pavement deterioration modeling in india
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8/18/2019 Pavement Deterioration Modeling in India
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Pavement Deterioration Modeling in India
V. K. Sood, B. M Sharma,
1 .
K. Kanch an, and K. Sitaramanjaneyulu,
Central Road Research Institute India
The large and ever-increasing investment demands for the
upkeep a nd for en suring the desired level of serviceability of
roa d infrastruc ture facilities that w ere created at great cost have
concerned administrators, policy makers, and highway pro-
fessionals in India, and caused them to seek appro priate
solutions, in view of resource constraints, for road maintenance
and reh abilitation prob lems. The development of a pave-
ment management system f or d ifferent conditions prevailing
in the country is a step in this direction.
A
number of studies
have been com pleted for achieving this objective, and a long-
range project entitled the Pavement Perform ance Study (PPS)
is in progress; its goal is to develop data for a total trans-
portation cost model for Indian conditions. The part o f the
PPS
project on Existing Pavement Sections was completed
recently, and pavement deterioration models have been de-
veloped. Separate models are available for estimation of dif-
feren t modes of distress for different types of surfaces. The study
plans and the models developed under the study are pre-
sented, their limitations are described, and future w ork plans
are discussed. The influence of pavement structure, traffic,
and environm ental factors on the progression of cracks and
roughness is illustrated.
A
efficient and adequate transportation system is
one of the key indicators of a nation's prosperity,
its developmental status, and overall economic
growth. India, being the second most populous and the
tenth-largest industrialized country in the world, has an
extensive road transportation system. The roads pass
through areas with extreme climatic conditions-from
heavy rainfall to desert conditions; diverse terrains-
from plains to extremely high m ountain peaks; a nd vary-
ing soil subgrades-rocky and gravelly to marshy land.
Over the p ast four decades, the share
of
total rail and road
traffic carrying passengers and goods has gradually in-
creased from about
24
percent and
11
percent, respec-
tively, in 19 51 to abo ut 8 0 percent and 58 percent,
respectively, in 1990. Road length has increased corre-
spondingly, from 0.4 million km in 1 95 1 o
2
million km,
giving a ro ad den sity of 5 9 kmilOO km'. Because of fast
and ever-increasing industrial, commercial, and other
socioeconomic development activities, the road trans port
vehicle ~ op ul at io n, articularly vehicles carrying goods,
has also increased phenom enally durin g this period.
Efforts are under way in India to develop rational
pavement design procedures that are based on mechanis-
tic principles (critical strain criteria) to replace current
pavem ent design methods, such as the California bearing
ratio (CBR), which are based on an empirical app roach.
Con struction in stages is currently in vogue because of the
paucity of resources. M anu al construction m ethods, used
for many years, are gradually being replaced by mecha-
nized methods, especially for the arterial road network
and high-density corridors. The engineer's judgment and
experience are relied up on heavily in decision making for
maintenance an d rehabilitation
(M R)
of the road netw ork.
Ad hoc M R nor ms are established for assessing mainte-
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation
agencies,
researchers
in
academic
institutions,
and
other
members
of
the
transportation
research
community.
The
information
in
this
paper
was
taken
directly
from
the
submission
of
the
author(s).
8/18/2019 Pavement Deterioration Modeling in India
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48 T H I R D I N T E R N A T I O N A L C O N F E R 1
N C E O N M A N A G I N G P A V E ME N TS
nance budgets; such norms are not hased on scientific or
systematic studies undertaken for the purpose.
Because of economies in road transportation, over-
loading by truck operators is common. The majority of
the arterial roa d system experiences overload ing, as muc h
as 38- to 20-ton ne axle loads versus the permissible legal
limit of 10.2 tonnes. The existing road network has
shown signs of premature distress because of the unex-
pected demands of growing traffic volume and heavier
axle loads. The network has fallen short of its structural
capacity a nd hence it is greatly overstrained . The fun ds al-
located for road development programs have been de-
creasing constantly over the years as a percentage of the
gross national product (GN P). The majority of allocated
funds are utilized for providing M&R measures to the
existing network rather than for new construction. The
funds being provided for the arterial road network are on
the order of 50 to 6 0 percent of the amou nt needed.
On the basis of recent studies, it has been determined
that
3
km of every
5
km
1)
of the arterial road network
(national highways and state highways) is below required
standards and needs upgrading. Th e studies also indicate
th at the country is losing abo ut Rs 60 billion (U.S. 2 hil-
lion) per year i11 additional vehicle operation costs be-
cause of poo r road condition s.
A
Ro ad User Cost Study in
India completed in the early 1 980 s and u pdated recently
has successfully brought out the road user cost models
(vehicle operating costs, accident costs, travel tim e costs,
etc.) under varying traffic, roadway, and climatic condi-
tions. It has been estimated tha t abo ut Rs 60 0 billion (U.S.
20 billion) would be needed up to the year 20 00 for im -
proving and upgrading the national highways (2).
The concept of total transportation cosdlife-cycle cost
and the ap plication of pavement managem ent techniques
have been recognized in India recently as versatile tools
for tackling road maintenance and rehabilitation prob-
lems to achieve efficient and effective utilization of mea -
gre available resources. Some studies have already been
completed an d others are in progress. The results are be-
ing used for developing a suitable pavement maintenance
managem ent system for Indian conditions
3).
Pavement performance data are required fo r the devel-
opm ent of appropriate pavement deterioration models. A
num ber of studies have been conducted to achieve this ob-
jective. Most of the studies, such as the AASHO Road
Test, and the Kenya and Brazil studies, were completed
for local conditions. The World Bank model, HDM-I11
4),
was developed on the basis of data from studies on
Kenya, Brazil, a nd the Caribbean. It is currently finding
global app lication after being calibrated for local condition s.
Some studies were also conducted in India recently. Dur
ing the mid-1980s, the Central Road Research Institut
completed a short-term study on development of riding
quality models for purposes of maintenance accounta
bility 5).But the analysis was hased on two series o
observations and because there was no in-depth charac
terization of materials in the laboratory, the prediction
were useful only as a rough tool f or planning . Th e Universi
of Roorkee developed models for predicting th e life of a
overlay ( 6) .These models are hased on performance dat
from overlaid flexible pavements for the period 19 80 t
1990. The models indicate that there is an exponentia
variation of characteristic deflection, rut depth, crac
length, and maintenance cost with time. In addition t o th
models for individu al distress modes a nd soil types, a gen
eral model was also developed for considering the data fo
all of th e test sections; it predic ts the life of ov erlays of di
ferent materials and thicknesses.
Because of a lack of adequate data to generate com
prehensive deterioration models and to cover
a
variety o
parameters, a long-term study sponsored by the India
Ministry of Surface Transpo rt was initiated in 1 985 . Th
details of the study and the models developed are de
scribed in this paper.
Broad bjectives
The Pavement Performance Study, a sequel t o the already
completed R oad User Cost Study, wa s undertake n for th
primary purpose of developing data for a total trans
portation cost model through the following:
1.
Development of pavement performance data fo
pavement m aterials normally used in the country;
2. On the basis of performance data, development o
layer equivalencies, as feasible;
3
Con duc t of limited stud ies of the effect of the m ain
tenance level on pavement performance; a nd
4.
Generation of data on th e construction a nd mainte
nance inputs of different pavements.
The study com prised two parts:
1 The study on Existing Pavement Sections (EPS
conducted on in-service road sections for expeditiou
development of approximate pavement deterioratio
models; and
2. The study o n New Pavement Sections (NPS ), to h
conducted o n specially designed and constructed exper
men tal sections on in-service highways. N PS will provid
more accurate data generation, refinement of models de
veloped under the study on Existing Pavement Section
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation agencies, researchers in academic institutions, and other members of the transportation research community. The information in this paper was
taken
directly
from
the
submission
of
the
author(s).
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and detailed coverage of parameters over a period of
about 10 years. This part of study, still in its initial stage,
is scheduled for completion by the year 2000.
Study on Existing Pavement Sections
A total of 113 test sections, each 500 m long, on the
existing highways were selected for collecting periodic
pavement performance data over a period ranging from
3 to 5 years. The parameters included in the study are as
follows:
1.
Pavement state
Original construction
Overlaid 1 5 years
Overlaid >5 years
2. Traffic
Medium: 0.4 million-0.8 million equivalent stan-
dard axles (MESA)llaneiyear [600 to 1,200 com-
mercial vehicles per day (CVPD)]
High: >1.0 MESMlanelyear (>1,500 CVPD)
3. Climate
Drylsemiarid (rainfall 15 00 mmlyear)
Moist/subhumid (rainfall >SO0 mmlyear)
4. Pavement condition
Good (no distress)
Fairlpoor (>lo% distress)
5. Pavement surfacings
Premix carpet with seal coat
Asphalt concrete
Semidense carpet
6. Maintenance
Deferred level
Normal level
Higher than normal level
Field Investigations and Performance Monitoring
Six series of periodic performance observations, at
6-month intervals, were made on 40 sections, and 10
series of observations were made on 73 sections, for a
total of 113 test sections. The periodic observations and
measurements taken included the following:
Roughness (fifth-wheel hump integrator),
Deflection (Benkelman beam),
Pavement surface distress (actual measurements of
various modes of distress),
Suhgrade moisture content,
Traffic volume (72-hr count),
Axle load survey (annually, random sampling for
72 hr on 35 selected locations),
Transverse profile, and
Lateral placement of vehicles ( two times during the
sixth and tenth series of performance observations on
selected locations).
The data collected from the office records and the field
were computerized and analyzed in three categories.
Static Pavement haracteristics
Static data on pavement characteristics included the cate-
gory of road type, pavement thickness, and composition
of different layers, pavement width, shoulder details.
The pavement strength was expressed as a structural
numher (SN). The strength coefficients assumed for dif-
ferent layers and materials are given in Table 1. The struc-
tural number was improved by including the effect of
subgrade strength, as follows, and termed the modified
structural numher (MSN).
MSN SN + 3.51 log (CBR)
0.85 (log C B R ) ~ 1.43
1)
where CBR is the percentage of in situ CBR at field den-
sity and moisture content.
In some cases, because of inadequate sample size, the
CBR at field conditions could not he determined in the
laboratory, so it was estimated from the following corre-
iation developed by subjecting the available data to re-
gression analysis t values are indicated in parentheses):
CBR -14.004
+
0.345 (+2.36 mm )
+
0.141 (SC)
(4.54) (4.05)
+
0.154 (PI)
+
17.247 (FDD)
(2.37) (2.30)
0.345 (FMC) R2 0.73 (2 )
(2.36)
where
CBR
CBR
at field condition,
+2.36 mm fraction retained on 2.36-mm sieve
( ),
SC sand content
( ),
PI
plasticity index,
FDD field dry density (gmlcc),and
FMC field moisture content
( ).
plot of observed and estimated values is given in
Figure
1.
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation agencies, researchers in academic institutions, and other members of the transportation research community. The information in this paper was
taken
directly
from
the
submission
of
the
author(s).
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T H I R D INTERNATIOKAL CONFERENCE
O N
MANAGING PAVEMENTS
TABLE
Strength Coefficients
-
Layer Coeff~cient
z
a
3 0
Surfacing
o
0.210.18
sphaltic concrete AC) 40mml25mm
Semi-dense carpet SDC) 25mm 0.16
-
Premix carpet PC) 20mm 0.12
Base Course
0.14
ituminous macadam BM)
m
Built-up spray grout BUSG) 0.13
Thin bituminous layer BT) 0.12
Water bound macadam WBM) 0.12
Subbase
Water bound macadam oversized)
WBM-OS) 0.12
Brick soling 0.10 0 5 1 0 1 5
2 0 2 5 3 0 1
Brick ballast 0.10 O b s e r v e d
C B R (
U n s o a k e d
)
Kankar
0.08
FIGURE
Plot between estimated and observed CUR values
Dynamic Pavement Condition
mercial traffic) and axle loads. The damaging effect of v
hicles was expressed by the vehicle damage factor VDF
Dynamic data on pavement condition included periodic
Equivalent standard axles were calculated for each seri
pavement performance data such as roughness mm/km),
from the traffic data and the VDFs. The cumulative stan
characteristic deflection mm) , subgrade moisture con-
dard axles were derived for each series of observation pe
tent ( ), and different forms of pavement distress
riods. A typical
lot
of the VDFs and equivalen
expressed as percentage of area with respect to total pave-
single-axle loads ESALs) as observed on some of the ex
ment surface area.
perimental sites at different periods during the course o
study is given in Figure 2
Traffic Characterization
Data Sorting and Smoothing
Traffic characterization data included the details of traffic
volume time of day, direction, and average daily corn
As is expected from a study of this nature and magnitud
N OT ES -' . T H E F I G U R ES W I T H I N B R A C K E T S
I N D I C A T E E S A L S I O A Y
2 S E R I E S 1 ,2 ,3 R E P R E S E N T T H E
P E R I O D I C S U R V E Y S
S i t e
1
S i t e
2
S i t e 3 S i t e
L
FIGURE
Variation in VDF and ESALS per day on some experimental sites during the
study period.
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation
agencies,
researchers
in
academic
institutions,
and
other
members
of
the
transportation
research
community.
The
information
in
this
paper
was
taken
directly
from
the
submission
of
the
author(s).
8/18/2019 Pavement Deterioration Modeling in India
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a large variation in the performance data was observed.
Some of the data trends were not justifiable. In order to
overcome the large data variation, particularly that in
roughness because of random and systematic errors, the ex-
ercise of sorting and smoothing data was undertaken.
Data that were unconvincing and extremely out of the
population were excluded from the analysis. The plots of
roughness for each section for different series of measure-
ments were examined individually in the light of mainte-
nance input data provided by the field engineers. In the
absence of any supporting data for the improvement in
roughness, the roughness being a monotonically increas-
ing function with time and axle loadings if resurfacing
or rehabilitation is not done), such data were removed,
and the whole observation period was divided into
subperiods.
The loss of excluded data was mitigated by processing
the time-series data to determine the section-specific rate
of roughness progression over time by a log linear regres-
sion of roughness against time. This was done to minimize
the impact of random errors in roughness. The roughness
was estimated by using the following equation for model
development:
log g
a,
a,PAGE
3 )
where
g
is the observed roughness mm km ) and PAGE
is pavement age months).
Model Development
The large amount of data collected was subjected to the
following forms of analysis: graphical, linear or nonlinear
regression, and multivariate linear or nonlinear analysis.
Data reviews were undertaken from time to time, and
trends between different independent parameters, namely,
MSN versus deflection, roughness versus cumulative stan-
dard axles CSALs),distress versus CSAL, pavement age
versus roughness, and so forth, were plotted to examine
the behavior and interactions of different parameters. The
incremental approach, taking the difference between the
two successive observations, was adopted in multivariate
regression analysis as the most logical approach available
for time-series data analysis for the predictions of change
over the preceding value.
The range of parameters covered in the data analysis
for model development is given in Table 2. As seen from
the table, the wide variation in pavement conditions nor-
mally observed in India was covered in the study. The val-
ues in Table
2
are the changes in different parameters
between the two sets of observations included in the data
analysis after the sorting and smoothing of the data.
These changes are over a period ranging from 0 417 to
1 917 years for premix carpet and from 0 333 to 1 333
years for asphalt concrete. The negative changes in some
of the parameters are due to improvements in surface con-
dition resulting from maintenance inputs made from time
to rime during the study period.
Different forms of statistical models were developed
for prediction of pavement deterioration from the data
obtained after the sorting and smoothing techniques. The
general form of models for the prediction of change in
roughness and cracking are as follows:
Change in roughness ficurrent roughness, change
in surface condition, traffic
volume and loading, pave-
ment age, pavement strength,
maintenance inputs)
Change in distress flcurrent surface condition,
traffic volume and loading,
pavement age, pavement
strength, maintenance inputs)
Separate models developed for roughness progression
and crack progression and for asphalt concrete and pre-
mix carpet surfaces are given in Table 3 These models
permit the prediction of change in roughness and crack-
ing over time. Plots of observed and estimated values for
roughness and crack progression for a premix carpet sur-
face are given in Figures 3 and 4
Separate models were developed for two different types of
pavement surfaces normally used in India. The models
were partly validated also with the data available from
some of the experimental sections. It was found that pre-
dictions for pavement deterioration, especially in terms
of roughness, can be made with reasonable accuracy.
Though the experiment provided for the study of the ef-
fect of different levels of maintenance on pavement per-
formance, the same could not be quantified because of a
lack of feedback on maintenance inputs. For the purpose
of these models, it was assumed that the test sections were
provided with routine maintenance only.
The models presented in this paper are based on the typi-
cal traffic, environmental, and pavement conditions on
the malor highways in India. These models will provide use-
ful input for the development of an appropriate pavement
management system for maintenance planning and for
setting priorities. There is still much data available for
other forms of analysis. In view of the limitations of
these models, further work on different aspects of model-
ing is being continued. The inclusion of deflection in the
models as an indicator of pavement strength is under ex-
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation agencies, researchers in academic institutions, and other members of the transportation research community. The information in this paper was
taken
directly
from
the
submission
of
the
author(s).
8/18/2019 Pavement Deterioration Modeling in India
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T BLE Range o Study Parameters
S1. Parameter Range
No. Premix Carpet Asohaltic Concrete
Minimum Maximum Minimum Maximum
1 APHt
0 . 8 3 0 1 . 5 0 0 0 . 7 7 7 1 . 4 0 0
2 ACRt
3 7 . 6 9 0
5 2 . 9 0 0 2 . 5 5 0 1 8 . 7 6 0
3 APWt -
6 . 9 1 0
1 4 . 4 6 0
8 . 6 1 0 5 . 3 5 0
4
ADEPt
3 . 9 0 0 2 . 6 8 0 1 . 0 0 0 2 . 3 8 0
5
Rat
1 5 1 7 8 6
4 3 3 9 9 5
6
ACSAL
0 . 0 0 1 1 1 . 0 8 0
1 . 0 2 9 1 2 . 9 1 0
7 MSN
1 .
ZOO 4 . 4 8 0
3 . 2 5 0 5 . 0 2 4
8
PAGE
0 . 0 8 3
1 1 . 6 7 0 0 . 8 3 3
1 1 . 6 6 7
9 t
0 . 4 1 7 1 . 9 1 7
0 . 3 3 3 1 . 3 3 3
1 0
Rgi
1 3 3 8
6 6 5 1 1 3 3 4
2 8 6 6
11 CRi
0 . 0 0 0
9 0 . 0 0 0
0 . 0 0 0 2 7 . 9 0 0
where
pxt
= change in potholes 2) over a time t Years)
ACRt
=
Change in Cracking
( )
over a time t years)
APWt
= Change in patch work 2 ) over a time t years)
ADEPt = Change in depression 2 ) over a time t years)
ARgt = Change in roughness mm/km) over a time period
t years)
Rei = Initial rouphnasa mm/km)
CR = Initial cracking ( )
PAGE = Pavement age since last renewal/strengthening
years)
t
=
Time interval years)
MSN = Modified structural number
ACSAL change in cumulative standard axles msa)
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation agencies, researchers in academic institutions, and other members of the transportation research community. The information in this paper was
taken
directly
from
the
submission
of
the
author(s).
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5
4 T H I R D I N T E R N A T I O N A L C O N F E R E N C E O N M A X A G I N G P A V E ME N T S
5 0
C R t
3 2 8 5 6
b C S A L M S ~
m
C6li . t
R~ = 3 5
-
LO
-
-
rn
C
.
.x
2
3 0
C
.
0
0
.D
I
.
FOR PRE MIX CARPET )
.
0 10 2 0 30 LO 50
bserved change in cracki ng 1.)
FIGURE 4 Plot between estimated and observed change in cracking.
plorat ion. Analysis is also planned for predict ion of de-
teriorat ion in terms of combined dis t ress by assigning
sui table weight ing factors to different mode s of dis t ress .
Mo re ref ined model s are expected to be avai l ab le f rom the
s tudy on Ne w Pavement Sections which has a l ready been
launched.
ACKNOWLEDGMENTS
This pa per i s publ ished wi th the permiss ion of th e Di rec-
to r o f the Cent ra l Road R esearch Ins ti tu te . Th e au th ors
gra tefu l ly acknowledge the gu idance prov ided by Y. R .
Phull Depu ty Director an d the assis tance rende red by
Devesh Tiwari scientis t bo th of the Inst i tute. Th an ks are
a l so ex tended to o ther s t aff mem bers o f the Ins t i tu te w ho
ma de con tribut ions dur ing different s tages of the project .
REFERENCES
1 Gupta D. P. M.
K.
Bhalla and S. S. Cha krabo rty. Strategy
for Road and Road Transport Development: Emerging
Issues. lou rn al of the Indian Roads C ongress Vol. 51- 3
Nov. 1990 pp. 597-640.
2
Sikka R. P. Growing Crisis of Managing the Trunk Route
System in India. Journal of the Indian Roads Congress
Vol. 53-2 Sept. 1992 pp. 331-358.
3. Sood V.
K.
B. M. Sharma and K. Sitaramanjaneyulu
Pavement Performa nce Study-An Input Toward s Devel
opment of Pavement Management System in India. Proc.
7th REAAA Conference Singapore V ol. 2 June 199 2
pp. 811-819.
4. Paterson W.D.O. R oad Deterioration a nd Maintenance
Effects. World Bank Publication. The Johns Hopkins Uni-
versity Press Ba ltimore and London 1987 .
5 . Report on Development of Ma i~tcm ance
ased
Preliminmy
Pavement Riding Quality Model for
Tmnk
Routes. Centra
Road Research Institute New Delhi India Ju ne 1986.
6
Jain S. S.
A.
K.
Gup ta and Sanjeev Rastogi. Study of Sn
fluencing Param eters for Efficient Maintenan ce M anage-
ment of Flexible Pavements. Journal of the Indian Roads
Congress Vol. 53-1 June 1992 pp. 93-143.
7 Interim Report on Study on E xisting Pavemeltt Sections
Ce ntral Road Research Institute New Delhi Ind ia D ec
1990.
8. Preliminary Report o n Model Development. Study on Ex
isting Pauement Sections. Central Road Research Institute
New Delhi India March 1993.
3rd International Conference on Managing Pavements (1994)
TRB Committee AFD10 on Pavement Management Systems is providing the information contained herein for use by individual practitioners in state and local
transportation agencies, researchers in academic institutions, and other members of the transportation research community. The information in this paper was
taken
directly
from
the
submission
of
the
author(s).