plant mix overview mdt training conference billings, montana march 1 & 2, 2006 presented by:...

Plant Mix Overview

MDT Training ConferenceBillings, Montana

March 1 & 2, 2006Presented By:

Matt Strizich and Danny Hood

Recent Plant Mix Use

0

5

10

15

20

25

30

35

40

Grade B Grade D Grade S

20022003200420052006

Volumetrics Incentives

• 1.45 million or 2.85% in 2005

• 0.48 million or 3.16% so far in 2006

• Percentage of total spent on PMS that year

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Incentives

20052006

Ride Specification Incentives• 0.39% in 2002• 1.51% in 2003• 0.9% +/- from

2004-2006• Percentage of

total spent on PMS that year

00.050.1

0.150.2

0.250.3

0.350.4

0.450.5

Ride Spec

20022003200420052006

Compaction Statistics

-100

-50

0

50

100

150

200

250

300

350

2003 2004 2005 2006

Thousands

Compaction Issues

• Compaction incentives were 1.04% in 2003 and 1.20% in 2004

• Dropped to 0.34% in 2005• Have a net disincentive of

0.22% so far in 2006

Quick Notes

• Volumetrics and the Ride Specification are not included on all projects

• All end-result specifications

Contractors are Earning it!

• MDT is paying 3-5% of PMS costs in incentives

• Plant production has been slowed

• Seeing quality compete with production

Purpose

• Present potential future changes

• Provide reasoning behind changes

• Share information from last year

• Provide the opportunity to ask questions

Topics

• Grade S & Grade D Commercial Specification Revisions

• New ½” Grade S Policy• Ride Specification Revisions• Compaction Issues in 2005• Aggregate Surface Treatment

Experiment

MDT Staff

• Construction Reviewers

• Project Staff• Internal Audit

Contractors

• Montana Contractors Association (MCA)

• Non-Uniformity Complaints

• Claims

Specification Change Process• All specification revisions go

through the Specification Section

• Dan Smith and Ryan Antonovich

• Defined process• Standards Committee coming

soon

Change Process

• Ensures thorough review

• Reviewed by MDT staff and contractors

Plant Mix Specifications

Grade S and Grade D Commercial

Grades of Plant Mix

• Grade S – Volumetrics– Non-

Volumetrics

• Grade D Commercial– Tested– Non-Tested

Why two versions?

• Contract administration• Quality of the same grades of

mix should be equal.• Testing and frequency of

testing varies

Grade S

• Completely revised mix

• Grade S has been successful

• Moved to gyratory compactors

• Bob Weber and Scott Barnes deserve the credit

Volumetrics

• Volumetrics is how MDT administers and controls the plant mix quality

• True end result specification– Successfully encourages

contracts to control their operations

– Want quality to be able to compete with production

Grade D Commercial

• Relatively new specification

• Always used on “smaller projects”

• Bill Fogarty leading the committee

Grade B

• Use for bike paths or other features not subject to heavy loading

• Consider using Grade D or S with chip seals instead

Grade C

• No longer needed

• Grade D Commercial should be used instead

Change Process

• Plan to review specifications yearly

• Will continue to see the same issues if they are not identified

• Anyone can initiate change• People doing the work need to

identify the issues– MDT Project staff– Contractors– Reviewers

Grade S Changes

• Changes are minimal

• Changes are the same for volumetrics and non-volumetrics versions

Mix Designs

• 50 Gyration mixes have been eliminated

• SHRP recommendation for low volume roads

• Created issues with meeting Hamburg testing requirements

Release Agents – Specification• a) Trucks. Remove trucks

from service that leak fluids. When directed, cover each load with canvas or other approved material to protect the mix at Contractor expense. Do not use Diesel fuel as a truck bed release agent. Use a commercially manufactured release agent approved by the Project Manager.

Release Agents - Specification

– b) Rollers. Furnish and use rollers that compact the plant mix to the specified density. Remove rollers that crush the paving aggregates or otherwise damage the plant mix and replace the damaged plant mix at contractor expense.

• Cleaning Agents. Do not use diesel fuel as a cleaning agent or as a release agent for any paving equipment or operations. Use a commercially manufactured release agent approved by the Project Manager.

Release Agents - Justification• Expands the existing

restriction on diesel fuel to all equipment

• Need to be uniform in our enforcement.– Contractors will include

additional cost in bids– Will eliminate having the issue

every time paving starts

Release Agents - Justification• Plant Mix

quality• Employee

safety• Environmental

concerns

Tack

• The cost of SS-1 will be incidental to the cost of Plant Mix Surfacing

• Includes tack between lifts of paving and for sealing rumble strips

• Tack is still required in all instances it was previously used

Tack

• SS-1 will still be a pay item for some uses– Aggregate

surface treatment– Fog sealing

• Reasons for change– The number of

lifts is no longer specified

– Low cost item

Grade D Commercial

• Mostly Clarifications• Extensive revisions last year

– Previously relied only on compaction to control

– Not enough control so 5% penalties on specified properties was added

Grade D Commercial

• Wording change• Material. Provide Grade D

Commercial Plant Mix Bituminous Surfacing with the specified asphalt binder, 1.4% hydrated lime, and meeting Table 701-15A requirements. Use fillers or additives as necessary.

Grade D Commercial

• Clarification• c) Sampling. Sample the

PGAB meeting subsection 402.03.2 (B). A sample is two one-pint (two 500 ml) containers of PGAB. Sample fillers, hydrated lime, additives, aggregate treatment and tack in accordance with MT-601.

Grade D Commercial

• Revised target air voids

• Percent Air Voids:changed from 3-5 to 2-4

• Do not want drier mixes

• Cost of oil is included in the Grade D Commercial bid item

Grade D Commercial

• Reweighing of vehicles is no longer mandatory

• It should still be done in most cases

• The Project Manager may randomly designate the re-weighing of loaded vehicles.

Grade D Commercial

• Reduced the “F” factor from 12 to 6

• a) Acceptance. Rescind Subsection 401.03.12 (E) and replace with the following:Plant mix surfacing is evaluated for density on a lot-by-lot basis under Subsection105.03.2, except as noted in Subsection 401.03.12(B). Change the “F” factor for the Compaction element in Table 105-2 Table of Price Reduction Factors from 12 to 6 for plant mix furnished under this provision.

“F” Factor Change

• Compaction is no longer the only measure for controlling quality

• Want to be consistent with other mixes

• Inflated prices due to haul• Too much risk for Contractors

Grade D Commercial

• Wording clarification• A 5 percent price reduction (15%

maximum), in the unit bid price for PMS Grade D Commercial will be applied for each test not meeting the Mix Design Stability, Flow, Percent Air Voids, Asphalt Binder Properties, Gradation, or Asphalt content specified. Price reductions will be assessed on the quantity of material represented by each failing sample. The quantity of material represented by each sample is the total tons of material produced divided by the total number of samples representing the material.

Grade D Commercial

• The quantity of material represented by each sample is the total tons of material produced divided by the total number of samples representing the material.

• Changed to help keep administration uniform

• Fairer to the contractor

Grade D Commercial – Non Tested• Many of the same changes as

the tested version• Price reductions are only

assessed for obviously defective material

• Added the following: Provide the Project Manager density testing results upon request.

Contract Administration – Tied Projects

• Issue has been identified

• Materials working with construction to develop guidance

½” Grade S Policy

Why?

• Compaction Concerns

• Reduced lift thicknesses

• Lower overall cost

October 2003 Policy

• ½” Required for all lifts less than 60 mm

• Introduced in response to Grade S compaction concerns

• Followed SHRP recommendations

Revised Policy – April 2005

• Limited use of ½” Grade S to low volume roads

• Reduced the overall use.

January 2006 Revision

• Construction Memo• Requires the use of ¾” PMS

whenever 0.15 ft or greater is required

• Requires ½” Grade S only be used for overlays

• Allows reduced overlay depths if ½” is used

Additional Requirements

• ½” Grade S can only be used if:– Ave. Rut =

0.20 inches or less

– Ave Ride = 80 in/mile or less

– An isolation lift is required

– Surfacing Design must approve

Implementation

• Surfacing Design will review existing design projects and make recommendations

• Projects will not be changed from ¾” to ½” Grade S

• Change orders will be considered – Should not be “no cost”

½” Facts

• ½” Gr. S is more difficult to compact

• ½” Gr. S is more expensive

• ½” Gr. S is equal to or better than ¾” structurally

Ride Specification Revisions

Meeting Agenda

• Introduction

• Project Background

• Draft Revised Ride Specification

• Discussion of Pay Adjustment Factors

Project Purpose

• Review Current Specification

• Compare with Current Literature

• Compare with State-of-Practice

• End Products

Why Is Pavement Roughness Important?

• Ride Quality• Impacts on Vehicle

Maintenance


•User Cost

– WesTrack Experiment

4.5% Increase in Fuel Efficiency

Savings of 10,257 gal of fuel

per 1,000,000 veh miles

Approx. 10% Drop in IRI

$

Project Background• Montana Residents Survey in

1998– Attention & resources in the

following order: • Winter maintenance

• Surface smoothnessSurface smoothness• Highway striping, debris removal,

highway signage, winter roadway information, roadway maintenance, rest stop maintenance

• Etc.

Revised Documents

• Profiler Operations Manual (POM)– Comprehensive

• MT-422 Document– Summary of POM

• QC/QA Plan– Emphasis on field activities

• Draft Revised Ride Specification

Profiler Operations Manual (POM)

• Calibration of Equipment

1. Full Calibration Check of Laser Sensors

2. Calibration of Accelerometers

3. Bounce Test Profiling System

4. Calibration of DMI

Full Calibration Check of Laser Sensors

•Calibrated and sealed by Manufacturer

Courtesy Testing

• At least 7 calendar day notice to EPM

• MDT will provide once per project– Not less than 2 and not more

than 3 miles of continuous pavement

• Contractor interprets results

Surface Smoothness

• All mainline travel lanes including climbing lanes, passing lanes and ramps that are 0.2 miles or longer

• Bridge decks included only if paved as part of project

Surface Smoothness

• Not evaluated

– Climbing and passing lanes less

than 0.2 miles

– Turning lanes

– Acceleration and deceleration

lanes

– Shoulders and gore areas

– Road approaches

Surface Smoothness

• Not evaluated

– Horizontal curves 900 feet or

less in centerline radius

– Pavement within 50 feet of

bridge decks (only for bridges

not paved as part of project)

– Pavement within 50 feet of

approach slabs and terminal

paving points of project

Profiling Test Section• Procedures• Minimum of Two Runs

Start of Data Collection

With F3 Key

End of Data CollectionWith F3 Key

Beginning of Project (BOP)

End of Project (EOP)Exclude

Area (e.g., Bridge)With F5 Key

Approx. 500 ft.Approx. 500 ft.

Quality Control Report

Acceptability: – For each interval, the average

IRI for each run is within ± 5.7% of the mean IRI for both runs

– If a run has an interval that is outside the acceptable limit, additional runs (up to three) should be made on that lane

Quality Control Report

Interval Run 1 Run 2 MeanAvg

-5.7%Avg

+5.7%

Does Run 1 Meet

Criteria?

Does Run 2 Meet

Criteria?

1 67 67 67 63 71 okay okay

2 72 72 72 68 76 okay okay

3 68 67 68 64 71 okay okay

4 57 57 57 54 60 okay okay

5 67 66 67 63 70 okay okay

6 61 62 62 58 65 okay okay

7 59 60 60 56 63 okay okay

Meets Criteria So Use Run 1…for Roughness Report

Surface Profile

• Correct surface profile defects that fail bump criteria

– 0.40 inches in a distance of 25 feet

• Correct surface profile defects– Milling and filling– Diamond grinding

Bump Report

• Considered Other Methodologies– Profilograph Simulation,

– Bumpfinder and Grinding Simulation

– Localized Roughness (TEX-1001-S) Method

• Current System is Satisfactory

Bump Report

• Bump Report for only first error free profile run in each lane is presented to EPM

• Defect locations should be physically verified

File Naming Convention

• 7 Characters– 1 to 4 is Control Number– 5 to 6 is Direction– 7 is Lane

• Example

1022NBT: Control Number 1022, northbound direction, travel lane1022NBT: Control Number 1022, northbound direction, travel lane

File Directory

• Two Conventions– By Control Number– By Date

D:\1022

D:\15JUL05

D:\1022

D:\15JUL05

Current Ride SpecificationClas

s Target (in/mi)

Other Criteria

I 46-653 or more opportunities

Pre-Pave IRI < 140 in/mi2 Opportunities

Pre-Pave IRI <90 in/miSingle Lift Overlay

II 55-75

Pre-Pave IRI 140 in/mi2 Opportunities

Pre-Pave IRI >90 in/mi and <140 in/miSingle Opportunity

III 56-80

Pre-Pave IRI 140 in/mi and <190 in/miSingle Opportunity

IV 61-90Pre-Pave IRI >190 in/mi Single Opportunity

Data Set

Class Coun

t

Post-Pave IRI Avg (in/mi)

Min IRI (in/mi)

Maxi IRI

(in/mi)

Std Dev

(in/mi)

I 63 50 38 66 7

II 13 51 44 58 4

III 2 46 45 47 1

IV 2 61 59 63 3

40

50

60

70

80

90

100

40 50 60 70 80 90 100Post-Pave IRI (in/mi)

Post

-Pav

e IR

I (in

/mi)

Avg MDT Class I

Avg MDT Class II

Avg MDT Class III

Avg MDT Class IV

Class I Target

Class II Target

Class III Target

Class IV Target

Category 1

• Target IRI set at 50 to 55 in/mi

• Project with two or more opportunities to improve the ride

• Single lift overlays with pre-pave IRI < 110 in/mile

• Maximum post-pave IRI should not be greater than 90 in/mi

Category 2

• Target IRI set at 55 to 60 in/mi

• Single lift overlays with pre-pave IRI value 110 in/mi and < 190 in/mi

• Maximum post-pave IRI should not be greater than 95 in/mi

High Pre-Pave IRI Roadways

• Exception for roadways with pre-pave IRI >190 in/mi

– Treat as Category 1• 2 or more opportunities

– Other• Budget, functionality, etc.

• Specify a maximum post-pave IRI NOT be more than 50% of pre-pave IRI

Opportunities• Placing a gravel base or surfacing

course• Placing plant mix bituminous base• Placing cement treated base• Placing pulverized plant mix

surfacing• Milling• Cold recycling (milling and

laydown)• Each full 0.15 ft increment of new

plant mix surfacing

Data Set

Class Coun

t


Min IRI (in/mi)

Maxi IRI

(in/mi)

Std Dev

(in/mi)

I 63 50 38 66 7

II 13 51 44 58 4

III 2 46 45 47 1

IV 2 61 59 63 3

Category

Count


Min IRI (in/mi)

Maxi IRI

(in/mi)

Std Dev

(in/mi)

1 73 51 38 66 7

2 7 51 47 58 5

40

50

60

70

80

90

100

40 50 60 70 80 90 100Post-Pave IRI (in/mi)

Post

-Pav

e IR

I (in

/mi)

Class I Target

Class II Target

Class III Target

Class IV Target

Category 1 Target

Category 2 Target

Avg MDT Class I

Avg MDT Class II

Avg MDT Class III

Avg MDT Class IV

40

45

50

55

60

65

40 45 50 55 60 65Post-Pave IRI (in/mi)

Post

-Pav

e IR

I (in

/mi)

Avg Category 1

Avg Category 2

Category 1 Target

Category 2 Target

Current Pay Adjustment Factor

Class Actual IRI

(in/mi)Pay Factor

I

<40 1.25

40-45 1.10

46-65 1.00

>65 0.80

II

<45 1.25

45-55 1.10

56-75 1.00

>75 0.80

III

<56 1.10

56-80 1.00

>80 0.90

IV

<61 1.10

61-90 1.00

>90 0.90

Pay Adjustment Factor Category 1

IRI (in/mi) Pay Adjustment Factor

< 35 1.25

35 - 50 1.845 – 17/1000 * IRI

50 < IRI <55 1.00

55 - 75 1.825 – 3/200 * IRI

75 < IRI <90 0.70

> 90Corrective Action Required(Initially Assumed as a Zero

Pay)

Pay Adjustment Factor Category 2

IRI (in/mi) Pay Adjustment Factor

< 50 1.10

50 - 55 2.100 – 1/50 * IRI

55 < IRI <60 1.00

60 - 95 1.343 – 1/175 * IRI

> 95Corrective Action Required(Initially Assumed as a Zero

Pay)

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

1.25

1.30

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

IRI (in/mi)

Pay

Adj

ustm

ent F

acto

r

Category 1

Category 2

MDT Class I

MDT Class II

MDT Class III

MDT Class IV

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

1.25

1.30

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

IRI (in/mi)

Pay

Adj

ustm

ent F

acto

r

Category 1

Category 2

Testing & Acceptance

• Prior to seal and cover• Performed with 3 working

days of completion• Contractor must ensure

entire finished lane width can be tested and not impeded

• Test results within 2 working days

Economic Comparison

• Compared current classificationclassification pay versus categorycategory pay

• Evaluated a total of 53 lanes– Category 1 would have 47

lanes

– Category 2 would have 6 lanes

Total for Category 1

$(30,000)

$(20,000)

$(10,000)

$-

$10,000

$20,000

$30,000

$40,000

$50,000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

Current

New Category 1

D

Total for Category 2

$(6,000)

$(4,000)

$(2,000)

$-

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

1 2 3 4 5 6

Current

New Category 2

D

Total Difference

CategoryCurren

t System

New System

D% of

Current System

1 $307,684

$179,083$(128,601

)58%

2 $43,120 $22,389 $(20,731) 52%

Incentive for Category 1

$(20,000)

$(10,000)

$-

$10,000

$20,000

$30,000

$40,000

$50,000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

CurrentNew Category 1D

Incentive for Category 2

$(6,000)

$(4,000)

$(2,000)

$-

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

1 2 3 4 5 6


Incentive Difference

CategoryCurren

t System

New System

D% of

Current System

1 $362,072

$301,494 $(60,578) 83%

2 $43,120 $22,389 $(20,731) 52%

Disincentive for Category 1

$(25,000)

$(20,000)

$(15,000)

$(10,000)

$(5,000)

$-

$5,000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


Disincentive Difference

CategoryCurren

t System

New System

D% of

Current System

1 $(54,388)

$(122,411)

$(68,022) 225%

2 - - - -

Economic Impact Example

Control Numbe

r

Direction

Current Class

Current Pay ($)

Category

New Pay ($)

Post-Pave IRI (in/mi)

2945

EB I $ 8,407 1 $

9,393 43

WB I $ 6,409 1$

6,527 45

4821

NB II $ 8,096 2$

4,226 47

SB II $ 7,569 2$

3,482 47

Economic Comparison

•Incentive–Payment will be similar to current system

•Disincentive–Penalty will be more rigorous than current system


• Ride Quality• Impacts on Vehicle

Maintenance• User Cost• Montana Residents • FHWA Performance Goals• National Trends

Concluding Remarks

• Held a seminar for contractors

• Complete Final Report– Address Comments

• Finalize MDT Ride Specification Document

• First training session – Spring 2006

• Implementation – June 2006

QuestionsQuestions

Draft Revised Ride SpecificationDraft Revised Ride Specification

Compaction Issues – 2005

What’s the problem?

• Extensive problems encountered during 2005

• Did not appear to be one specific problem

• Conditions varied between jobs

Glendive Area Projects

Potential Contributing Factors• Binder problems• ½” PMS• Aggregate Surface Treatment• Aggregate Surfacing• Weather• Contractor Operations

Questions?

Compaction Issues – 2005

Aggregate Surface Treatment

Proposed Experimental Project

What’s wrong with MC-70

• High Volatile Organic Compounds or VOC’s

• Past “prime” failures

Purpose of Surface Treatment • Dust abatement• Surface preservation • Seal• Plant mix compaction aid

Current Practice

• Magnesium Chloride

• SS-1 or CSS-1

Advantages

• Relatively inexpensive• Effective for dust abatement• Helps preserve the section in

most cases• Assists with compaction in

most cases

Disadvantages

• Affinity for water• Needs “fines” and PI in the

gravel for optimum performance

• Corrosion concerns

New Specification

• Currently working on writing

• Intend to allow more flexibility

• Possibly allow alternate products

Experimental Project(s)

• Trying alternate emulsified asphalt products

• Pugmilling SS-1 into the top lift of aggregate surfacing

• Control sections

Objectives

• Try on 2 or 3 projects early in the season

• Evaluate the constructability immediately

• If successful, implement as soon as possible

Questions?

Aggregate Surface Treatments