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Improving the Pavement Conditions :

Pavement Condition Assessment methods, Methods for
optimizing the reparation and maintenance cost for roads

D.SANKARA RAO, SE(C)

ABSTRACT
In a developing country highway infrastructure is the backbone for economic
development. Pavements are the assets of any country. A good pavement is the heart of a
highway or an airport. With increase in traffic and loading, pavement deterioration occurs
which needs to be monitored and captured continuously for preparing efficient maintenance
proposals. Hence there is a need to preserve these assets in good condition, by providing
maintenance derived from optimum rational strategies. Pavement evaluation is a key step in
selecting deteriorated roads for maintenance. Pavement condition rating through various
distress identification and measurement is the need of an hour.The purpose of maintenance is
to ensure that the pavements remain serviceable throughout its design life.Maintenance
prolongs their life by reducing the rate of deterioration, thereby safeguarding investments in
repair and rehabilitation, which will lower the cost of operating vehicles by providing a smooth-
running surface, keeps the road open for traffic with least delay,contributes to better transport
services,sustains socialand economic benefits due to improved road.
This paper covers the need of a good pavement, causes of failures of pavement,
methods of pavement condition assessment, measurement of various surface distresses, rating
of condition of pavement by IRC, ASTM and AASHTO. Various defects in Bituminous surfacing
and different types of road maintenance and their relevance to roads maintained by BRO have
been discussed. Important aspect for cost-effective maintenance is the Selection and Timing of
maintenance activities. Preventive Maintenance relatively inexpensive. It preserves the system,
retards future deterioration and improves functional condition. It is most effective when the
pavement is structurally sound and exhibits little or no distress.Highway Development and
Management Tool (HDM-4)- developed by WB is a powerful management software tool for the
analysis, planning, management and appraisal of road maintenance, improvements and
investment decisions. Optimization of cost of maintenance of road has been discussed and
worked out by proposing a 10 mm thick micro surfacing layer on good conditioned road in J&K
by delaying the renewal coat of AC 30 mm for two years.
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1. INTRODUCTION

Pavement is the structure consisting of superimposed layers of selected and processed

materials placed on a subgrade to support the applied loads and distribute
themtosoilfoundation.

Fig 1.1. Typical cross section of a Flexible Pavement.

It provides adequate, smooth, durable and serviceable support for the loads imposed by
trafficat all times in all weather conditions. A good pavement contributes to a large extent to
the quality of a highway or airport.

2. REQUIREMENT OF A GOOD PAVEMENT

Fig 2.1. Damaged Pavement

Pavement in good condition ensures
(i) Increase in riding quality and saving in Vehicle Operation Cost.
(ii) Saving in travel time.
(iii) Reduction in accident rate.
(iv) Less fatigue and discomfort during travel.
(v) Increased mobility of Essential services and Defence forces.
(vi) Reduced suffering and pain of those involved in highway accidents.
(vii) Savings in maintenance cost.
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3. CAUSES OF PAVEMENT FAILURES

Pavements deteriorate over the period of time due to heavy traffic movement and variation
in climatic conditions.
(i) Defects in the quality of materials used.
(ii) Defects in construction method and quality control during construction.
(iii) Inadequate surface and subsurface drainage.
(iv) Increase in traffic volume and magnitude of wheel loads.
(v) Inadequate pavement crust thickness.
(vi) Settlement of foundation of embankment of the fill material.
(vii) Natural and Environmental factors - heavy rainfall, land slides, soil erosion, high
water table, snow fall, frost action.

4. PAVEMENT PERFORMANCE AND ITS EVALUATION

Pavement Performance - It is the ability to serve traffic safely and comfortably over
a period of time.
Pavement evaluation - is a technique of assessing the condition of a pavement, both
structurally and from the point of view of surface characteristics.It is also known as
pavement condition survey and rating of pavement.
Objectives of Evaluation
(i) To assess as to whether and to what extent the pavement fulfils the requirement.
(ii) To plan maintenance and strengthening jobs in time.

5. PAVEMENT CONDITION ASSESSMENT METHODS

A. VISUAL EVALUATION
Visual evaluation is a simple method Distresses (Alligator cracking, Longitudinal and
transverse cracking, Bleeding, Pothole, Patching, Ravelling, Rutting) are visually noted and
recorded.
B. FUNCTIONAL EVALUATION
based on Riding quality (road roughness), Pavement distresses and Skid resistance.
Surface distresses are actually measured in smaller representative stretches.

1. Pavement Condition Rating (PCR)

The IRC: 82-2015 gives guidelines for Practice of Maintenance of Bituminous Road. For a
Highway, the IRC guidelines asks to collect measurement of following pavement
distresses through observations; cracking, ravelling, potholes, shoving, patching,
settlement and rut depth. based on the measured distresses the standard condition is as
below table 5.1
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(i) It provides a measure the present condition of pavement.

(ii) Provides an objective and rational basis for determining maintenance and
repair needs.
(iii)Used to establish the rate of pavement deterioration for early identification of
rehabilitation needs.

Table 5.1: Pavement Distress Rating

Defect(type) Range of Distress

Cracking (%) >10 5 to 10 <5

Ravelling (%) >10 1 to 10 <1
Pothole (%) >1 0.1 to 1 <0.1
Shoving (%) >1 0.1 to 1 <0.1
Patching (%) >10 1 to 10 <1
Settlement & >5 1 to 5 <1
Depression (%)
Rut depth in mm >10 5 to 10 <5
Rating 1 1.1 – 2.0 2.1 – 3.0
Condition Poor Fair Good

After assigning rating to each parameter, an appropriate weightage is given to rating

value of each parameter for calculation of Weighted Rating Value for each parameter.

Table 5.2:Pavement Distress Weightage

S.No Defect(Type) Weightage(fixed)

Multiplier factor

1 Cracking (%) 1.0

2 Ravelling (%) 0.75
3 Pothole (%) 0.50
4 Shoving (%) 1.0
5 Patching (%) 0.75
6 Settlement & 0.75
Depression (%)
7 Rut depth in mm 1.0

The Final Rating Value is calculated by taking the average of the Weighted Rating Values of
all parameters viz. cracking, ravelling, potholes, shoving, patching, settlement and rut depth.
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2. Pavement Condition Index (PCI)

The PCI is a numerical indicator that rates the surface condition of the pavement in the
scale of 0 to 100. This has been developed by ASTM. The PCI provides a measure of the
present condition of the pavement based on the distress observed on the surface of the
pavement, which also indicates the structural integrity and surface operational condition
(localized roughness and safety).

Standard PCI Rating Scale

100 Good
85 Satisfactory
70 Fair
55 Poor
40 Very Poor
25 Serious
10-0 Failed

The ASTM method is a deduct value approach method which considers and the types of
possible distress and its severity parameter. The severity of the distress typeis the most important
index in pavement performance evaluation. The ASTM method is time consuming and requires
accurate measurements and severity identification. The ASTM recommends 19 types of pavement
distresses.

3. Present Serviceability Index (PSI)

This has been developed by AASHTO involving the measurement of permanent

deformation, riding quality and the extent of cracking and patching. PSI is probably the most widely
used pavement rating measure in existence today.
rating 1 represents very poor pavement
rating 5 represents excellent pavement
Flexible Pavements
PSI = 5.03-1.91 log(1+SV)-1.38(RD)² - 0.01√(C+P)
Rigid Pavements
PSI = 5.41-1.80 log(1+SV) - 0.09√(C+P)
SV = Slope variance giving an index of the longitudinal profile.
RD = Rut depth under a 4 ft. strait edge.
C = Amount of cracking(lineal feet of cracks/1000 sq ft. area).
P = Patched area(sq ft/1000 sq ft area).
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C.STRUCTURAL EVALUATION

Measurement of transient deflection of pavement under design wheel loads serve as an

index of the pavement to carry traffic loads under the prevailing conditions. The following tests are
used for assessing theload carrying capacity of the pavement.
i) Static Plate Bearing Test.
ii) Benkelman Beam method.
iii) Falling Weight Deflectometer.
iv) Lacroix Deflectograph.
v) Dynaflect.

6. PAVEMENT CONDITION SURVEY

Condition surveys are carried out before monsoon and after monsoon in case of NHs and after
every monsoon for other roads.Surface condition is assessed in terms of roughness, pavement
surface distresses, skid resistance and texture depth.Based on condition survey and condition
rating, type of maintenance activity will be decided. A plan has to be drawn for preventive
maintenance or periodic renewals based on pavement condition rating.

A. Measurement of Unevenness or Roughness

Unevenness or Roughness can be defined as “deviations of a travelled surface from a true

planar surface with characteristic dimensions that affect riding quality, vehicle dynamics,
dynamic pavement loads and pavement damage”
The methods of measuring roughness can be broadly grouped under two categories:
1. Direct measurement of the longitudinal profile.
2. Response type instrument methods.
It is assessed in terms of Roughness Index in mm/km.
(i) Fifth wheel Bump Integrator.
(ii) Car axle Mounted Integrator.
(iii) Laser Profilometer.

B. Measurement of Pavement Surface Distress

Distress is developed in the pavement in the form of cracking, ravelling,potholes,

edge break, rut depth, patch work, texture with passage of timedue to traffic volume, loads
and climatic conditions.
(i) Manual method.
(ii) Pavement surface imaging technique.
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C. Measurement of Skid Resistance

The following devices are used for measurement of skid resistance.
i) Stopping of test vehicles.
ii) Braking of vehicles with a test wheel.
iii) Portable Skid resistance Tester.
iv) Mu-Meter.

D. Measurement of Texture Depth

i) Sand patch method(for macro texture depth)
ii) Laser based system(for micro texture depth)

7. SERVICEABILITY INDICATORS FOR HIGHWAYS

S.No Serviceability Indicator Level 1(good) Level 2(Fair) Level 3(poor)

1 Roughness(max permissible) 1800 mm/km 2400 mm/km 3200 mm/km

2 Skid Resistance(Skid Number) 60 SN 50 SN 40 SN
Min desirable
Level 1- match with new pavement condition.
Level 2- in service minimum desirable level.
Level 3- warrant for intervention to restore the pavement to level 1.

8. MAINTENANCE OF ROADS
Road Maintenance - Preserving and keeping each type of roadway, roadsides, structures as
nearly as possible in its original condition as constructed or as subsequently improved to provide
satisfactory and safe transportation.
Road maintenance includes
Maintenance of pavement, structures, drains and cross-drainage works, shoulders and
slopes, bridges, road furniture.
The timely upkeep and maintenance of bituminous surfacing offers numerous benefits for
preservation of road asset.
i) Improvement of Riding quality.
ii) Reduction in rate of deterioration and improvement in life of road.
iii) Reduction in Vehicle Operation Costs (VOC).
iv) Reduction in rate of accidents.
v) Keeping roads traffic worthy in all weathers.
vi) Reduction in pollution due to reduced fuel consumption.
vii) Savings in budgetary expenditure of restoration/ reconstruction.

Timely and regular maintenance of roads have been known to provide economic return as
high as 15 to 20% depending upon the category of road and traffic volume.
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9. TYPES OF MAINTENANCE
1. ROUTINE MAINTENANCE
This covers items such as filling of potholesrepairing of cracks and patch work, maintenance
of shoulders and cross slope, up-keep of road side drains,pavement markings which are
undertaken by the maintenance staff almost round the year.
2. PREVENTIVE MAINTENANCE

A planned maintenance activity, which decreases the rate of surface deterioration

and extend service life of bituminous pavement. This provides following longterm solutions.
(i) Improved level of service resulting from improved pavement performance.
(ii) Delayed need for rehabilitation and reconstruction.
(iii) Life cycle cost saving.

Fig 9.1. Timing of Preventive Maintenance.

Preventive Maintenance Treatments are:

(i) Crack sealing/crack filling.

(ii) Fog seal.
(iii) Slurry seal.
(iv) Micro surfacing.
(v) Surface dressing.
(vi) Thin surfacings.
(vii) Ultra thin friction courses.
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3. PERIODIC MAINTENANCE
Periodic maintenance consist of the provision of a surfacing layer at regular
intervals of time or at a specified condition so as to preserve the required serviceability level
of the pavement surface and offset the wear and tear caused by traffic and weathering.
Periodic renewals represent the maintenance , which is needed to prevent deterioration of
the pavement and to ensure that initial qualities are kept up for the future requirements of
the pavement.
It is carried out:
(i) To extend the service life of an existing pavement.
(ii) To improve the load carrying capacity.
(iii) To preserve the required serviceability level of the pavement.
(iv) To offset the wear and tear caused by traffic and weathering.
This includes
Surface dressing ( one or two coats),Thin premix carpet, Mixed seal, Stone matrix
asphalt,Dense bituminous concrete,Micro surfacing (one or two layers).
4. SPECIAL REPAIRS

Special Repairs and strengthening of pavement with overlays are needed to prevent
pavement failures. It includes
(i) Strengthening of pavement structure.
(ii) Reconstruction of pavement.
(iii) Widening of roads.
(iv) Improvement of geometrics.
(v) Repair of damages caused by monsoon/floods.
(vi) Repair of subsurface drainage and cross drainage structures

Fig. 9.1. Pavement Maintenance.

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10. DEFECTS IN BITUMINOUS SURFACING

The types of defects in bituminous surfacing are grouped under four categories as under:

1. SURFACE DEFECTS Bleeding or - Applying heated coarse sand, open

Fatty surfacegraded premix, milling out the affected
portion.
Smooth surface - Resurfacing with premix carpet, surface
dressing or micro surfacing.
Streaking - Application of new surface.
Hungry Surface - Slurry seal or fog seal

2. CRACKS Hair-line cracks - Fog seal, slurry seal, micro surfacing

Alligator cracks - Crack sealing, milling and resurfacing
Longitudinal cracks- Crack sealing, remove and replace
with fresh overlay
Edge cracks - Good drainage along edge of the road,
permeable material on shoulders
Shrinkage cracks - Fog seal, slurry seal, micro surf
Reflection cracks -Fog seal, slurry sealing, application of
liquid rejuvenating agents, use of SAM or
SAMI

3. DEFORMATION Slippage -Removal of affected area and

replacement with fresh material
Rutting- Filling the depressions with premix
material
Corrugations -Scarification and relaying of surfacing, cutting
high spots and filling low spots
Shoving-Removing the material to firm base and
relaying a stable mix.
Shallow depression-Fillingwith premix materials
Settlements -Excavate defective fill and redone,
and upheavalstrengthening.

4. DISINTEGRATION Stripping -Replacement with fresh bituminous

mix added with anti-stripping agent,
slurry seal, micro surfacing.
Ravelling-Slurry seal, micro surfacing,resurfacing.
Pot holes-Filling with cold/hot mixes, ready mixes,
penetration patching.
Edge breaking-Cutting the affected area and
rebuilding
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11. MAINTENANCE COST OF ROADS

The cost of maintenance of roads depends on
(i) Volume and intensity of traffic.
(ii) Cost of materials.
(iii) Labour and machinery.
(iv) Type of terrain.
(v) Type of wearing surface.
(vi) Minimum level of serviceability considered for that category of road.
(vii) Climatic conditions.

12. OPTIMIZATION OF MAINTENANCE COSTS

Important aspect for cost-effective maintenance is the Selection and Timing of
maintenance activities.
Preventive Maintenance relatively inexpensive - Preserves the system, retards future
deterioration and improves functional condition. Most effective when the pavement is
structurally sound and exhibits little or no distress.
Preventive maintenance shall be undertaken before PCR drops to 2.
If the Pavement distress already present- corrective maintenance (pothole repair and
patching, joint replacement or slab replacement) is more appropriate.
Routine maintenance like crack filling may be considered for small distress.
Periodic renewals may be undertaken at a PCR of 2.
Strengthening requirement be assessed if PCR is 1.

13. PAVEMENT MANAGEMENT SYSTEM (PMS)

A tool or method that assists inoptimizing strategies for providing and maintaining
pavements in a serviceable condition over a given period of time.
PMS constitutes the following aspects
(i) Pavement Condition Data.
(ii) Maintenance Standards.
(iii) Economic Analysis.
(iv) Programming.
(v) Control of Works and Feedback.
(vi) Budgetary Analysis.

It helps users select cost-effective alternatives for pavement maintenance and

rehabilitation.
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Highway Development and Management Tool (HDM-4)

A powerful management software tool developed by WB for the analysis, planning,

management and appraisal of road maintenance, improvements and investment
decisions. It is used to
(i) to make comparative cost estimates and economic evaluations of different
construction and maintenance options.
(ii) perform a comprehensive life-cycle analysis of agency costs, user costs, and
benefits using condition deterioration models for roughness, cracking,
ravelling, rutting and edge breaking.

14. COST SAVING IN MAINTENANCE

DATA
Project Area - Jammu & Kashmir (UT)
Name of Road - BG – POONCH (NHDL)
Pavement - in good condition
Length - 40 km
Type of renewal coat - 30 mm AC
Re surf cycle Period - 3 years
Maint& Re Surf rates - 2017-18
Preventive maint to be adopted - Micro surfacing 10 mm thick.
CALCULATIONS
Cost of RoutineMaint as per Scale = 40x4.63 = 185.2 lakhs.
Cost of Resurf 30 mm AC with correction work 50 mm BM - 1604 lakhs.
Cost of Micro surf 10 mm th with 2% cement = 40x7x1000x1.05x200 =588 lakhs (rate of
micro surf Rs 200/sqm).
Assuming the recycle period is differed by 2 years by adopting preventive maintenance of
micro surfacing.
Total Cost of Maint = Routine Maint Cost for 5 y + Preventive Maint cost (Micro surf) =
185.2x5+588x1 = 1514 lakhs.
Total Cost of Maint without Preventive Maint = Routine Maint Cost for 5 Y + Cost of Renewal
coat = 185.2x5+1604 = 2530 lakhs.
Saving in cost of maint in 5 year period = 2530-1514 = 1016 lakhs (40.16% of total maint
cost)
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15. CONCLUSION
1. There is a need to introduce the system of assessing the condition of each road before
planning the maintenance works to be carried out in BRO.
2. In BRO, maintenance of roads is being carried out as Routine Maintenance (drain clearance,
berm filling, patch repair etc),Periodicrenewals(resurfacing) and Special/Emergent
repairs(IRMD, SRMD, Improvement/Rehabilitation of roads).
3. There is no concept of costeffectivePreventive Maintenance (fog seal, slurry seal, micro
surfacing, thin asphalt layers with NMAS of 9.5 mm) in BRO which extend the life of
pavement and reduces the costs of renewal coats and rehabilitation.
4. A certain percentage (about 20%) of Periodic renewal funds may be utilized for Preventive
maintenance with better materials.
5. Condition survey of important roads in each Project should be carried out through
Consultancy Agencies for working out the time and type of preventive treatment to be
applied on each road and to conclude a consolidated Performance Based Maintenance
Contract.
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Resurf works carried out by Self in 2017