" condition for a project to be considered for pavement preservation.
Decision trees based on various pavement performance indicators are used to recommend treatment options.
Annual PMS report may change [the] pre-set schedule in the Proactive Pavement Preservation Program (P4).
Pavement preservation treatments are selected based on a decision tree that uses pavement management condition indexes.
The pavement management system decides rehabilitations and major maintenance (preservation activities), but it does not identify preventive maintenance (routine maintenance) activities. We are currently adding this capability.
There are programs in our PMIS to do "What if" analysis to determine most effective program.
Pavement preservation activities are being done as part of the integrated Asset Management System.
The PMS is used to identify candidate segments that are field verified.
We are working on this.
In the follow-up question, those respondents that answered “Yes” in the first part of the
question were asked to describe any actions that had been taken in their agency to integrate
pavement preservation and pavement management. A summary of the 25 responses to this
follow-up question is presented in table B-26 (2 of the 23 respondents provided more than one
selection in question 19a so there 25 responses in table B-26). Additional agency comments
associated with question 19 are also included below.
Survey Question 19b
If you answered “Yes” to question 19, describe the status of the integration of pavement preservation and pavement management in your agency? (Check the one answer that is most representative.)
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Table B-26. Summary of the status of the integration of pavement preservation and pavement management activities (Question 19a).
Status of Integration Number of Respondents for Each Integration Category
Completely integrated 7 Currently in the process 7
In-house guidelines 8 Plans for integration 1
Interested 2 No interest 0
Agency Comments:
We are behind on needed rehabilitation and that makes it hard to focus on putting money into areas that are without major needs for work.
Since 1991 we have been "interested," but we are still "kicking the tires" and irritating the salesman in 2004.
Use the information in PMS to optimize our selection of individual projects.
As described above, treatments are selected based on pavement management condition indexes. But, projects are not selected/programmed based on a pavement management analysis (i.e., benefit/cost analysis, optimization, etc.) The Field Maintenance Engineers select which sections they want to include as pavement preservation projects and then check a set of decision trees to see which treatment is recommended for pavement preservation. If the condition indexes fall below certain minimum values, the section does not qualify for the pavement preservation program.
Region picks the projects; however Pavement Management Unit works with each Region to pick the best projects. This process was developed by Statewide Pavements Committee.
The principles of pavement preservation are guiding development of the pavement management models in the Asset Management System.
Survey Question 20
Which best describes the method your agency uses to time the placement of preventive maintenance treatments? Check the one answer that is most representative. Please provide a brief explanation, if necessary.
Question 20 asks the respondents to identify a method from the provided list that best defines
their agency’s process used to select the timing of preventive maintenance treatments, and is
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only appropriate for those agencies that stated that they have a preventive maintenance program
in place. While 38 responses were documented for this question, they were generated by a total
of 32 different agencies (i.e., four agencies had more than one entry). The responses are
summarized in table B-27, and additional agency comments are included below.
Table B-27. Summary of methods used to select the timing of preventive maintenance treatments (Question 20).
Timing Method
Number of Respondents Associated With Each
Timing Method
Predetermined timetable 5 Triggered when minimal distress appears 15 Placed when distress reaches a medium severity level 12 Others (see Agency comments below for more details) 6
Agency Comments:
[Treatments are] placed when distress reaches medium to significant level.
Predefined decision trees. Implementation in progress.
Each District uses a decision tree to identify potential projects in their 5- and 10-year plans. This initial long range plan is to be modified regularly in response to actual pavement performance to keep preventive maintenance work on good pavement whenever possible.
Engineering judgment.
A combination of above factors.
Both [a “predetermined timetable” and “triggered when minimal distress appears”] have been used.
Pavement condition survey will begin indicating treatment at low severity. Treatment types change and urgency changes when distress is more severe.
Sections can have light to moderate distress levels.
Typically driven by individual distress deterioration (i.e., raveling).
Combination of all the above plus engineering judgment.
Again, it is up to the District, but most plan roads where minimal distress is apparent.
Treatments are identified for candidate projects; field personnel make the final determination.
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Survey Question 21
Do you use a pavement management system or maintenance management system data to optimize the timing of preventive maintenance treatments? Check the one answer that is most representative.
Question 21 asks the respondents to identify whether or not they use pavement management
system or maintenance management system data to optimize help determine the timing of
preventive maintenance treatments. The results from the 33 respondents are summarized in table
B-28, and additional agency comments are included below.
Table B-28. Summary of whether or not agencies use pavement management data to optimize the timing of preventive maintenance treatments (Question 21).
Yes No 15 of 33 (45 %) 18 of 33 (55 %)
Agency Comments:
The Pavement Management System is used to develop recommended preventive maintenance and rehabilitation.
Implementation in progress.
Our Pavement Management System and the support staff aren't doing nearly enough work to move into the new millennium and find out what services they can provide to our Districts. Coup attempts by my staff have been thwarted several times. As for our ancient Maintenance Management System, it came across the prairie in a covered wagon and is due for the rest home any day now.
We have a maintenance management system, but it's not used to schedule preventative maintenance.
Main reason to use the PMS information.
Need to do this, but not there yet.
Recently developed software in our pavement management system will be used more in future years to optimize the timing of preventive maintenance.
Our pavement management system outputs a recommended work program but it has not been used for actual project selection and programming yet.
Use PMS to time treatment before pavement falls to poor.
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Survey Question 22
Does your agency currently track the performance of preventive maintenance treatments? (Check the one answer that is most representative.)
The 34 responses to this question are summarized in table B-29. As a follow up question, if
the respondent answered “Yes” to question 22, they were then asked to describe their
performance tracking system. If the respondent indicated that preventive maintenance
performance was not tracked by answering “No” to question 22, they were then asked to describe
any plans for monitoring treatment performance in the future. Detailed comments are
summarized below.
Table B-29. Summary of whether or not agencies track the performance of their preventive maintenance treatments (Question 22).
Yes No 18 of 34 (53 %) 16 of 34 (47 %)
If “Yes,” then describe your agency’s performance tracking system. Also, if you do track performance, how often do you conduct surveys (or run reports)?
Annual road profiling getting IRI and rut depth for each section are reported annually.
PMS, ad hoc.
[Our agency] currently tracks the performance of its 1-year preventive maintenance warranty projects. The Pavement Management System is developing a strategy and methodology to enable regular tracking of pavement performance throughout the roadway system.
Just beginning to review data on past projects and record information on current/planned projects.
[Our agency] does an annual pavement condition survey (ride, rut, and crack measurements) of all state-maintained pavements. There is no specific tracking of preventative maintenance since there is very little if any done.
We collect Pavement Quality Index and International Roughness Index data on all of our roads on a 2-year cycle.
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We review the performance of the treatments by observation. The system is of an age that underlying conditions in some sections may have an affect on the treatment performance.
Periodic pavement evaluation of Highway System [on a] 2- to 3-year cycle.
We are just starting to track maintenance activities. We have traditionally only tracked overlays and rehabilitation efforts.
All pavements are rated for the PMS. Analysis of the data can be improved.
Interstate and expressways are surveyed every year, while other highways are surveyed every other year.
List of treatment selections and their wear rates. Annually.
PMS, annual reviews of chip seals, overlays, and 3R programs.
Pavement condition rating is collected annually; ride quality is collected on an annual basis for Interstate routes, and biannually otherwise.
Pavement evaluation is completed every 2 years, with special requests on skid, IRI ,and rut measures on an annual basis.
Bi-annually.
Districts monitor life of treatments informally. Frequently they develop maps. It is not done formally nor are there reports developed.
If “No,” describe any plans to begin to monitor treatment performance.
Pavement Management will be used to monitor the performance of these treatments in the future. Performance data is already being collected but we do not currently use the data to monitor individual surface treatments. We are working towards that goal.
Inspections are undertaken at District level.
[Our agency] will be tracking the 27 projects that will be constructed this fiscal year.
No plans at present time. Do some informal checks.
Once our preventive maintenance program is in place we will track the performance thru [our agency’s] Pavement Management System.
Starting to.
Need to make this a regular monitoring, rather than a study in response to the perception of decreased performance.
Tracking system currently under development.
A research problem statement has been written that will support the development of maintenance treatment performance.
The Pavement Management staff is working with Maintenance to collect specific locations of maintenance treatments, track condition over time, and hopefully, develop prediction capabilities of maintenance treatments.
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Survey Question 23
Have you analyzed your treatment data to estimate an expected life of your preventive maintenance treatments? Check the one answer that is most representative. If “Yes,” please summarize the expected treatment lives below.
If the respondent answered “Yes” to this initial question, they were then asked to summarize
the treatment lives that they had estimated. The 34 responses to the initial question are
summarized in table B-30. The detailed agency respondent comments are also summarized
below.
Table B-30. Summary of whether or not agencies have analyzed treatment data to estimate expected treatment lives (Question 23).
Yes No 14 of 34 (41 %) 20 of 34 (59 %)
Agency Comments:
Using IRI and rut data, the average life of any treatment can be found.
Chip seals and slurry seals, crack sealing, fog seals—2 to 5 years; thin blankets (modified binder types)—5 to 7 years.
Initial assumptions have been made; we need to review these assumptions for accuracy.
In PMS we have tried to teach the system how long various treatments will last under the many different conditions affecting the pavements.
We have only done this with a small data set and expect our treatments to add 2 to 4 years of life.
The Research Division is looking into this.
Starting to.
Only done intermittently.
We are in the very beginning stages of this activity.
Chip seal—4 to 6 years; slurry seal—3 to 5 years; crack sealing—2 to 3 years; 2-in overlay—5 to 8 years.
Data is being analyzed under a current research project.
It has not been a formal analysis but we have checked our condition data to see if we get the treatment life that our field engineers estimate. We expect: Armor Coat or Chip Seal—7 years; microsurfacing—8 years; thin overlay—10 years. The JCP treatments in
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general have a longer expected life because the next treatment would typically be a different type of treatment. For example, a dowel bar retrofit may last 20 years because the next treatment might be reconstruction or unbonded overlay.
Typical life of a seal coat is 5 to 8 years, depending upon condition of the road prior to placement, traffic, soil types, weather, etc. Typical life of a light overlay is 5 to 10 years, again depending upon the condition of the road prior to placement, traffic and, quality of ACP.
Rut fill projects are expected to last 5 years.
Survey Question 24
What are some pavement preservation treatment-related success stories that you would like to share with other SHAs?
The responses are summarized below.
[In our state,] the Northern Region's extensive annual program involving surface treatments, crack sealing, banding, and hot-mix patching that has basically halted ride quality degradation of their large region.
Just starting.
Good use of seal coats and microsurfacing as well as crack sealing. The hot in-place recycling is considered a rehab treatment.
Use of a thin layer, high binder content Rubberized AC friction course as a seal coat on rural Interstate 5 and 40, as well as State Route 99 (all warranty projects), are still performing extremely well with minimal to no distress from 2 to 4 years after construction, in harsh climates and under high traffic volumes.
Large success with chip seal life on low volume roads. Many of these roads were built 30+ years ago and are in great shape due to chip seals extending the pavement's life.
Preventive maintenance treatments work. We have seen it happen. No heart tugging stories are available [about] these projects.
Do not stick to just one treatment to fix all conditions. Be willing to try new products and methods.
We can build a good chip seal.
Within the past five years, [our state] has more than doubled the number of miles treated with chip seals.
Chip seals on fair to good roadways result in a very pleasing surface, with good ride quality.
Microsurfacing and Novachip [have provided] Good results.
$20 to 40 million annual savings; #1 FHWA smooth roads.
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We implemented a successful pavement preservation program from 1992 to 1998. Our conditions improved dramatically.
We have done dowel bar retrofit and diamond grind projects on interstates that are performing well. Some good early results with Nova Chip.
Microsurfacing improved moderate to severe raveled pavement surfaces.
I think our best success is that the Regions trust our data and judgment and work with us to try to maintain the best possible pavement condition for the funds available.
Use of emulsion with polymers and asphalt cements with tire rubber for seal coats. Has almost eliminated problem with flying rock.
Rut filling on the interstate in the travel lane extends the pavement life while reducing hydroplaning potential.
Survey Question 25
Do you have any pavement preservation treatment-related failures or setbacks that you would like to share with other SHAs?
The responses are summarized below.
Good performing studded tire wear/rut resistant pavement is not yet found for the Anchorage area though many types have been tried and prematurely failed. Hard aggregate mixes seem the key, but availability is a problem.
Some [microsurfacing] has failed.
Severe budget cutbacks severely eroded our ability to place preventive maintenance projects on some very good candidates at their optimal timing. Renewed funding gives us another chance to optimize this timing of good preventive maintenance projects.
Placed a [microsurfacing treatment] on the interstate, 1 day later maintenance was called out to scrape it off and we overlaid it. A contract crack seal paid on material basis where they "painted" the road, after the first winter the plows scraped the crack seals such that they were flapping in the breeze. Whole section was overlaid that summer.
Hot-in-place recycling hasn't worked here. Seems to me that if the existing pavement is [poor material], heating it up and grinding it to bits and relaying it, won't change that. We've tried adding new aggregate, new mix, and rejuvenators and the pavement which was [poor material] to begin with continued to be [poor material] no matter how much money we tried to spend on it. [Poor material] is [poor material]! If it’s good enough to recycle, you don't need the expense of a hot-in-place project to spruce it up. Hot-in-place recycling has never made any sense to me and I keep thinking I am missing something because people keep doing it.
Yes, we have had failures because the wrong treatment was selected. We just admit we made the wrong selection, fix the failure, and move on, learning from our errors.
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Without some failures you are not doing the minimum actions and are more like reconstruction.
If your existing pavement has un-uniform crown and/or structural cross section, extra precautions need to be taken when in-place recycling project is being planned.
Since 1999, our pavement preservation efforts have lessened due to decreased funding and our pavement scores have suffered.
We have had lots of problems with stripping on cold recycling several years ago. We have also had some problems with 1.5-in (38 mm) treatments delaminating.
Always have the occasional failure. Usually related to material quality or poor construction technique.
Poorly routed crack seals or sealant placed in poor conditions.
Sealing individual cracks that are not related to reflective or thermal cracking. We do not have an effective nor efficient process for sealing cracks related to stress cracking due to traffic loading.
5.0 OBTAINING QUALITY TREATMENTS
Survey Questions 26 and 26a
Question 26 asks the respondents to describe the current quality of their agency’s preventive
maintenance treatment specifications. The 34 responses to this question are summarized in table
B-31 (based on 33 responding agencies, with one agency selecting two different categories).
In a follow-up question (question 26a) those agencies that have specifications are asked to
explain whether they were developed in house or modified from industry publications. The
detailed agency responses to both of these questions are summarized below.
Survey Question 26
How would you describe your pavement preventive maintenance treatment specifications? (Check the one answer that is most representative).
Agency Comments:
Treatments seem to work best when done by State Maintenance personnel. Once put in specifications to contractors, problems become apparent.
The Department is constantly reviewing procedures and specifications to determine the adequacy of all surface treatment specifications.
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Table B-31. Summary of agency assessment of the quality of their preventive maintenance treatment specifications (Question 26).
Status of Treatment
Specifications
Number of Respondents by
Category Recent [up-to-date] 12
Adequate 10 Need improvement 12
Out of date 0 Non-existent 0
[Our agency’s] focus has been on HMA and considers its HMA specifications up-to-date. Other areas such as microsurfacing are non-existent since [our agency] does not use this technique.
[Our agency] will be reviewing the specifications once the latest projects are constructed to reflect any necessary changes to techniques or materials.
Basically the same as our new construction requirements.
Our specifications were modified from industry specifications.
To have an adequate preventive maintenance program we need to raise the bar to require better performance of the industry.
Currently, we have research projects or proposed research projects on aggregates, rolling, and polymer modification. All projects are aimed at improving specifications.
We review our paving and chip seal specification annually.
Rewrote specification manual in 2004.
Survey Question 26a
If you have specifications, were they developed in house or modified from industry publications? Please explain.
Mostly developed in-house with reference to other agency's specifications and industry publications.
Some of the specifications may have come from industry publications, but through the in-house review process they are adapted to provide the performance intended.
In-house.
Developed in-house with interaction and cooperation from industry.
Both.
Yes to both.
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Base specifications were in-house, and modified with industry assistance.
Both.
Actually from both; mostly we have tried to work with industry in specification development.
Industry Specifications were starting point. In-house modifications are made as necessary.
We have developed specs in-house using information provided by industry.
Developed in-house from generic industry information.
Mostly modified industry publications; a few developed in-house.
In-house.
Developed in-house.
We've had in-house specifications around for a long time and these were used by maintenance forces for years. With a preventive maintenance budget we are looking to modify industry standards as we feel are needed.
In-house using input from industry.
Developed in-house.
Both (i.e., developed both in-house and modified from industry publications).
We worked with industry representatives to develop our pavement preservation specifications.
Jointly developed by industry and DOT.
Usually modified from industry publications and updated based on experience.
In-house.
Both.
In-house with industry input.
Specifications developed with input from both the Materials Division, Virginia Transportation Research Council, and Industry.
Both.
Developed in-house.
Some of both.
Survey Question 27
Does your agency have in place quality control/quality assurance (QC/QA) procedures for preventive maintenance applications? (Check the one answer that is most representative.)
B-55
Question 27 is a two-part question used to determine whether or not the responding agencies
have in place quality control/quality assurance (QC/QA) procedures for preventive maintenance
applications. The first question is a simple Yes/No question asking the agencies if they have
such preventive maintenance-related QC/QA specifications, and it elicited 35 responses that are
summarized in table B-32.
Table B-32. Summary of whether or not agencies have QC/QA procedures in place for preventive maintenance treatments (Question 27).
Yes No 24 of 35 (69 %) 11 of 35 (31 %)
If the agency responded “Yes” to the first question, a follow up question asks the respondent
to describe the formality of these specifications (i.e., informal versus formal). If the agency
responded “No” to the first question, a follow up question asks the respondent if their agency has
plans for implementing QC/QA procedures. The detailed agency responses are summarized
below.
If “Yes,” would you describe these QC/QA procedures as informal or formal?
Formal when done by contract. Informal when done by state personnel.
QC/QA procedures for preventive maintenance applications for concrete and asphalt pavements are formal.
Formal for major applications.
Formal for maintenance contractor; i.e. QC/QA plan.
Formal.
For large projects.
Formal. Most of our pavement projects have a QC/QA component to them. The odd jobs like crack seals don't.
We use QC/QA in our HMA treatments. Also all HMA treatments use the Superpave specifications.
Formal.
B-56
Formal for HMA applications, but informal for crack sealing and other treatments.
We need to improve the QC/QA procedures.
Ride Specification on most projects.
The QC/QA procedure is formal. [Our agency’s] State Bituminous Coordinator is required to check a minimum of 10 percent of the roads treated with chip seals by force account work.
Inspectors on site.
Formal.
We have formal procedures for the materials QC/QA. The procedures for placement are probably not enforced well for maintenance treatments.
Formal.
Formal.
Formal.
Olympic Region: (Informal) Maintenance BST projects require aggregate and emulsions be tested for compliance. Construction procedures monitored by Region Maintenance and Materials.
If “No,” what are your plans for implementing QC/QA procedures?
Currently using method specifications.
Are implementing a new specification for chip seals.
Will be included in new specifications and guidelines.
Awaiting AASHTO or other guidelines.
No plans.
None. [The DOT] does quality control.
Survey Question 28
Does your agency use warranty specifications on any of your preventive maintenance treatments? (Check the one answer that is most representative.)
Question 28 is a two-part question used to assess the responding agencies experience and
interest in implementing warranty specifications for their preventive maintenance treatments.
The first question simply asks the agencies if they use warranty specifications on any of their
B-57
preventive maintenance treatments. The 35 responses to this question are presented in table B-
33.
Table B-33. Summary of agency usage of warranty specifications with preventive maintenance treatments (Question 28).
Yes No 7 of 35 (20 %) 28 of 35 (80 %)
If the agency responds “No” to the first question, a follow up question asks the respondent if
their agency has plans/interest in exploring the use of such warranties. The detailed agency
responses are summarized below.
If “No,” do you have any plans/interest of exploring the use of warranties? Please explain.
We are interested.
Not in the near future.
Only used on research projects.
Yes.
Not sure if we are moving towards warranties. We've talked about it but there is reluctance on the part of management to try it.
No.
Certain types of treatments ([microsurfacing]) are being looked at for warranty.
In most cases the treatment works but the failure comes from what is below the surface. We do not believe the contractor can warranty if he is unable to control what is below the surface.
We do not have plans for use of warranties in the future.
We did use a warranty for joint sealant material on one project.
Rout and seal projects often use a 2-year warranty.
No interest at this time.
We are considering warranty specifications.
Yes, we are interested. While [our agency] does a lot of preventive maintenance work with our own forces, there is the possibility of contracting out more work.
We have developed for some future work in 2005, a microsurfacing warranty specification.
B-58
Have interest and plan to explore use of warranties.
Need to develop wording to get contractor back if failure.
Only for chip seals.
Not that I am aware of.
[Our agency] has a 1-year warranty on concrete patching.
No. Too many variables.
Survey Question 29
Has your agency implemented any performance-related specifications associated with preventive-maintenance treatments? (Check the one answer that is most representative.)
Question 29 is a two-part question used to assess the responding agencies experience and
interest in implementing performance-related specifications (PRS) for their preventive
maintenance treatments. The first question simply asks the agencies if they use performance-
related specifications with any of their preventive maintenance treatments. A summary of the 35
responses to this question is presented in table B-34.
Table B-34. Summary of agency usage of performance-related specifications with preventive maintenance treatments (Question 29).
Yes No 4 of 34 (12 %) 30 of 34 (88 %)
After answering the initial question, the respondents were asked a follow up question. For
positive responses to the first question, the follow up question asks the respondent to identify the
treatments for which these specifications have been implemented, and to describe the experience
with these specifications. If the agency responded “No” to the first question, the follow up
question asks the respondent if their agency has plans for implementing performance-related
specifications. The detailed agency responses are summarized below.
If “Yes,” for which treatments? Briefly describe your experience with these specifications.
B-59
Chip seal—[Our agency is] presently evaluating.
Only for chip seal.
Patching on concrete. Ride quality incentive/disincentives on overlays. [Our agency] has also initiated the use of end result specifications for concrete construction.
If “No,” do you have plans for implementing performance-related specifications?
Not at this time.
Not in the near future.
[Our agency] continues research which is geared towards development of performance-related specifications.
No.
No plans that I am aware of.
No.
No.
Have looked at these types of specifications but are unwilling to try because the performance of any treatment is dependent on the materials below the surface.
No plans at this time.
No.
I do not know.
We are considering performance-related specifications.
We would like to pursue with our chip seal applications.
We will be reviewing our maintenance emulsion provisions with the possibility of performance-related specifications being included. Emulsion can meet specifications, but if it does not perform properly in the field application, what have you gained?
Ride quality.
No.
Yes, same as #28 (i.e., “Need to develop wording to get contractor back if failure.”)
No.
No.
Currently exploring opportunities for performance-related specifications.
No.
No.
No.
B-60
Survey Question 30
What is your familiarity with the four pavement preservation courses developed for the National Highway Institute (NHI)? (Check the one answer that is most representative).
This question asks the respondents about their familiarity with the four pavement
preservation courses developed for the National Highway Institute (NHI). The 34 responses to
this question are summarized in table B-35 and additional comments are summarized below.
Table B-35. Summary of the familiarity with the four NHI pavement preservation courses (Question 30).
Level of Familiarity with NHI Preservation Courses
Number of Respondents by
Category Have conducted one or more courses 21
Plans for conducting one or more courses 1 Aware of courses, but no plans on conducting 8
Not aware of courses, but interested 4 Aware, but not interested 0
Agency Comments:
The NHI courses are good, but planners and politicians won't go to them so we don't make any progress toward adopting preventive maintenance strategies as the norm.
In general they have been helpful.
Have conducted several courses.
Very informative, educational.
Survey Question 31
Has your agency trained personnel on preventive maintenance concepts and/or techniques? Please explain.
Question 31 asks the respondent if their agency has trained personnel on preventive
maintenance concepts and/or techniques. If so, the respondent is asked to describe the specific
B-61
type of training that has been conducted. The 31 responses to this question are summarized in
table B-36 and additional comments are also summarized below.
Table B-36. Summary of whether or not agencies have trained personnel on preventive maintenance concepts and/or techniques (Question 31).
Yes No 27 of 31 (87 %) 4 of 31 (13 %)
Agency Comments:
Yes—State Maintenance personnel are trained, but some engineers and supervisors need training.
District and Central Office maintenance personnel are trained in the techniques of some preventive maintenance treatments. This training is typically performed in-house.
Yes.
Yes, Asphalt Institute training about 2 years ago.
In annual conferences with Maintenance Engineers and their Pavement Managers the importance and roots of preventive maintenance are presented along with the state of the art in treatments and methods.
Yes, one NHI class for Pavement Managers, Materials Engineers, and a few maintenance folks.
Yes. We have had general preventive maintenance courses and our field folks have access to technical training on the preventive maintenance techniques through our T2 Center.
A brief course was held to familiarize local government and DOT personnel on the various techniques.
We have no formal training for pavement maintenance treatments and learn from OJT [on-the-job training].
Yes, in-house workshops and NHI training.
Yes, at annual maintenance seminars.
All training is informal.
Only through the NHI courses.
Yes. NHI courses and MS Industry Programs.
Yes. Many of our field personnel have taken the first two NHI pavement preservation courses.
We have developed and distributed our Pavement Maintenance Manual to all maintenance personnel. It defines 1) types of pavement maintenance, 2) PMS
B-62
information, 3) Distress Identification, 4) Pavement Maintenance Treatments, and 5) Recommended Treatment Practices. The FHWA Distress Identification Manual is in wide distribution.
Yes, as part of regular training program.
Through presentations and Task Force members training their staffs.
Yes. We have hosted NHI courses and we have given courses in conjunction with industry representatives.
Yes. We partnered with industry.
Yes. We have had one or two NHI courses here.
We promote the preventive maintenance concepts through internal seminars and workshops.
Two regional annual "Seal Coat Conferences" are held across the State. They are developed jointly with the [State] Asphalt Pavement Association and [our agency].
[The NHI Course titled] Techniques for Pavement Rehabilitation (13108) was completed.
Informal jobsite training and discussion as preventive maintenance work is being done.
Survey Question 32
Does your agency have a technician certification program that includes preventive maintenance treatments?
The 31 responses to this question are summarized in table B-37 and additional agency
respondent comments are also summarized below.
Table B-37. Summary of whether or not agencies have a technician certification program that includes preventive maintenance treatments (Question 32).
Yes No 3 of 31 (10 %) 28 of 31 (90 %)
Agency Comments:
No. We spend too much time on construction inspector materials testing certification as it is.
No. We use our Engineering Technicians to inspect the treatments, most of [whom] are trained in some of the aspects of preventative maintenance treatments but not specifically for preventative maintenance.
B-63
No, although we do have a technician certification program for HMA placement.
No, but we need it.
Yes, for the sampling and testing of materials and for profilograph operations.
Yes, as it applies to materials testing.
[Our agency] has a technician certification program; however, it does not cover preventive maintenance treatments.
Yes, for asphaltic concrete pavement testing, but none for chip seals or microsurfacing.
Survey Question 33
What additional training needs have been identified that are not currently being met within your agency?
The detailed agency responses to this question are summarized below.
Training in pavement preservation.
None.
Always a need for training in asphalt technology, from pavement design, to materials and mix design, to rehab and maintenance methods and materials.
Construction inspection training and in depth preventive maintenance treatment design training for preventive maintenance strategies.
Once the guidelines have been established, training of the regional engineers and maintenance people on the basic theory of preventive maintenance (NHI course) plus education on [our agency’s] specific rules.
We need to get hands-on training on preventive maintenance techniques that our forces would be doing. Likewise for inspectors on contracted preventive maintenance work.
None at this time.
None. We believe we have enough trained personnel to meet our needs. When we are short of inspection personnel we have hired consultant inspection.
Pavement preservation techniques and materials. What other Agencies are doing and their success stories.
None identified at this time.
Training for preventive maintenance treatment applicators (contractors and [our agency]) as well as inspection procedures.
Training for inspectors and maintenance workers.
None.
Optimizing the state roadway network, optimal timing of maintenance treatments.
B-64
We want to host the third and fourth NHI courses on Pavement Preservation.
We need to train technicians on how to monitor the placement of materials and in some of the newer techniques/materials (e.g., Nova Chip, permeable friction course).
None.
Training is always necessary because of turnover of employees. We recently published a "Seal Coat” manual and have had many meetings with the seal coat committee of the [State] Asphalt Pavement Association. Training is needed for contractor and state force equipment operators and department inspectors. [Our agency] is in the process of requesting proposals for a [State] Pavement Preservation Center. Their primary purpose, at least initially, will be for training on preventive maintenance applications.
Basic knowledge of HMA (e.g., its design, characteristics, and proper application).
B-65
B-66
APPENDIX A. PAVEMENT PRESERVATION SURVEY QUESTIONNAIRE
Introduction
Many State highway agencies (SHAs) are in the process of developing and improving pavement preservation programs. As part of those processes, there has been widespread interest among SHAs in learning about ongoing research activities by others and in identifying immediate research needs that would help to improve their programs. NCHRP Project 20-07 is helping to address these needs in the following manner:
Synthesizing existing research activities and findings in pavement preservation.
Developing fundamental and applied research plans for improved consistency and performance of existing treatments.
Identifying future research initiatives to create processes and products to advance pavement preservation.
The purpose of this questionnaire is to obtain current pavement preservation-related information from North American practitioners. Such updated information will be used in a comprehensive summary of the current status of ongoing pavement preservation activities (i.e., implementation status, ongoing preventive maintenance research, treatment selection and timing practices, SHA experiences [successes and failures], and so on). The survey results will also be used to develop a comprehensive list of future research needs and help to prioritize them for future funding. You are being asked to complete this questionnaire because of your background and familiarity with your agency’s pavement preservation practices. If you feel someone else within your organization is more qualified, please pass this on to them. Thank you for your assistance. Questionnaire Level of Effort: This questionnaire has been automated so that all responses can be either checked off or typed into the spaces that are provided. Alternatively, a version can be printed out and responses can be written in. We estimate that responding to this questionnaire should take approximately 2 to 4 hours of your time, at most. Responses or questions regarding the completion of this response should be e-mailed to: [email protected] or [email protected] or mailed to: David Peshkin Applied Pavement Technology, Inc. 3010 Woodcreek Drive, Suite J Downers Grove, IL 60515 Please return this questionnaire by July 15, 2004, and thank you for your assistance.
A-1
Questionnaire Respondent Information
Please provide some general information about yourself and your experience with pavement preservation:
Name:
Title:
Mailing address:
Phone number:
E-mail:
Pavement preservation experience/background:
Definitions Used in the Survey
Several terms are used throughout this questionnaire. The following definitions are provided for the sake of consistency and not as an attempt to be definitive about the meaning of any of these terms. Pavement Preservation—A program employing a network level, long-term strategy that enhances functional pavement performance by using an integrated, cost-effective set of practices that extend pavement life, improve safety, and meet motorist expectations.
Pavement Preventive Maintenance—A planned strategy of cost-effective treatments applied to an existing roadway system and its appurtenances that preserves the system, retards future deterioration, and maintains or improves the functional condition of the system (without increasing the structural capacity).
Preventive Maintenance Treatment—Any individual maintenance activity that is used in a preventive manner (i.e., applied to a pavement in relatively good condition), while not adding any structural capacity to the pavement. Examples, of preventive maintenance treatments include crack sealing and joint resealing, fog seals, chip seals, slurry seals, microsurfacing, dowel bar retrofitting, diamond grinding, and so on.
A-2
1.0 Pavement Preservation-Related Research
1. How would you describe your agency’s familiarity with the pavement preservation and preventive maintenance research being conducted by other agencies? (Check the one answer that is most representative).
Very familiar Somewhat familiar Minimal knowledge No knowledge
Comments:
2. Would knowing about ongoing pavement preservation-related research in other agencies influence the research undertaken by your agency? (Check the one answer that is most representative).
Yes No
Comments:
3. Please use the following matrix to describe the details of your past, current, and future research activities and interests (check all that apply). If you indicate that you have interest in a particular topic, please indicate the degree of this interest by assigning an interest ranking (on a 1 to 10 scale) in the last column of the table. On the next page, please include any corresponding details that better explain your ongoing research activities or interests.
Topi
c ID
Research Area/Topic Con
duct
ed P
ast
Res
earc
h C
ondu
ctin
g O
ngoi
ng
Res
earc
h P
lans
for F
utur
e R
esea
rch
Inte
rest
in R
esea
rch
by O
ther
Age
ncie
s
No
Cur
rent
Inte
rest
Inte
rest
Ran
king
(1
= n
o in
tere
st,
10 =
hig
h in
tere
st)
SPECIFICATIONS
1. Treatment QC/QA specifications 2. Treatment performance-related specifications (PRS) 3. Warranties for treatments 4. Other(s)?
MATERIALS SELECTION/MIX DESIGN 5. Binder and aggregate tests and procedures 6. Crack and joint sealant material studies 7. In situ pavement property investigations to improve mix/treatment
design
8. Other(s)?
A-3
Question 3: Research Interest (continued) To
pic
ID
Research Area/Topic Con
duct
ed P
ast
Res
earc
h C
ondu
ctin
g O
ngoi
ng
Res
earc
h P
lans
for F
utur
e R
esea
rch
Inte
rest
in R
esea
rch
by O
ther
Age
ncie
s
No
Cur
rent
Inte
rest
Inte
rest
Ran
king
(1
= lo
w in
tere
st,
10
= h
igh
inte
rest
)
TREATMENTS AND STRATEGY SELECTION 9. Characteristics of candidate pavements for preventive maintenance
10. Development/enhancement of treatment selection guidelines 11. Investigation of optimal treatment timing 12. Economic evaluation of treatment effectiveness 13. Other(s)?
CONSTRUCTION 14. Factors that affect treatment performance (surface preparation,
tack coats, weather, and so on)
15. Innovative treatment construction techniques/equipment 16. Innovative field sampling and testing methods for treatments 17. Other(s)?
TREATMENT/PAVEMENT PERFORMANCE 18. Construction and monitoring of treatment test sections. If your
agency is currently constructing/monitoring test sections, please indicate specific treatments in the space provided on the next page.
19. Analysis of historical data to investigate treatment performance 20. Treatment impact on noise, friction, and smoothness 21. Treatment impact on pavement performance (e.g., extension of
service life)
22. Performance measurements/criteria for preservation treatments 23. Other(s)?
OTHERS 24. Training and certification of technicians 25. Integration of preventive maintenance and pavement management 26. Standardization of pavement preservation-related definitions 27. Other(s)?
A-4
In addition to the information provided in the matrix above, use the text box below to provide any additional appropriate information. As a quick reference, please include the corresponding topic ID (number) from the matrix above with each comment included below.
2.0 Pavement Preservation Program Status
This section of the questionnaire explores the current status of your agency’s pavement preservation program. Program Implementation
4. Does you agency currently have a pavement preservation program in place? (Check the one answer that is most representative.) Yes No
Comments:
If you answer “Yes” to question #4, please proceed to question #5. If you answer “No” to question #1, please skip to question #7.
5. Please provided more details about your current pavement preservation program by answering the following questions:
5a. How would you describe your agency’s pavement preservation program? (Check the one answer that is most representative.)
Informal (e.g., Districts or others are following sound pavement preservation practices, but are not doing so under central office direction and do not have dedicated funding).
Formal (e.g., guidelines or policies dictate the program’s practices and dedicated funding is used to pay for treatments).
Formal, but without dedicated funds (e.g., framework has been established, but no funding has been secured to support it).
Comments:
A-5
5b. How long has your pavement preservation program been in place? (Check the one answer that is most representative.)
<1 year 1 to 3 years 3 to 10 years >10 years
If known, in what year did your program become a “stand-alone” program? Comments:
5c. How would you describe the current status of your agency’s pavement preservation program? (Check the one answer that is most representative.)
Well established—A large number of preventive maintenance projects have been constructed and performance has been monitored for a number of years.
Moderately established—Buy-in has been established. A moderate number of preventive maintenance projects have been constructed.
Somewhat established—The pavement preservation program is officially in place, but work continues on buy-in. A small number of preventive maintenance projects have been constructed, with more planned.
Early stages—The program has officially been outlined and put in place, and work continues on establishing buy-in at the SHA management and state legislative levels.
Just beginning—Still in the process of establishing a stand-alone program.
Comments:
5d. How would you describe the current benefits of your pavement preventive maintenance program? (Check the one answer that is most representative.)
Observing reduced costs and improved pavement performance throughout the network.
Some examples of cost savings and/or improved pavement performance have been identified.
It is too early for signs of actual cost savings or improved pavement performance.
A few trial projects are either planned or have been constructed. No data are collected yet.
Work continues on establishing buy-in and overcoming early obstacles.
Comments:
A-6
6. Listed below are benefits/goals frequently associated with successful pavement preservation programs. Please prioritize your benefits/goals (i.e., in the “Ranking of Benefits/Goals” column, assign a “1” to the most important goal, a “2” to the second most important goal, and so on) and check those boxes that apply to your agency.
Benefits/Goals Ranking of
Benefits/Goals Are measures available to track
progress toward this goal? Higher customer satisfaction
Yes No
Better informed decisions Yes No
Improved strategies and techniques Yes No
Improved pavement conditions Yes No
Cost savings Yes No
Increased safety Yes No
Others: Yes No
Comments:
7. If your agency does not currently have a program, is there interest in creating and implementing one? (Check the one answer that is most representative.)
Yes No
Comments:
A-7
Implementation Obstacles
8. Which of the following potential obstacles has your agency faced (or do you expect it to face) during the implementation process? Please indicate the status of each by checking the one answer that is most representative for each potential obstacle. If you indicate that you have faced (or expect to face) a particular obstacle, please indicate the degree of difficulty in overcoming the obstacle by entering a value on a 1 to 10 scale in the last column of the table. Note that a “10” indicates an obstacle that was very difficult to overcome and a “1” indicates an obstacle that was very easy to overcome.
Potential Obstacles Effe
ctiv
ely
Ove
rcam
e C
urre
ntly
B
attli
ng
Fore
seen
O
bsta
cle
Not
Con
side
red
an O
bsta
cle
Diff
icul
ty R
atin
g
(1 =
ver
y ea
sy,
10
= v
ery
diffi
cult)
Identifying a champion for the pavement preservation program—Without a champion to promote the importance and benefits, the effort will fail.
Dealing with the shift away from worst-first project selection—One of the largest obstacles is convincing agency personnel to move away from the worst-first approach and toward treating pavements in good condition..
Gaining commitment from top management—Top management’s commitment includes providing dedicated funding and resources needed to collect information on the effectiveness of pavement preservation, including preventive maintenance treatments.
Showing early benefits—It is important to present early evidence that preventive maintenance treatments have a positive effect on extending service life or reducing life-cycle costs.
Overcoming treatment failures—Failures can result if the correct treatment is not used. For a new program, a single failure can overshadow hundreds of successes.
Competition between the different industries active in providing materials and contracting for maintenance and rehabilitation treatments—With the shift from traditional rehabilitation activities to preventive preservation activities, resistance can be expected from the suppliers and contractors associated with the traditional rehabilitation materials.
Competition between various suppliers of maintenance treatments—When markets have been established for certain types of treatments and a new treatment type is introduced, industry may attempt to block the new products to avoid losing market share.
Political lobbying to prevent the use of new maintenance treatments— In some cases, industry groups may rely on political lobbying to prevent new technologies from entering the market.
Public perception—Initially, the public may not accept the move away from the traditional worst-first approach.
Other(s):
A-8
9. If your agency currently has (or is developing) a pavement preservation program, please describe the five most significant obstacles faced (or that you expect to face) while developing the program. That is, what are the five most important obstacles to overcome in order to achieve a successful pavement preservation program? Where appropriate, please include a brief description of the actions undertaken to overcome these obstacles, and provide a copy of any applicable written policies/documentation if possible.
Obstacle 1:
Action(s) taken:
Obstacle 2:
Action(s) taken:
Obstacle 3:
Action(s) taken:
Obstacle 4:
Action(s) taken:
Obstacle 5:
Action(s) taken:
10. What advice would you give other agencies to help them avoid some of the implementation pitfalls that you have experienced?
A-9
Pavement Preventive Maintenance Program Funding
11. Does your agency have a dedicated budget for a pavement preservation program? (Check the one answer that is most representative.) Yes No
If “Yes,” then:
What level of annual funding is dedicated for 2004? (Provide amount: $ or select the one answer below that is most representative.)
<$10 mil $10 to $25 mil $25 to $50 mil $50 to $75 mil >$75 mil
Comments:
12. If a dedicated funding source is available, how would you characterize the administration and distribution of pavement preservation funds? (Check the one answer that is most representative.)
Centralized De-centralized Combination
Comments:
3.0 Selecting Pavements for Preventive Maintenance
13. On what facility types does your agency currently apply preventive maintenance treatments? (Check all that apply in the two columns on the right).
Roadway Setting Roadway
Classification
General ADT Range Associated with Different Roadway Classifications
(vehicles per day [vpd]) Rural Urban
Freeway 30,000 and above
Arterial 12,000 to 40,000
Collector Road 2,000 to 12,000
Local Road <= 2,000
Comments:
A-10
14. Approximately what percent of your preventive maintenance projects are placed on pavements in each of the following condition categories?
Pavement Condition Percent of PM Projects Applied on
Pavements at a Given Condition Level
Very Good
Good
Fair
Poor
Very Poor
Total 100%
Comments:
15. Does your agency typically apply more than one preventive maintenance treatment before rehabilitation? Check the one answer that is most representative. If you answer “Yes,” please explain.
Yes No
Comments:
16. For what purposes do you apply preventive maintenance treatments? (Check all that apply).
Seal surface
Reduce water infiltration
Increase friction
Increase smoothness
Reduce rate of deterioration
Lane delineation
Noise abatement
Other:
Comments:
A-11
4.0 Preventive Maintenance Treatment Selection, Timing, and Performance
Included Treatment Types
17. Which of the following treatments are applied in a preventive manner (i.e., to pavements in good condition)? Check all boxes that apply to indicate the current status of the use of each treatment.
Treatments for Flexible and Composite Pavements
Treatment Type Completed
Projects
Projects In
Progress Planned Projects
Interested in Using
Not Used
Treatments for Hot-Mix Asphalt (HMA)-Surfaced Pavements Saw and seal or rout and seal cracks Overband crack seal Cape seal Fog seal Scrub seal Slurry seal Rejuvenators Single course microsurfacing Multiple course microsurfacing Single course chip seal Multiple course chip seal Chip seals with polymer-modified asphalt binder Paver-placed surface seal (e.g., Novachip) Thin HMA overlay (<40 mm [<1.5 in]) Cold milling and HMA overlay (<40 mm [<1.5 in]) Ultra-thin HMA overlay (<20 mm [<0.75 in]) Hot in-place HMA recycling (<40 mm [<1.5 in]) Cold-in-place recycling Profile milling Ultra-thin whitetopping Underdrain outlet repair and cleaning
Other:
Other:
Treatments for Portland-Cement Concrete Pavements Concrete joint resealing Concrete crack sealing Diamond grinding Diamond grooving Partial-depth concrete pavement repair Full-depth concrete pavement repair Dowel bar retrofit (load-transfer restoration) Thin PCC overlays Underdrain outlet repair and cleaning
Other:
Other:
A-12
Treatment Selection Process
18. Which of these best describe the method your agency uses to select a preventive maintenance treatment for a given pavement? (Check all that apply.)
Preset schedule of times
Use of a selection matrix based on distress types and severities/extents
In-house guidelines
Industry guidelines
Engineering judgment
Cost/benefit analysis
Other:
Comments:
19. Is the selection of pavement preservation activities tied to your agency’s pavement management system? Check the one answer that is most representative. If you answer “Yes,” please explain.
Yes No
Comments:
19a. If you answered “Yes” to question 19, describe the status of the integration of pavement
preservation and pavement management in your agency? (Check the one answer that is most representative.)
Completely integrated
Currently in the process
In-house guidelines
Plans for integration
Interested
No interest
Comments:
A-13
Treatment Timing
20. Which best describes the method your agency uses to time the placement of preventive maintenance treatments? Check the one answer that is most representative. Please provide a brief explanation, if necessary.
Predetermined timetable
Triggered when minimal distress appears
Placed when distress reaches a medium severity level
Other:
Comments:
21. Do you use a pavement management system or maintenance management system data to optimize the timing of preventive maintenance treatments? Check the one answer that is most representative.
Yes No
Comments:
Treatment Performance
22. Does your agency currently track the performance of preventive maintenance treatments performance? (Check the one answer that is most representative.)
Yes No
If “Yes,” then:
Describe your agency’s performance tracking system.
If you do track performance, how often do you conduct surveys (or run reports)?
If “No,” describe any plans to begin to monitor treatment performance.
23. Have you analyzed your treatment data to estimate an expected life of your preventive maintenance
treatments? Check the one answer that is most representative. If “Yes,” please summarize the expected treatment lives below.
Yes No
Comments:
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24. What are some pavement preservation treatment-related success stories that you would like to share with other SHAs?
25. Do you have any pavement preservation treatment-related failures or setbacks that you would like to share with other SHAs?
5.0 Obtaining Quality Treatments
Specifications/Guidelines
26. How would you describe your pavement preventive maintenance treatment specifications? (Check the one answer that is most representative).
Recent [up-to-date] Adequate Need improvement Out of date Non-existent
Please explain, if necessary.
26a. If you have specifications, were they developed in house or modified from industry publications? Please explain.
27. Does your agency have in place quality control/quality assurance (QC/QA) procedures for preventive maintenance applications? (Check the one answer that is most representative.) Yes No
If “Yes,” would you describe these QC/QA procedures as informal or formal?
If “No,” what are your plans for implementing QC/QA procedures?
28. Does your agency use warranty specifications on any of your preventive maintenance treatments? (Check the one answer that is most representative.) Yes No
If “No,” do you have any plans/interest of exploring the use of warranties? Please explain.
A-15
29. Has your agency implemented any performance-related specifications associated with preventive-maintenance treatments? (Check the one answer that is most representative.) Yes No
If “Yes,” for which treatments? Briefly describe your experience with these specifications.
If “No,” do you have plans for implementing performance-related specifications?
Training
30. What is your familiarity with the four pavement preservation courses developed for the National Highway Institute (NHI)? (Check the one answer that is most representative).
Have conducted one or more courses
Plans for conducting one or more courses Aware of courses, but no plans on conducting Not aware of courses, but interested Aware, but not interested
Comments:
31. Has your agency trained personnel on preventive maintenance concepts and/or techniques? Please explain.
32. Does your agency have a technician certification program that includes preventive maintenance treatments?
33. What additional training needs have been identified that are not currently being met within your agency?
A-16