i

UNIVERSITY OF NAIROBI

FCE590

EVALUATION OF FLEXIBLE PAVEMENT CONDITION; A CASE STUDY OF ISIOLO-

MERILE RIVER ROAD (A2)

BY:

RICHARD ODHIAMBO OTIENO

F16/38202/2010

Supervisor: Prof. Mbeche O Oyuko

A project submitted as a partial fulfillment for the requirement for the award of the degree

of

BACHELOR OF SCIENCE CIVIL & CONSTRUCTION ENGINEERING

2015

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Abstract:

The purpose of this study was to evaluate condition of a section of IsioloMerile River Road (A2)

which is part of the Northern Corridor. In this report, findings of the pavement condition survey

such as structural adequacy assessments, surface distress survey, pavement roughness and traffic

volume are presented.

Structural adequacy was assessed using Falling Weight Deflectometre (FWD) in the field to

determine strength characteristics of pavement layers.Analysis of the deflection data obtained

using FWD shows that the material properties are within acceptable range and the pavement is

structurally adequate to sustain existing and future traffic loading up to the design life. However,

for the pavement to reach its design life, observed surface surface distress must be addressed.

Surface distress survey was conducted by visual observations and measurements to determine

the severity and density of observed distresses. The dominant surface distresses observed

comprise of longitudinal wheel path cracks, edge cracking, traverse cracking, raveling and

rutting. They have varying severity and density levels at various sections.. The potential causes

of the above surface distresses might be attributed to by inadequate bonding during construction,

insufficient shoulder support, poor compaction and poor adhesion of aggregates due to

insufficient asphalt content. However, the road can be considered as GOOD in terms of surface

condition rating.

Pavements deteriorate over time due to the action of traffic and environmental factors.

Consequently, they must be maintained or rehabilitated regularly to keep them in good condition

and ensure they have structural adequacy to perform throughout their design life.

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Acknowledgement

I want to express my deep gratitude to my supervisor, Prof.Mbeche for his guidance throughout

this study. He provided me with all the knowledge, experience and support that I needed to

accomplish this report. It was a great pleasure for me to have him as my supervisor. His help and

support are really appreciated.

I am also grateful for Mr. Ogalo, (chief technologist materials Laboratory, University of Nairobi)

for the help and support he provided during my study.

I am very indebted to my mentor Eng. Samuel Ogege for his moral and financial support and

advice to date.

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TABLE OF CONTENTS

Abstract: ........................................................................................................................................................ ii

Acknowledgement ....................................................................................................................................... iii

List of Acronyms ........................................................................................................................................... vi

List of tables ................................................................................................................................................ vii

List of figures .............................................................................................................................................. viii

CHAPTER ONE ............................................................................................................................................... 1

1.0 Introduction ............................................................................................................................................ 1

1.1General ................................................................................................................................................ 1

1.2 Study Area ......................................................................................................................................... 1

1.3 Problem Statement ............................................................................................................................ 2

1.4 Objectives........................................................................................................................................... 3

1.5 Scope of study .................................................................................................................................... 3

1.6 Limitations of the study. ................................................................................................................... 3

CHAPTER TWO .............................................................................................................................................. 4

2.0Literature review ...................................................................................................................................... 4

2.1 General Introduction ........................................................................................................................ 4

2.2Functional Evaluation. ...................................................................................................................... 4

2.2.1Roughness. ................................................................................................................................... 4

2.2.2Distress Evaluation ..................................................................................................................... 9

2.3Structural Capacity Evaluation. ..................................................................................................... 19

2.3.1 Static / Creep Loading Equipment ......................................................................................... 19

2.3.2Dynamic Loading Equipment .................................................................................................. 20

2.3.3Backcalculation of pavement layer moduli ............................................................................. 24

2.3.4Effect of temperature on bituminous layer ............................................................................. 27

2.4Traffic Loading Effect ..................................................................................................................... 27

CHAPTER THREE .......................................................................................................................................... 30

3.0Methodology .......................................................................................................................................... 30

3.1Functional Evaluation Methodology .............................................................................................. 30

3.1.1Distress Condition Survey ........................................................................................................ 30

3.1.2Roughness field test ................................................................................................................... 30

3.3Structural Evaluation Methodology ............................................................................................... 31

3.3.1Traffic count Methodology ....................................................................................................... 31

3.3.2Field FWD Deflection measurement ....................................................................................... 32

3.4Error Analysis .................................................................................................................................. 34

3.4.1Common sources of errors in FWD testing ............................................................................ 34

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3.4.2Common sources of errors in Roughness measurement........................................................ 34

3.4.3Common sources of errors in traffic counting ....................................................................... 35

CHAPTER FOUR ........................................................................................................................................... 37

4.0DATA PRESENTATION ............................................................................................................................. 37

4.1FWD’s Deflection Data .................................................................................................................... 37

4.2 Distress Survey Data ....................................................................................................................... 38

4.3Roughness Data ................................................................................................................................ 39

4.4Traffic Survey Data ......................................................................................................................... 41

4.5Pavement Thickness Data ............................................................................................................... 42

CHAPTER FIVE ............................................................................................................................................. 43

5.0 DATA ANALYSIS AND DISCUSSION ........................................................................................................ 43

5.1Roughness Data Analysis ................................................................................................................ 43

5.2Traffic Data Analysis ....................................................................................................................... 44

5.3Deflection Data Analysis .................................................................................................................. 47

5.4Surface Defect Analysis ................................................................................................................... 48

5.5Discussion.......................................................................................................................................... 48

5.5.1Pavement Roughness ................................................................................................................ 48

5.5.2Pavement Structural Adequacy ............................................................................................... 49

5.5.3Pavement Surface Defects ........................................................................................................ 49

5.5.4Traffic Loading ......................................................................................................................... 51

CHAPTER SIX ................................................................................................................................................ 52

6.0CONCLUSION AND RECOMMENDATIONS.............................................................................................. 52

6.1 Pavement Roughness ...................................................................................................................... 52

6.2Pavement structural adequacy ....................................................................................................... 52

6.3Pavement surface distress ............................................................................................................... 52

6.4Traffic Loading ................................................................................................................................ 52

6.5Recommendation .............................................................................................................................. 52

REFERENCES ................................................................................................................................................ 54

APPENDICES ................................................................................................................................................ 55

APPENDIX A ................................................................................................................................................. 55

A.SURFACE DISTRESS DEFECTS ..................................................................................................... 55

B.FWD DEFLECTION DATA .............................................................................................................. 64

C.PAVEMENT ROUGHNESS DATA .................................................................................................. 75

D.PAVEMENT THICKNESS ................................................................................................................ 81

E.ANALYSED ROUGHNESS DATA .................................................................................................. 83

F.TRAFFIC VOLUME COUNTS .......................................................................................................... 87

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List of Acronyms

AASHTO : American Association of State and Highway Transportation Officials

IRI : International Roughness Index

PI : Pavement Index

RN : Roughness Number

NAASRA : National Authority of Australian State Road Authority

PV : Profile Variance

PCI : Pavement Condition Index

RMSE : Root Mean Square Error

ANN : Artificial Neutral Network

GP : Generic Programming

MAE : Mean Absolute Error

RTRRMS : Response Type Road Roughness Measuring Systems

UK : United Kingdom

NZTA : New Zealand Transport Authority

DM I : Distress Manifestation Index

RCR : Ride Comfort Rating

MTO : Ministry of Transportation of Ontario

SDI : Surface Distress Index

PCR : Pavement condition Rating

DCP : Dynamic Cone Penetration

CBR : California Bearing Ratio

PR : Penetration Rate

ARRB : Australian Road Research Board

NCDOT : North Carolina Department of Transport

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List of tables TABLE 1.PAVEMENT QUALITY RATING .............................................................................................................. 6

TABLE 2.PAVEMENT SERVICEABILITY INDEX .................................................................................................. 7

TABLE 3.SURFACE DISTRESS DENSITY CONVERSION INTO PERCENTAGES. .......................................... 10

TABLE 4.SURFACE DISTRESS TYPE .................................................................................................................... 12

TABLE 5.SHOWING COUNTING ERROR ESTIMATES FOR DIFFERENT TRAFFIC TYPES. ........................ 35

TABLE 6.TRAFFIC VOLUME (ADT)-MERILE BARRIER .................................................................................... 44

TABLE 7.TRAFFIC VOLUME (ADT)-ISIOLO BARRIER ...................................................................................... 44

TABLE 8.BASELINE ADT ISIOLO MERILE .......................................................................................................... 45

TABLE 9.FWD BACK-ANALYSIS RESULTS OF KEY PARAMETERS. ............................................................. 47

TABLE 10.SEVERITY AND DENSITY ESTIMATES OF SURFACE DISTRESS TYPES ON A SECTION OF

ISIOLO MERILE ROAD. .................................................................................................................................. 48

TABLE 11.RECOMMENDED INTERVENTION. .................................................................................................... 53

TABLE 12.TYPES OF OBSERVED DEFECTS, SEVERITY AND THEIR LOCATION. ...................................... 55

TABLE 13.MEASURED ROUGHNESS. ................................................................................................................... 76

TABLE 14.SHOWING CALCULATED PSI AND IRI ............................................................................................. 84

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List of figures

FIGURE 1.MAP SHOWING ISIOLO MERILLE ROAD ............................................................................................ 2

FIGURE 2.RTRRMS FITTED VEHICLE. ................................................................................................................. 31

FIGURE 3.FLOW CHART OF RESEARCH ............................................................................................................. 33

FIGURE 4.ERRORS IN ADT ESTIMATES FROM RANDOM COUNTS OF VARYING DURATION. .............. 36

FIGURE 5.SHOWING DEFLECTION ON A SECTION OF ISIOLO MERILE ROAD. ......................................... 37

FIGURE 6.SHOWING CORRELATION BETWEEN NAASRA AND SPEED. ...................................................... 39

FIGURE 7.SHOWING CORRELATION BETWEEN IRI AND SPEED .................................................................. 39

FIGURE 8.SHOWING TRAFFIC COUNT ON MERILE BARRIER ON DIFFERENT DAYS. ............................. 41

FIGURE 9.SHOWING TRAFFIC COUNT ON ISIOLO BARRIER ON DIFFERENT DAYS ................................ 41

FIGURE 10.SHOWING ERROR LIMITS ON TRAFFIC VOLUME ANALYSIS. .................................................. 47

FIGURE 11.SHOWING LONGITUDINAL WHEEL PATH CRACK. ..................................................................... 50

FIGURE 12.SHOWING PAVEMENT EDGE CRACK. ............................................................................................ 51

FIGURE 13.PAVEMENT THICKNESS AT DIFFERENT SECTIONS. ................................................................... 82

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CHAPTER ONE

1.0 Introduction

1.1General

In order for the road users and the transport agencies to understand whether the pavement are

becoming less sustainable, evaluation of pavement condition against related indicators are

necessary with the ultimate purpose being to improve transportation services for the public. The

purpose of pavement evaluation is primarily to determine the condition of the existing pavement. A

sound pavement evaluation will;

enable the designer to assess the existing pavement and determine its current condition;

identify the causes of any observed pavement distress,

ascertain whether the existing pavement must be rehabilitated to withstand the predicted

conditions for the required design period; and

Provide the foundation for identifying what treatments/interventions are required, if any.

It is conducted to determine functional as well as structural conditions of a highway section. Functional

condition is mainly concerned with the ride quality or surface friction of a highway section (e.g. how the

road satisfies the needs of the road users in terms of cost, comfort, convenience and safety). On the other

hand, structural condition is concerned with the structural capacity of the pavement as measured by

deflection, layer thickness, and material properties (e.g. how it responds to load[s]).

Pavement evaluation can be used to determine whether a section of Isiolo – Merille River Road is

meeting its anticipated goals and objectives. The structural components of Isiolo - Merille consists

of four layers namely; surfacing which is the topmost layer and its purpose is to provide a smooth,

abrasion resistant, dust proof and a strong layer. The second layer of the pavement which comes

immediately below is the base which is the medium through which stresses imposed are distributed

evenly. The third layer is sub base layer which help in additional distribution of loads. The last

layer is the sub grade which is the compacted natural earth.

1.2 Study Area

Isiolo-Merille River Road forms part of the road corridor from Mombasa through Nairobi to Addis

Ababa.It is 139km (as shown in figure 1) long and forms the first section of the 520km road from

Isiolo to Moyale which links Kenya to Ethiopia.

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Figure 1.Map showing Isiolo Merille road

1.3 Problem Statement

Few people will dispute the fact that premature signs of distress are evident on some roads in

Kenya. Transport agencies spend more funds than anticipated to mitigate this problem (. But what

happens when these signs deteriorate and nothing is being done to reduce them?

Some sections of Isiolo -Merille river road shows clear manifestation of distress which includes;

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Longitudinal Cracks. They are usually type of fatigue cracking which runs parallel to the

pavement's centerline. The cracks allow moisture infiltration, roughness and may indicate

possible onset of alligator cracks and structural failure.

Traverse Cracks. They are usually type of thermal cracking which are perpendicular to the

pavement's centerline. They allow moisture infiltration as well as roughness on the

pavement.

Patches. These are areas of pavement that has been replaced with new material to repair the

existing pavement. A patch is considered a defect no matter how well it performs. It leads

to roughness.

1.4 Objectives

The main objective of this project is to evaluate the condition of a section of Isiolo-Merile Road

within the study period 2014 up to date. The data inventory which was established was from visual

condition survey, traffic surveys and testing.

Sub-objectives which were therefore set to achieve the main objective were to:

Carry out traffic volume count to estimate the capacity of the road section.

Identify the causes of any observed pavement distress.

Ascertain whether the existing pavement must be rehabilitated to withstand traffic loading.

Analyze and interpret the data.

Make suitable recommendations and economically viable ways of mitigating the problem.

1.5 Scope of study

To achieve the above stated objectives the project undertook the following tasks:

a) Identification of a suitable station for carrying out traffic count .These data will be analyzed

to determine the traffic loading on the pavement.

b) Conducting a distress survey to determine its extent and severity e.g. Presence of rutting

which may indicate overloading on the pavement.

c) Carrying out analysis on pavement structure. This information will then be used to

determine whether the pavement is structurally adequate for current and projected traffic

loadings.

1.6 Limitations of the study.

Traffic survey method was limited to manual count .This was due to complexity of other

methods which requires enormous resources therefore less accurate as compared to other

methods such as automated method.

The traffic survey was limited to one week.

Insecurity in the study area which made it difficult to conduct the test on certain

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CHAPTER TWO

2.0Literature review

2.1 General Introduction

This chapter includes the review of literature and other guidelines that were used in the

development of the information described in this report .It gives different evaluation techniques as

well as equipment employed by different researchers and road agencies in different countries to

evaluate flexible pavement condition.

2.2Functional Evaluation.

2.2.1Roughness.

Road roughness can be defined as the distortion of the road surface which imparts undesirable vertical

accelerations in the vehicle that contribute to an undesirable or uncomfortable ride (ASTM, 1999)

2.2.1.1Equipment

A variety of equipment has evolved over the years to measure pavement roughness; this equipment varies

among the highway agencies and has a range of design characteristics which are dependent on intended use.

Perera and Kohn (2002) found that devices could be divided into the following five categories:

Response-type road roughness measuring systems

High-speed inertial profilers/profilometers

profilographs

Light-weight profilers

Manual devices.

Until the mid-1980s, most highway agencies used the response-type road roughness measuring system

(RTRRMS) to measure road roughness. These devices measure the response of the vehicle to the road

profile, using transducers to accumulate the vertical movement of the axle of the survey vehicle with respect

to the vehicle body. The measurement directly reflects the user‟s feeling of ride quality.

A variety of RTRRMSs have been developed over the years, but all are disadvantaged by the fact that the

results are influenced by the suspension characteristics of the vehicle and the measuring speed, and do not

provide pavement longitudinal profile for spectral analysis. With the advent of inertial profilers, the use of

the RTRRMS has diminished for roughness measurements and most types of pavements.

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Inertial road profiling is a technology that began in the 1960s at the General Motors Research Laboratory

(Spangler and Kelley 1964). The number of countries that have adopted high-speed inertial profilers to

collect roughness data on their highway networks has shown a dramatic increase in the last two decades.

High-speed profilers collect pavement condition data at highway speeds and record sufficient data to monitor

pavement profile. The principal components of a high-speed profiler are laser-based height sensors,

accelerometers and an accurate distance measuring system. The height sensors record the distance to the

pavement surface from the vehicle. The accelerometers, located on top of the height sensors, record the

vertical acceleration of the sensor. Double integration of the vertical acceleration gives the vertical

displacement of the vehicle. The longitudinal profile is then derived from these two height measurements.

The distance measuring system ties the measurements to a reference starting point. The non-contact height

sensors currently used in profilers are either laser or ultrasonic waves.

Unlike the high-speed laser profiler, a profilograph consists of a rigid beam or frame with a system of

support wheels at either end and a central wheel. This wheel is linked to a strip chart recorder or a computer

that records the movement of the wheel from the established datum of the support wheels. The major

difference between the high-speed profiler and the profilograph is that they use different reference planes

and different filtering to record the surface profile. The profiler is a network survey device while the

profilographs are widely used to evaluate the as-constructed smoothness of new pavements and overlays.

Light-weight profilers are increasingly used to evaluate new construction. The term lightweight profiler

refers to devices in which a profiling system has been installed on a light vehicle, such as a golf cart or an

all-terrain vehicle. The profiling system in the light-weight profilers is similar to ones used in high-speed

profilers. The profile data is commonly used to simulate a profilograph over the pavement section, generate a

profile index (PI) and identify bump locations.

2.2.1.2Roughness indices

Commonly used roughness indices include the IRI, PI, RN, RMSVA, National Association of Australian

State Road Authorities (NAASRA) count and profile variance (PV).

The IRI is a widely accepted measure of roughness developed by the World Bank in the 1980s and adopted

by the World Road Association (PIARC). The IRI is a numerical representation of a road profile, designed to

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replicate the traditional roughness measures obtained from response-type road roughness measuring systems.

The computation of the IRI is based on a mathematical model called the quarter-car model. This

mathematical model calculates the suspension deflection of a simulated mechanical system with a response

similar to a passenger car. The IRI has been found to be highly portable, that is, different roughness or

profile measuring devices are capable of producing outputs expressed in the IRI.

Table 1 provides the pavement condition criteria for all functional road classifications in the

national highway system. Several jurisdictions have explored PCI-IRI relationships for highways

with acceptable statistical validity

Table 1.Pavement Quality Rating

Park et al. established a power relationship between PCI and IRI using data from nine states and provinces in

Northern America. The IRI-PCI data set used in the study used were extracted from the DataPave program

for highways in the regions of Delaware, Maryland, New Jersey, New York, Vermont, Virginia, Ontario,

Quebec and Prince Edward Island and spanned the period from 1991 through 2000. The power model

proposed was led to the following equation:

(2.1)

The R2 value of the model was determined to be 59%. The plots of the residuals and normal scores were

used to confirm the normality and homoscedasticity of the model‟s distribution.

In 2012, Shahnazri et al. [6] estimated PCI values from other pavement indices (other than IRI) based on

different types of distresses and severity levels using two optimization techniques: artificial neural networks

(ANN) and genetic programming (GP). The models were developed based on PCI data gathered from more

than 1,250 km of highways in Iran. A feed forward ANN was used with the network being trained using the

back propagation method. In addition, the root-mean square error (RMSE) fitness function was used for the

GP approach. From the results, the ANN- and GP-based projected values were determined to be in good

agreement with the field-measured PCI values. The reported R2,

RSME and mean absolute error (MAE) for the ANN-based models were respectively 0.9986, 0.99, and 0.49,

whereas they were equal to 0.9898, 2.63, and 1.79 respectively for the GP-based model.

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Sayers, et al.(1986) proposed the formula to calculate the PSI value in function of IRI value as shown in

equation (2.2), considering the crack failure, patching and rutting that have been included in the IRI value.

PSI =5 × e(-0.18×IRI)

(2.2)

Where; PSI =Present serviceability index

IRI=International Roughness Index

Sayers,et al.(1986), proposed also the pavement condition based on the PSI value, as shown in table 2.2

Table 2.Pavement Serviceability Index

PSI Condition

4≤ PSI <5 Very Good

3≤ PSI <4 Good

2≤ PSI <3 Fair

1≤ PSI <2 Bad

0≤ PSI <1 Very Bad

Source: Sayers,et al.(1986)

Another model for IRI as a function of PCI was developed for the Bay Area cities and counties in California

with the intent of using the model in estimating user costs/benefits in their pavement management system.

The resulting model was:

(2.3)

Where IRI is in m/km.

The model's R2

value was 0.53 with a coefficient of variation of 28%. The actual and predicted

values of IRI were compared graphically to depict the dispersion of data and for model validation.

A 2002 study conducted using data from varied highway pavement sections from the North Atlantic

region in the United States and Canada resulted in the development of a relationship between the

PCI and IRI. The model confirms the acceptability of the IRI as a predictor variable of the PCI

based on the existence of the resulting strong correlation between the two variables (from the

ANOVA) and an R2 value of 0.66 for the model. In addition, the results showed acceptable

corresponding p-values from

the ANOVA and t-tests for this model which also suggest the acceptability of IRI as a predictor variable of

PCI at a 99% significance level.

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The RN is an index intended to indicate ride quality on a scale similar to the PI. The RN uses a scale from 0

to 5. This scale was selected, as it is familiar to the highway community. The RN is a nonlinear transform of

the PI that is computed from profile data. The PI ranges from 0 (a perfectly smooth profile) to a positive

value proportional to roughness. The PI is transformed to a scale that goes from 5 (perfectly smooth) to 0

(the maximum possible roughness). RMSVA is a statistic that measures the root-mean-square of the rate of

change of the grade of a pavement longitudinal profile. The method was named RMSVA for two reasons.

First, the computation is equivalent to the second derivative of the height with respect to the time of the

object in contact with the profile moving at a constant horizontal speed. Such computation yields a vertical

acceleration of the object. Second, a series of acceleration values result from the discrete elevation points;

therefore, a root mean square of these values is computed to arrive at a single value (Hudson et al 1983). The

RMSVA can be computed for any base length. The capacity provides the technique with a strong ability to

distinguish between the various components of the roughness that exists in a pavement longitudinal profile.

Since the early 1970s, road pavement roughness has been measured in Australia and New Zealand using the

NAASRA roughness meter. This is a standard mechanical device for measuring road roughness by recording

the upward vertical movement of the rear axle of a standard station sedan relative to the vehicle‟s body as the

vehicle travel at a standard speed along the road being tested. The NAASRA meter is classified as a

response-type road roughness measuring system (RTRRMS). NAASRA roughness counts per kilometer is

the cumulative total relative upward displacement between axle and body of a standard vehicle, registered in

units of counts per kilometer of distance travelled at either of two principal standard speeds, 80km/h or

50km/h. One NAASRA roughness count corresponds to a measured axle-to-body separation of 15.2mm.

Although NAASRA roughness meters have been successfully used for many years, there are particular

concerns about maintaining their calibration, and about repeatability and reproducibility of the results.

Outputs are very dependent on vehicle suspension characteristics (eg, shock absorbers, springs, tyres) and

the speed of travel (Austroads 2000).

In the United Kingdom, ride quality is assessed by profile variance (UK Roads Board 2003), obtained by

calculating the differences between the profile and its moving average over selected moving average lengths.

Three moving average base lengths (3m, 10m and 30m) are commonly used and accordingly, the road profile

data is processed to compare the actual profile and the moving average of the profile

over these three lengths. The results are presented in terms of the square of the difference between the

moving average of the profile

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and the measured profile. Profile variance is also used by some Commonwealth countries, for instance

Singapore and New Zealand. In a research report recently published by the NZTA, Jamieson (2008)

developed a methodology based on road profile variance to identify and prioritize treatment of road sections

that promote poor ride quality for heavy commercial vehicles. In the study, he found that high values of

profile variance, particularly in the 10m and 30m wavelength data, generally corresponded to locations

exhibiting poor truck ride quality in the measured on-road data. However, there were many sections with

high-profile variance that did not show poor truck ride. If profile variance is to be used successfully to select

and prioritize road section for remedial work the profile variance must first be modified or filtered

according to geometry factors and/or vehicle speed.

In New Zealand, Agrawal and Henning (2005) carried out research for RIMS Group and some

participating councils to analyze the roughness data measured by an inertial profilometer on urban

networks and to provide guidelines to improve the quality of roughness data. The key findings of

this study were as follows:

Steep gradient and tight curves had an impact on roughness readings. High

roughness was observed on sections with a gradient greater than 10% and curves

with a radius of less than 100m.

Some sections had high roughness, particularly the start and end 40m, compared

with the remaining length.

The roughness at roundabouts was at unacceptable levels. The readings before and

after the roundabouts also showed elevated roughness.

High roughness was noticed for the data collected at low speed. The average

roughness was up to 9 on the IRI at speeds less than 30km/h.

Event codes were extremely under-utilized during data collection. A variation in

roughness of up to 36% was observed between successive surveys on a sample

network.

2.2.2Distress Evaluation

Distress evaluation is one of the important steps in pavement evaluation, which in turn, is

the most critical component of any pavement management system. An indication of the

importance of distress data is the fact that distress indexes are used as the common measure

of pavement quality in many pavement management systems. Pavement distress types are

10

usually grouped in different classes depending on the viewpoint of the evaluator and the

purpose of the survey. These groups might be (Rezqallah 1997):

Type-Wise grouping: cracking, surface deformation, surface defect, and others,

Pavement –type grouping: flexible or rigid pavement distresses,

Failure type – wise grouping: structural or functional failure distresses,

Cause-wise grouping: load associated, environmental, builtin cause, and construction

practice associated distresses

location-wise grouping : localized or wide-spread distresses, and

Performance-wise grouping: riding quality, skid resistance, or structural related

distresses.

In order to obtain an overall assessment of pavement conditions for a road network, it is

often necessary to combine individual distress data to form one composite index which

summarizes the condition of each pavement section or segment or project (Haas et al.1994).

The composite index will help in deciding whether to repair a section with alligator cracking

or rutting. Also density and severity of different distresses will indicate that one pavement

section is in a worse state than another pavement with a different set of distresses (Haas et

al. 1994). The composite distress index summarizes the pavement condition in terms of

individual distress, so that pavement condition may be evaluated, predicted, and improved

using effective treatments. Distress evaluation, or condition survey, includes detailed

identification of pavement distress type, severity, extent, and location. To combine these

details, an index is assigned to each pavement which is transferred to a general rating.

In almost all distress evaluation methodologies, each distress is specified by severity level

(low, medium, or high) and an extent level described in measurable units linear or area) or

descriptive measure ( few, intermittent, frequent, or extensive). Each distress type, severity

level, and extent level combination is assigned a deduct value which is an indication of how

this combination, when available, affects the perfect pavement (Haas et al.1994)i.e

Table 3.Surface Distress Density Conversion into Percentages.

Distress Type Density Basis for Calculation and Acceptable

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Measure Density Value

Longitudinal wheel path

cracking

Linear Total combined length of cracking

measured in each wheel path divided by

the segment length 2(i.e100m)

Longitudinal joint cracking Total length of crack measured divided by

the segment length.

Pavement edge cracking Total length of crack measured divided

by the segment length

Meandering longitudinal

cracking

Total length of crack measured divided

by the segment length.

Bleeding Total length of bleeding measured in

each wheel path over combined 100m

wheel path length.

Traverse cracking Number 0%-no traverse cracking is present

5%-few(1-2cracks)

35%-frequent(3-10cracks)

90%-throughout(>10 cracks)

Potholes 0%-none

5%-few(1-2potholes)

35%-frequent(3-9potholes)

90%-throughout(>10potholes)

Alligator cracking Area 0%-none

5%-few

15%-intermittent

35%-frequent

65%-extensive

90%-throughout

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Rutting Segment 0%-neither wheel path rut depths

are3mm

35%-only one wheel path rut depths

is3mm

90%-both wheel path rut depths

are3mm

Table 4.Surface Distress Type

Distress Type Severity

Low Moderate High

Longitudinal Wheel Path

cracking

Single cracks with no

spalling;mean unsealed

crack width<5mm

Single or multiple

cracks; moderate

spalling; mean

unsealed crack width

5-20mm

Single or multiple

cracks; severe

spalling; mean

unsealed crack

width>20mm;alligator

Longitudinal Joint Cracking Single crack with no

spalling ;mean unsealed

crack width<5mm

Single or multiple

cracks; moderate

spalling; mean

unsealed crack width

5-20mm

Single or multiple

cracks; severe

spalling; mean

unsealed crack

width>20mm;alligator

Pavement Edge cracking Single crack with no

spalling ;mean unsealed

crack width<5mm

Single or multiple

cracks; moderate

spalling; mean

unsealed crack width

5-20mm

Single or multiple

cracks; severe

spalling; mean

unsealed crack

width>20mm;alligator

Traverse cracking Single crack with no

spalling ;mean unsealed

crack width<5mm

Single or multiple

cracks; moderate

spalling; mean

Single or multiple

cracks; severe

spalling; mean

13

unsealed crack width

5-20mm

unsealed crack

width>20mm;alligator

Meandering Longitudinal

cracking

Single crack with no

spalling ;mean unsealed

crack width<5mm

Single or multiple

cracks; moderate

spalling; mean

unsealed crack width

5-20mm

Single or multiple

cracks; severe

spalling; mean

unsealed crack

width>20mm;alligator

Alligator/crocodile

cracking

Not rated Interconnected cracks

forming a complete

block

pattern;slightspalling

and no pumping

Interconnected cracks

forming a complete

block pattern

,moderate to severe

spalling ,pieces may

move and pumping

may exist

Rutting Less than 10mm 10 to 20mm Greater than 20mm

Shoving Barely noticeable to

noticeable

Rough ride Very rough ride

Distortion Not rated Noticeable swaying

motion;good car

control

Fair to poor car

control

Bleeding Not rated Distinctive

appearance with free

excess asphalt

Free asphalt gives

pavement surface a

wet look ;tire marks

are evident

Potholes Less than 25mm deep

and greater than 175cm2

in area

25 to 50mm deep and

greater than 175cm2

in area

Greater than 50mm

deep and greater than

175cm2 in area

Ravelling Not rated Aggregate and /or

binder worn away;

Aggregate and /or

binder worn away

14

surface texture rough

and pitted loose

particles exist

;surface texture is

very rough and pitted

In 1950, a regression equation (Roberts et al. 1991) known as Present Serviceability Index was developed to

evaluate the pavement serviceability based on measurable pavement distresses and a quantifiable measure of

the pavement evaluation.

The PSI is determined as follows:

PSI = 5 – 1.91log (1+SV) – 1.38 (RD) 2 – 0.01 (C+P)

0.5 (2.4 )

Where SV = slope variance

RD = average rut depth

C = pavement cracking in feet/1000 square feet of pavement surface and

P = patching in square feet /1000 square feet of pavement surface

In 1962, AASHTO (Roberts et al. 1991) studied a quantifiable measurement of pavement distress types. The

Present Serviceability Index was established by AASHTO during the study. This index is a number which is

indicative of the pavement ability to serve traffic and it's based on combination of profile meter readings

(roughness) and visual inspection (surface distress types). In this method, each distress included is

considered as an independent variable, and all the independent variables combined linearly or nonlinearly to

reproduce the user ratings based on pure data fitting. The developed index ranges from 0 to 5 as follows:

4 – 5 very good

3 – 4 good

2 – 3 fair

1 – 2 poor

0 – 1 very poor

Pavement condition was investigated in 1981 by US Army Corps of Engineers (Shahin 2002). The study was

resulted in development a single rating number called Pavement Condition Index (PCI) using the PAVER

method to represent pavement condition. PAVER is one the most detailed distress evaluation method

implemented to data. This method depends on detailed visual inspection of up to 19 different pavements

distresses for flexible pavement. The PCI is a numerical index, ranging from 0 for a failed pavement to 100

for a pavement in perfect condition. It measures pavement structural integrity and surface operational

condition. The essential concept behinds PCI is to consider each given distress severity and amount as a

15

negative deduct on pavement condition. The PCI index uses only one pavement condition parameter which is

distress types in determining the pavement condition index.

The PCI is determined as follows:

PCI = C-∑ ∑ a (Ti, Sj, Dij) ×, Dij) x F (2.5)

Where, T i = distress type

S j = severity level.

D i j = density of distress.

C = constant (usually 100).

a = weighing factor.

F = adjustment factor for multiple distress.

Baladi (Wang 2000) proposed a procedure for formulating pavement condition index for individual distress.

There are several steps in this process, which starts with the identification and determination of types of

distress, severity levels for each type of distress, and the determination of a rating scale, such as 0 to 100.

Based on these definitions and the rating scale, a panel of engineers is asked to determine the maximum

tolerable density for each type-severity distress before any treatment will be scheduled. This density level is

hence designated as the threshold deduct-value, or the so-called engineering criterion for that particular type-

severity distress. Finally, deduct-values for other density levels for the same type-severity distress are

obtained by linearly scaling up and down according to the designated engineering criterion. This process has

been adopted by North Carolina and South Dakota.

The Ministry of Transportation of Ontario (MTO) (MTC 1980) uses two parameters to evaluate the

pavement condition. The two parameters are: Distress Manifestation Index (DMI) and the Ride Comfort

Rating (RCR). The DMI is a composite subjective measure (or a multi – attribute) of extent and severity of

pavement distress manifestations. 15 distress types that are evaluated for asphalt concrete pavements

grouped into three categories: surface defects, surface deformation and cracking. The severity of distress is

rated in five categories ranging from very slight to very severe. Extent (or density) is also classified in five

categories ranging from few (less than 10 %) to throughout (more than 80 %). The severity and density

weighting factors to calculate each distress index which equates to severity on a scale 0.5 to 4 and density on

a scale 0.5 to 4.0. The developed formula to calculate the DMI is;

DMI = ∑ wi (s i + d i) (2.6)

16

Where wi = weighting value representing the relative weight of a distress manifestation

In China (Wang 2000) Sun and Yao adopted the deduct-value concept in formulating the distress indexes for

asphalt pavements. The proposed a different procedure for Pavement Distress Index (PDI) based on a

different set of distress definition and measuring method. Three major's steps in this method, namely

standardization of distress classification and measurement, formulation of PDI, Finally determination of the

weight function.

One of five indices developed for Pennsylvania models (Chen et al. 1995) was Surface Distress Index (SDI)

which relates seven distresses together. These distresses are; Excess Asphalt, Raveling and Weathering,

Block Cracking, Transverse and Longitudinal Cracking, Edge Deterioration, Widening Drop-off, and

Rutting.

The Surface Distress Index is equal to

(SDI) = 0.1(Excess Asphalt) + 0.13 (Raveling and Weathering) +

0.20 (Block Cracking) + 0.25 (Transverse and Longitudinal Cracking) + 0.05 (Edge Deterioration) +

0.12 (Widening Drop-off) + 0.15 (Rutting). (2.7)

The North Dakota study (Johnson and Cation 1992) developed overall distress, structural and roughness,

performance curves for 42 different performance class pavements. The original pavement data was

categorized into groups based on similar characteristics such as surface type, traffic and structure. These

groups (or families) were then analyzed to develop performance curves. This approach assumes that

pavements with the same grouping will perform similarly throughout their lives. This method is easy to

understand and modify in the future. The research investigated the use of linear regression analysis, the

AASHTO power function, and non-linear analysis. It was found that non-linear analysis in the form of a

fourth degree polynomial, gave the best results for distress and structural indices. For example, the average

distress index R2 for 42 classes of pavements was 0.77.

17

An extensive research was done by Phang and Stott (1981) on Brampton road test in Canada to study the

progress of distresses prior to maintenance work over the passage of time and traffic. The distress

Manifestation, (DM), assigned to a pavement at any time is the summation of the weighted values for

condition (severity and extent) of each type and class of pavement distress present. If the component

weighted values for each type of distress is examined over a period of time, one can trace the progression of

that specific distress and perhaps determine whether certain types of distress lead to rapid failure, and as

well, perhaps note those distresses which are not critical. The weighting for each distress type and class

derived through iterative correlation with the performance of many thousands of kilometers of highway, do

in fact, indicate a relative deterioration gradient applicable to the specific distress.

United States of America (USA)

Case Study 1: Louisiana – Combination of pavement distress and ride quality

The Louisiana Department of Transportation uses a Pavement Condition Rating (PCR) system obtained by

combining ride quality and pavement distress data. Ride quality is collected using a Mays Ride Meter

profilometer. The data collected are used to determine the vertical motion of a vehicle caused by

irregularities in the pavement surface. The data are reported in inches per mile.

Pavement distress data is based on visual evaluations of standard pavement distress patterns: cracking,

raveling, and patching. A subjective estimation of the severity and extent of those distress patterns is

assigned by the survey team. Pavement distress rating values in Louisiana are road type dependent. Rural

roads showing no distress receive a rating of twenty-five while urban roads with the same condition only

receive a rating of twenty. Roads with total distress receive a rating of zero. (Shah, 1987)

Case Study 2:Washington State – Combination of structural condition, Pavement condition rating

,pavement rutting and surface roughness.

To monitor their highway system conditions, Washington State looks at pavement structural condition

(PSC), pavement rutting condition (PRC), and surface roughness.

Structural condition is based on a visual evaluation of typical pavement distress patterns; cracking, raveling,

and patching. A subjective estimation of the severity and extent of distress is used to assign the pavement

distress rating and assess structural condition.

18

Washington State weighs the effect of pavement distress differently for flexible versus rigid pavements in

the calculation of an overall PSC value.

For flexible pavements, the pavement condition survey is used to evaluate alligator cracking, longitudinal

cracking, transverse cracking and patching. The developed Pavement Condition Rating (PCR) is a measure

of the observed pavement surface distress and ranges from 100 (no distress) to 0 or below (extensive surface

distress). PCR is primarily determined by measures of the extent and severity of pavement surface cracking.

The final pavement condition rating (PCR) is a combination of the visual rating and ride rating:

PCR = [100 - ∑ D] [1.0 – 0.3 {CPM/5000} 2] (2.8)

Where ∑ D is the sum of the detect values, and CPM is the counts per mile

The second component in Washington State‟s pavement evaluation plan is to monitor pavement rutting

conditions. As do most other states, a profilometer is used to determine the extent of rutting. Because there

are numerous methods available for measuring ride quality, Washington State has adopted the International

Roughness Index (IRI) to standardize roughness measurements across the state. The IRI is a mathematically-

defined statistic of the profile in the wheel path of a road surface and is representative of the vertical motion

a vehicle experiences in response to the pavement surface (WSDOT, 1994).

Case Study 3: Oregon – Qualitative Good-Fair-Poor visual ratings

Oregon uses two different pavement condition evaluation systems, one for national highways and one for

non-national highways. For interstates and national highways, pavement distress surveys similar to the

methods used by Washington State are used to evaluate pavement condition. The surveys are conducted by

engineering student interns following an extensive week-long workshop for training. Non-national highways

are evaluated using a more subjective “windshield survey” of overall pavement conditions at highway speeds

by full-time ODOT employees. The overall pavement condition is then given a Good-Fair-Poor (GFP)

rating. No specific pavement distress information is collected (Oregon DOT, 2004).

Case Study 4: Maine – Quantitative digital video-based evaluation system

19

Unlike either Louisiana or Washington State, the state of Maine bases pavement condition ratings entirely

on quantitative analysis of pavement surface conditions. An ARAN (Automated Road Analyzer, Section 2.2)

is used to collect continuous digital video data of the road surface and GPS data at highway speeds. The

ARAN collects information on:

Shim qualities

Gradient and slope of the surface

Rut depth

Radius of curvature

Road smoothness

Right-of way data

Unlike other states, Maine‟s DOT is able to quantitatively evaluate the severity and extent of pavement

distress by analyzing the digital video images with WiseCrax, a pattern recognition software package. Maine

estimates that prior to implementation of ARAN with WiseCrax, only 4% of the highway network was being

evaluated and that pavement condition rating was being applied to the entire network. With automated data

collection and processing, the state of Maine can now sample 100% of the road surveyed. Pavement

management engineers attribute more efficient use of highway funds with such automated PCR capabilities

(Watson, 2003).

2.3Structural Capacity Evaluation. Structural evaluation of pavements commonly involves applying a standard load to the pavement and

measuring its response. The response measured can be stress, strain or deflection. The most commonly

measured response is deflection. Benkelman has been among the earliest equipment used for structural

evaluation of pavements. Since its development in 1953, the Benkelman Beam has become a standard tool

used by several agencies for nondestructive testing of pavements. Significant developments have taken place

since then in the equipment used and the analytical tools adopted for the evaluation of pavements.

Depending on the duration of the load applied, this equipment are broadly classified under two categories-

static

dynamic

2.3.1 Static / Creep Loading Equipment

In this category, either a static or a slow-moving load is applied to the pavement surface and the resulting

deflections are measured at one or more locations. Plate load testing, deflection measurement using

equipment such as Benkelman beam, Double Benkelman beam, Multiple Benkelman beam, Modified

Benkelman beam, Lacroixdeflectograph, Traveling deflectometer, etc., can be considered under this

20

category. Benkelman Beam [Zube and Forsyth, 1966] is a 3.66 m long, portable instrument used to measure

surface deflection of the pavement loaded by the rear axle of a standard truck. The main disadvantages with

this equipment is that the support legs of the beam often lie within the deflection basin, which affects the

measured deflections, measurement is slow and the radius of curvature is not measured. Also, a single

deflection does not give adequate information about the condition of various layers of the pavement. Double,

multiple and modified Benkelman beams have been used to measure deflections at different radial distances

under static loading condition. The LacroixDeflectograph [Nondestructive Testing- LacroixDeflectograph,

2003] is essentially a truck-mounted Benkelman Beam, which moves forward with the vehicle. Testing with

this equipment is faster compared to Benkelman beam. The Traveling Deflectometer [Zube and Forsyth,

1966] developed by the California division of highways has dual probes to simultaneously measure the

deflections between each set of dual wheels. CEBTP Curviameter [Paquet, 1978] is another device that

operates on the principle of Benkelman beam and measures not only the pavement surface deflections, but

also the radius of curvature of the pavement deflection bowl, which is more useful for evaluating the

pavement strength. Though deflection measurement under static load is simple, it does not simulate the

loading conditions produced by a moving vehicle in pavements. The evaluation of pavements by such

methods is, in general, slow.

2.3.2Dynamic Loading Equipment

Two types of devices are, in general, considered in this category. While vibratory loading is produced in one

category of equipment, the other category consists of impulse loading equipment. Dynaflect, Heavy Vibrator

and Road Rater are some of the vibratory equipment used for pavement evaluation. Falling Weight

Deflectometer (FWD), Loadman Portable FWD and Rolling Weight Deflectometer (RWD) fall into the

category of impulse equipment. Dynaflect pavement testing device [Scrivner et al, 1966] produces sinusoidal

vibration at a frequency of 8 Hz. It is fitted with five velocity transducers (geophones), each spaced 305 mm

apart. The output from the transducers is integrated to measure pavement deflection. The use of the Shell

heavy vibrator for pavement evaluation was reported by Heukelom and Foster [1960], Heukelom and Klomp

(1962), Nijboer and Metcalf [1962], and Jones et al [1967]. In this method, the modulus of elasticity of each

layer can be computed from the wave velocity and wavelength for a spectrum of frequencies of oscillation.

In Road Rater [Hoffman and Thompson, 1982], a dynamic force is applied by a steel mass accelerated by a

servo-controlled hydraulic actuator. Deflections are measured using four or more transducers. Load

magnitudes vary for different models.

Road Rater is available as trailer mounted and in-vehicle models. Though the vibratory equipment is useful

for structural evaluation of pavements, they are not very popular because of certain limitations. In the case of

Dynaflect, the maximum peak-to-peak force that can be applied is 1000lb. Magnitude and frequency of load

21

cannot be varied. The main drawback of Heavy vibrators is that they can operate only at slow frequency

rates. Heavy static (or seating) loads are required. The technical limitations of Road Rater device are: -

limited load level for some models and

high static pre-load for heavier models which changes the stiffness of the material and produces

deflections that are not representative of a moving wheel load.

The development of an impulse loading equipment, which closely simulates the timing and amplitude of a

rolling wheel load, began in the sixties. Isada [1966] reported the use of a falling mass device to study the

seasonal changes in the strength of flexible pavements. Bonitzer and Leger [1967] and Bohn et al [1972]

discussed about the evaluation of pavements using Falling Weight Deflectometer (FWD). This equipment

has undergone several improvements over the last three decades. Some of the current FWDs have

sophisticated features such as electronic distance measurement, and Global Positioning System (GPS)

hardware to make the equipment more versatile. Major applications of the FWD are in the following areas.

Evaluation of structural capacity of in-service flexible, semi-rigid and rigid pavements.

Quality control of sub grade and granular layers of pavements during the construction stage.

Assessment of the need for and design of thickness of overlays.

Determination of the rate of deterioration of pavement structures.

Evaluation of the degree of bonding between pavement layers

Assessment of equivalent moduli of concrete blocks in block pavements.

Evaluation of the load transfer capacity in the joints of concrete pavements.

Detection of voids under rigid pavements. The operating principle of FWD and the salient

features of a few commercially available models of FWD are discussed in the following

paragraphs.

2.3.2.1Some commercially available FWD models .

Some of the commercially available FWD models are:

Dynatest (with manufacturing facilities in Denmark and the United States)

KUAB (Sweden)

JILS, Foundation Mechanics, Inc. (United States) and

Carl Bro (Denmark)

22

In addition to the above-mentioned models, Komatsu company of Japan also manufactures FWDs [Irwin,

2002].

There are a few other models of FWD that were developed in small numbers by individual entrepreneurs and

academic institutions. The two models developed at IIT Kharagpur in India [Kumar et al, 2001; Reddy et al,

2002] can be listed in this category.

2.3.2.2Variations of FWD

There are some variations on the equipments as well. LOADMAN [Livneh et al, 1995] is a portable FWD,

available in two models (light and heavy weight) and is currently used by many organizations. The heavier

version of this model is mounted inside a vehicle [Loadman, 2003]. It is used for compaction control of

bound and unbound layers and for measuring the bearing capacity of the pavement. Rolling Wheel

Deflectometer (RWD) is the most recent and advanced NDT equipment for evaluating pavements. RWD

device measures pavement deflections under an 80kN rolling wheel load using a laser sensor. Designed to

operate at 56KPH, the RWD can travel at highway speeds and cover greater distances than a standard FWD.

It gathers real-time deflection data as it travels [Bay and Stokoe II, 1998; Rolling Wheel Deflectometer,

2003]. There is no risk to workers and no decrease in the traffic-carrying capacity of the highway while

deflection measurements are taken.

2.3.2.3Dynamic cone penetrometer

Pavement dynamic cone penetrometer is used for rapid in-situ strength evaluation of sub grade and other

unbound pavement layers. It is a simple, economical method, requires minimum maintenance and provides

continuous measurements of the in-situ strength of pavement section and the underlying subgrade layers

without the need for digging the existing pavement as in the California Bearing Ratio (CBR) test. The

dynamic cone penetrometer consist of an upper fixed 575 mm travel rod with 8 kg falling

weight, a lower rod containing an anvil, and a replaceable cone with apex angle of 60° and having a diameter

of 20 mm. The test is conducted by dropping the weight from 575 mm height and recording the number of

blows for any specified penetration. Then the penetration rate, PR (sometimes referred as DCP ratio, or

penetration index PI) is calculated. The DCP has the ability to verify both the level and uniformity of

compaction, which makes it an excellent tool for quality control during pavement construction. It has been

demonstrated that the results from penetration tests correlate well with the in-situ CBR values. There is a

strong correlation between CBR and DCP penetration ratio in log-to-log form and CBR-DCP relationship is

not significantly affected by changes in moisture content for granular layers. During the past decade, the

23

DCP test has been correlated to many engineering properties such as the CBR, shear strength of granular

materials, and most recently, Sub grade Resilient Modulus (MR), Elastic Modulus (E) and the soil

classification.

The Transvaal Roads Department of South Africa started using the DCP in 1973 to evaluate the pavement

structure of existing roads, as reported by Kleyn (Kleyn 1975). Based on lab testing results, Kleynfound that

when a DCP reading is plotted against a CBR on a log-log chart, the relationship is linear.Kleyndevoted

much effort to finding a way to use the DCP curve as an indicator of pavement condition, but he found no

pattern that would provide such an indicator. Yet when comparing sound pavement sections with failed

pavement sections, he noticed there appeared to be a minimum strength or suitability for the base course.

From this study, he concluded that DCP testing is highly repeatable and sensitive enough for use in practice.

He further suggested that DCP testing can be used to assess earthwork construction quality, evaluation of

pavements, and design of pavements.

The Australian Road Research Board (ARRB) (Smith and Pratt, 1983) developed an empirical correlation

between PR and CBR, which is:

Log (CBR) = 2.56 - 1.15 Log (PR) (2.9)

The North Carolina Department of Transportation (NCDOT) (Wu, 1987) developed the following DCP and

CBR relationship, based on the field CBR and the average of three DCP readings taken within an area with a

radius of less than 1 ft (0.3 m) around the CBR test location:

Log (CBR) = 2.64 – 1.08 Log (PR) (2.10)

DCP tests are designed to estimate the structural capacity of pavement layers and embankments. Livneh et al.

(1989) demonstrated that the results from penetration tests correlate well with the in-situ CBR values.

LivnehandIshai (1987) conducted a correlative study between the DCP values and the in-situ CBR values.

During this study, both CBR and DCP tests were done on a wide range of undisturbed and compacted fine-

grained soil samples, with and without saturation in the laboratory. Field tests were performed on natural and

compacted layers representing a wide range of potential pavement and sub grade materials. The research

resulted in the quantitative relationship between the CBR of the material and its DCP-PR value and is shown

in Eqn 2.12

Log CBR = 2.2 – 0.71 (log PR) (2.11)

Chen et al. (2001) indicated that the DCP can be useful when the Falling Weight Deflectometer (FWD)

back-calculated resilient moduli is not accurate, such as when the asphalt concrete layer thickness is less than

24

75 mm or when bedrock is shallow . The sub grade resilient modulus, which is used in design methods based

on structural analysis, can be determined either indirectly from relation between sub grade modulus (Es) and

CBR or can be predicted directly from the DCP results. The 1993 AASHTO Guide for Design of Pavement

Structures has adopted the Eqn. 2.13 for calculating sub grade resilient modulus (MR), which was proposed

by Huekelom and Klomp(1962).

MR (MPa) = 10.34 CBR (2.12)

The resilient modulus from which this correlation was developed is limited to fine-grained soils with a

soaked CBR of 10 or less. Powell et al. (1984) suggested relationship between sub grade resilient modulus

and CBR as shown in Eqn. 2.14. Other Equations relate the DCP Penetration Ratio (PR) with the sub grade

modulus directly. Pen (1990) suggested the two relationships between the sub grade elastic modulus (Es) in

(MPa) and PR in (mm/blow) as defined in Equations 2.15 and 2.16

MR (MPa) = 17.58 × CBR 0.64

(2.13)

Log (Es) = 3.25- 0.89 log (PR) (2.14)

Log (Es) = 3.652-1.17 log (PR) (2.15)

2.3.3Backcalculation of pavement layer moduli

The response measured with the FWD is the surface deflection of the pavement at different distances from

the centre of the load. The measured deflections along with other relevant information are used as inputs

either to back calculate the effective pavement layer moduli for use in analytical evaluation methods or to

estimate the overlay requirement from empirical relationships. Salient features of some existing back

calculation procedures are presented in the following sections. Determination of Young‟s

modulus of elasticity for pavement materials using measured surface deflections by working “backwards” is

generally called “Back calculation”. More specifically, it is the process of selection of layer moduli using a

suitable technique (iteration, database searching, closed-form solution, and optimization) so that the

deflections computed using the layer moduli are close to the measured deflections.

Scrivner, et al. [1973] developed the first closed-form solution for two-layer pavement system based on

Burmister’s [1945] layer theory. The first closed-form solution for back calculating layer moduli for multi-

layer pavements was developed by YihHo[1977] using least squares method. The first graphical method for

determining the moduli of two layer pavements was developed by Swift [1973]. Odemark’s [1949]

equivalent layer concept was used in some back calculation models to simplify the pavement systems and

25

thereby facilitate the use of Boussinesq's theory for the analysis of pavements. The back calculation method

developed by Ullidtz [1987] is based on this concept and reportedly gives reasonable layer modulus values

for pavements in which the layer stiffness decreases with depth. Lytton and Michalak [1979] used a more

general form of Odemark’s assumptions to convert a multi-layered pavement into a single layer placed above

a rigid base. With advances in the computational facility, a number of computer based backcalculation

programs are available now.

Efforts were also made in the past to estimate sub grade modulus from the surface deflections measured

during NDT evaluation. AASHTO [1993] recommends backcalculation of the sub grade resilient modulus

from a single deflection measurement, using the following equation.

MR=0.24P/dr × r (2.16)

Where MR = backcalculatedsub grade resilient modulus (psi);

P = applied load (pounds);

dr = deflection at a distance „r‟ from the center of the load (inches);

r = distance from the center of load (inches);

Poisson ratio assumed as 0.5.

GargandThompson [1998] proposed regression equations for estimating the subgrade modulus from FWD

test using pavement deflection, D3 in mils (0.001 inch) measured at 1097 mm radial distance from the centre

of the loading plate. The equations are:

For conventional pavements:

Log ERi= 1.51-0.19 D3 +0.27 log (D3) (2.17 a)

For full depth AC pavements:

Log ERi = 24.7-5.41 D3 +0.31 (D3) (2.17 b)

WhereERi= sub grade modulus ( ksi)

26

Roque et al, [1998] presented the following equation for the estimation of subgrade modulus based on the

deflections measured using a dual loading FWD system.

MR(ksi)=36.334(DX/60)-1.015

(2.18)

WhereDx/60 = FWD deflection (mils) measured at 60 inches radial distance from the center

of the dual plates.

Molenaar and Van Gurp [1982] developed the following equation to predict subgrade soil modulus from the

FWD deflections.

Esub (MPa) =6.614 x 10-3

x d2-1.00915

(2.19)

Where d2 = FWD deflection (in metres) measured at a radial distance of 2000 mm.

Wimsatt [1999] developed a regression model given as

Esub(MPa)= (2.20)

Where W7 = FWD deflection (mm) measured at a distance of 1828.8 mm from the center of

the load plate;

P= FWD load level (N)

Choubane and McNamara [2000] proposed the following empirical equation for predicting embankment

subgrade modulus from FWD deflection data.

ESFWD =0.03764 (P/dr) 0.898

(2.21)

where ESFWD = predicted embankment modulus based on FWD data (psi);

P= applied load (lbs);

dr = Deflection measured at a radial distance of 1097 mm.

27

Alexander et al, (1989) proposed an equation for evaluating sub grade modulus from the deflection (mils)

measured at a radial distance of 1830 mm (D72) from the centre of the loading plate for an applied load of

111206 N.

Es (psi) =59304.82 (D72) -0.98737

(2.22)

2.3.4Effect of temperature on bituminous layer

Properties of bituminous mixes vary with temperature. Modulus values determined at different temperatures

are normally adjusted to correspond to a standard temperature for design of pavements and overlays.

Different temperature adjustment factors and equations were given by various researchers for adjusting the

modulus and or deflections for temperature.

Ullidtz and Peattie[1982] utilized the deflection data from AASHO road test and the SHELL procedure for

estimation of mix stiffness and developed the following equation for comparing the moduli obtained at two

different temperatures.

ET1/ET2= (2.6277-1.38log10T1)/ (2.6277-1.38log10T2) (2.23)

Where ET1, ET2 = moduli of bituminous mix at T1 and T2 temperatures (0 C) respectively

Rada et al [1988] gave the following expression for modeling the variation of stiffness with temperature.

ETI/ET2=103.245

X1O-4

(T11.798

-T21.798

) (2.24)

2.4Traffic Loading Effect

Traffic loading is considered as the primary factor that affects both pavement design and performance.

Traffic loading characteristics include traffic volume, axle load, axle configuration, repletion of axle load,

tyre pressure, and vehicle speed. The traffic loading in pavement design is well formulated and investigated

(Wijk et al. 1998).

According to AASHTO (1993), pavement distress propagation is associated with continuous traffic growth.

The formulation of distress types leads to a failure in one the pavement components. AASHTO pavement

design procedure requires traffic evaluation for both design and rehabilitation. Therefore, the accuracy of

traffic volumes and weight is very important.

28

The rate of growth of traffic is determined from past trends or on the basis of growth of other sectors of the

economy (e.g growth of GNP, agricultural output, motor vehicle, diesel consumption)

The rate in Kenya on national highways varies from 8 to 15% per annum is commonly adopted. The

equation used for calculating the cumulative number of standard axles is,

Ns=(365A(1+r)n-1)/ r

Where Ns=cumulative number of standard axles to be catered for in the design

A=Initial traffic (commercial vpd) duly modified to account for lane distribution

r=Annual growth rate of commercial traffic

n= Design life in years

A study by Brozze and others (Brozee et al. 2004), the new Mechanistic-Empirical Pavement Design Guide

(MEPDG) requires comprehensive traffic inputs to predict pavement performance.

There are many reasons for collecting traffic data and many different types of information that can be

collected. Types of survey include surveys to determine vehicle speeds, peak hourly traffic flow, total traffic

flow, and traffic flow separated into different vehicle types (called classified traffic count).

Summary of Literature Review Findings

In summary, findings of the literature review are:

Most evaluation of pavement condition methods are based on the assessment of surface

features, as a surrogate measure of friction.

Some have attempted to correlate findings obtained from different methods, but limited

correlations could be found. The large number of methods and practices used makes the task

of finding a universal correlation unlikely successful. To complicate matters, some methods

are also based on subjective assessments.

The North Dakota study (Johnson and Cation 1992) contains a wealth of information for

assessing pavement conditions, including overall distress, structural and roughness and

performance curves.The research investigated the use of linear regression analysis, the

29

AASHTO power function, and non-linear analysis. However the method approach assumes

that pavements with the same grouping will perform similarly throughout their lives. It also

assumes that the temperature will be constant across all the 42 surveyed roads.

Some have attempted to correlate findings obtained from different methods, but limited

correlations could be found. The large number of methods and practices used makes the task

of finding a universal correlation unlikely successful. To complicate matters, some methods

are also based on subjective assessments.

This literature review has demonstrated the need to carry out a comprehensive pavement evaluation based on

overall distress, traffic volume, structural adequacy and roughness.

30

CHAPTER THREE

3.0Methodology

3.1Functional Evaluation Methodology

3.1.1Distress Condition Survey

Existing levels of distress are a very important measurement of pavement sections requirements.

This information is added to roughness data measured with Rod &Level and the Profilometer.

There are different types of deterioration and each type has different degrees of severity.

Every distress condition is the result of one or more factors, which when known give a very good

diagnosis of the pavement‟s “weaknesses”. Thus, a detailed distress survey of the pavement is one

of the steps necessary to establish pavement condition. In this research, the condition survey of the

pavement consisted of detecting, recording and quantifying the distress conditions that each section

had at the moment of conducting the study.

Equipment which was used includes;

Crack width gauge

Distance measurer

2metre straight edge and wedge

Surface condition forms

A detailed distress survey was conducted on a section of Isiolo Merille River Road and

observations in terms of distress type, severity and location were recorded.

3.1.2Roughness field test

Roughness measurements were carried out on 16th

February, 2012 using response type roughness

equipment and in accordance with ASTM E1448 / E1448M - 09 the Standard Practices for

Calibration of Systems used for Measuring Vehicular Response to Pavement Roughness

31

Figure 2.RTRRMS fitted vehicle.

3.3Structural Evaluation Methodology

The methodology of structural analysis consists of:

The collection of some principal data on a section IsioloMerille River Road which

include; traffic data, FWD‟s deflection data, pavement thickness data and the

pavement temperature data.

3.3.1Traffic count Methodology

Equipments

Survey sheets

Clipboards and pencils

Alarm clock(useful to mark the end of each hour and denote shift change

Vehicles were classified as shown below.

Motocycle&TukTuk

Cars

Pick ups,4*4

Matatus and minibuses

Large buses

Light good vehicles

Medium good vehicles

Heavy good vehicles

Articulated trucks

32

Vehicles were counted and recorded as per the classification shown above in both directions for a

period of 7days.On each day counting started at 0600hrs and ends at 1800hrs, at 1hr interval.

3.3.2Field FWD Deflection measurement

Deflection measurements were carried out on 16th

February, 2012 using the Falling Weight

Deflectometer (FWD) with 14 geophone sensors. (In the report, data on 9 geophone sensors is

reported).

The test was done in accordance with ASTM D4694 – 09; Standard Test Method for Deflections

with a Falling-Weight-Type Impulse Load Device.

Measurements were taken with a test plate of 150 mm radius and at intervals of approximately 100

m on each lane at an offset of about 0.6m (outer wheel path) from the edge of the carriageway.

The deflections are measured at the centre of the test plate and at various distances away from the

load and in this case at nine (9) consecutive geophone points of 0, 20, 30, 60, 90, 120, 150, 180, and

210 cm.

The temperature of the air, surface and pavement were also recorded.

After the FWD tests, the pavement surface was cored to measure the surface layer thickness at the same

FWD tested spots. To measure the strength characteristics of base, sub base and sub grade layers, the

Dynamic Cone Penetration (DCP) test (ASTM, 2009) was conducted immediately after at the cored spot for

140 centimeters depth from the surface.

(Summary of research methodology is shown in fig 3.2)

33

Figure 3.Flow chart of Research

START

EVALUATION OF FUNCTIONAL CONDITION EVALUATION OF STRUCTURAL

CONDITION

DATA COLLECTION DATA COLLECTION

DISTRESS SURVEYDATA ROUGHNESSDATA TRAFFIC DATA DEFLECTION DATA PAVEMENT

THICKNESS DATA

DENSITY CALCULATION ANALYSIS OF IRIDATA STRUCTURAL ANALYSIS

DENSITY ANALYSIS PSI CALCULATION

FUNCTIONAL CONDITION FUNCTIONAL CONDITION

COMPARISON OF FUNCTIONAL

CONDITION

COMPOUND ANALYSIS

FUNCTIONAL-STRUCTURAL

CONCLUSION

FINISH

FUNCTIONAL ANALYSIS

STRUCTURAL

ANALYSIS

34

3.4Error Analysis

3.4.1Common sources of errors in FWD testing

3.4.1.1Seating Error

This error is caused by load plate and sensors not in “stable” contact with pavement due to debris.

To overcome this error, more than one seating drops before the recorded data.

3.4.1.2Random Error

The common cause of this error is analog to digital conversion in FWD recording of deflections.

Typically this error is not more than ±2microns.

To correct the above errors, all deflection data were also normalized to a standard pressure of 707

KPa which is equivalent to load of 5 KN (10 KN axle) on a wheel assembly with 150 mm radius

3.4.2Common sources of errors in Roughness measurement

3.4.2.1CalibrationError.

The RTRRMS calibration may not cover all of the variables which affect the measurements. This

will mainly be manifested in the form of systematic errors in the RTRRMS.

To minimize this type of error the RTRRMS was regularly calibrated against a rod and level

survey. This calibration was carried out before the survey and checked on control sites during the

survey period to ensure that RTRRMS remains with calibration.

3.4.2.2Reproducibility Error

Two different instruments may rank several roads in different order by roughness.

To reduce reproducibility errors the RTRRMS was operated at a speed of about 50km/h.

3.4.2.3Repeatability Error

This is influenced by;(1)The accuracy of the instrumentation(2)The random locations of specific

points along the wheel path where the measurements are taken.(3)the partly random selection of the

wheel path..

35

3.4.3Common sources of errors in traffic counting

They include

Counting on different days whereby travel patterns vary from day to day.

Counting errors. This can be due to parallax effect. Systematic errors may occur due to factors such

as incorrect sampling or insufficient control of survey procedures.

3.4.3.1Reconciliation of traffic counts

The measurement errors assess the accuracy of the enumerator counts. This equivalent to comparing two or

more counts of the same thing at the same time by different people, so as to see how close they are in

agreement.

The traffic Appraisal Manual gives the following figures;

Type Error estimate Comments

Cars ±10%

Buses ±5% It is likely that buses will be counted with more accuracy than cars,

since they are more visible on the road.

Pedestrians

and cyclists

±10%

Motorcycles ±15% Motorcycles can be inconspicuous in the traffic. They don‟t always

keep to the designated lanes and easily speed along the carriageway

or weave between lanes.

Table 5.Showing counting error estimates for different traffic types.

Source: Highway Appraisal Manual

36

3.4.3.2Daily Variation of traffic errors

Figure 4.Errors in ADT estimates from random counts of varying duration.

According to Howe,1972, a survey of seven consecutive days appears to be an optimum length and surveys

beyond this length do not increase the accuracy very rapidly . It can also be seen that the likely accuracy of

even a week‟s survey is in the range ±16% for traffic flows greater than 1000 vehicles per day, increasing to

±36% for traffic less than 75 vehicles per day. These large potential errors are caused by monthly and

seasonal variations.

In this report, traffic data was collected for a period of 7 days with an error of about ±16% as illustrated in

the graph.

0

10

20

30

40

50

60

70

0 5 10 15 20 25 30 35 40 45

ERR

OR

(±P

ERC

ENT)

Duration in days

<75v/day

>1001v/day 601-1000v/day

76-200v/day

201-600v/day

Source;Road Note 40

37

CHAPTER FOUR

4.0DATA PRESENTATION

4.1FWD’s Deflection Data The deflections were measured at the centre of the test plate and at various distances away from the load and

in this case at nine (9) consecutive geophone points of 0, 20, 30, 60, 90, 120, 150, 180, and 210 cm.At each

distance, corresponding deflection was recorded as shown below. These FWD‟s deflection data was used in

structural analysis to obtain stiffness moduli of each pavement layer.

From figure, it can be seen that deflection 1 is the highest at different chainage while deflection 9 is the

lowest.

Figure 5.Showing deflection on a section of Isiolo Merile Road.

0

500

1000

1500

2000

2500

1

12

23

34

45

56

67

78

89

10

0

11

1

12

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

21

0

22

1

23

2

24

3

25

4

26

5

27

6

28

7

29

8

de

fle

ctio

n (

×0.0

01

mm

)

Chainages in m(×500)

Deflection on a section of Isiolo Merile Road

d1

d2

d3

d4

d5

d6

d7

d8

d9

38

4.2 Distress Survey Data A detailed visual condition survey was undertaken for both lanes in each direction of travel. The survey was

generally done in accordance with ASTM D6433, “Standard Practice for Roads and parking Lots Pavement

Condition Index Surveys”. Based on the survey data, the most prevalent pavement distresses and those most

likely to influence the pavement are shown in appendix A.

Type, description, severity and location of the observed defects were recorded for a stretch of 20km from

Isiolo town. An additional observation was also recorded at km 59+200 for comparison. The types of defects

which were predominant include longitudinal meandering cracks, longitudinal wheel path cracks, traverse

cracks, pavement edge cracks, raveling and rutting. They were described base on the frequency of their

occurrence, severity and location i.e. on the carriageway or shoulder.

The type of distress tells us what type of damage has developed; the severity tells how bad the damage is;

and description gives us the extent of the type and severity of damage that is present. All three of these

factors were recorded to get a full picture of the damage that has developed on the pavement surface and

were used to determine the type and timing of maintenance, rehabilitation, and reconstruction.

Generally, the low severity level identifies that the distress type has appeared but that it is not causing a

problem at this point. A high or heavy severity level generally indicates that the distress is so bad that

maintenance is needed immediately or should have already been performed. The medium or moderate

severity level generally indicates that the distress has progressed to the point where the pavement needs

attention or it will become a problem shortly. This provides adequate information to define the level of

damage that is present and to help identify when treatments should be applied. It also gives adequate

information needed to calculate a condition index that can be used to project future condition.

When the distress type and severity have been determined, the percentage of area was estimated. For both

longitudinal and transverse cracking, the score depends on whether the cracks are sealed, partially sealed, or

not sealed. The overall score for the segment is the sum of all its scores for individual defects.

The damage quantities are estimates of the percentage of the entire section affected and are generally in

categories such as:

Low- the total section length affected is less than 10% of the section length

Moderate- the total section length affected is between 10% and 30% of the section length

High- the total section length affected is more than 30% of the section length

39

4.3Roughness Data Roughness measurements were carried out using response type roughness equipment and in accordance with

ASTM E1448 / E1448M - 09 the Standard Practices for Calibration of Systems used for Measuring

Vehicular Response to Pavement Roughness.

The ride quality of each pavement section was recorded using two bump integrators attached to the

vehicle, one in each wheel path. The output from the bump integrators is calibrated to produce

International Roughness Index (IRI) values for each 100 metre sample unit as shown in appendix c.

Figure 6.Showing correlation between NAASRA and speed.

Figure 7.Showing Correlation between IRI and speed

0

100

200

300

400

500

600

700

1 7

13

19

25

31

37

43

49

55

61

67

73

79

85

91

97

10

3

10

9

11

5

12

1

12

7

13

3

13

9

14

5

Correlation between NAASRA and Speed

NAASRA

Speed

40

From figure, it can be noted that the higher the speed, the lower the NAASRA and vice versa.

Similarly, the higher the IRI value, the lower the speed and vice versa.

0

10

20

30

40

50

60

70

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101106111116121126131136141146

Correlation between IRI and Speed

IRI Speed

41

4.4Traffic Survey Data

The traffic survey results were collected to assist in obtaining the Average Daily Traffic and the

axles along the road and also to assist in the back-analysis of the FWD deflection data. Traffic data

collected in the field are attached in the Appendix F.

The figures below shows the general traffic count for 5days.

Figure 8.Showing traffic count on Merile barrier on different days.

Figure 9.Showing traffic count on Isiolo barrier on different days

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Friday Saturday Sunday Monday Tuesday

Traf

fic

Co

un

t

Day of the week

Isiolo Barrier

Series1

0

50

100

150

200

250

Friday Saturday Sunday Monday Tuesday

Traf

fic

Co

un

t

Day of the week

Merille Barrier

Series1

42

From figure 8, it can be seen that more traffic count was recorded on Tuesday. However, traffic

count on this barrier was generally less than that of Isiolo barrier.

4.5Pavement Thickness Data

Regarding the results of the test-pit survey, the pavement thickness on Isiolo-Merile consists of

subgrade, sub base, base and surfacing as shown in appendix D.

The pavement thickness layers were not uniform for the entire section. At KM 5+000LHS,

surfacing is 50mm, base is 180mm, sub base is 380mm and subgrade is 530mm.

At KM8+000RHS, surfacing is 50mm, base is 180mm, sub base is 340mm and subgrade is 490mm.

43

CHAPTER FIVE

5.0 DATA ANALYSIS AND DISCUSSION

5.1Roughness Data Analysis 5.1.2Correlation between PSI and IRI

Various correlations have been developed between PSI and IRI. In this report, we adopted the correlation

developed by Sayers,et al.(1986) expressed as follows: Calculated PSI for different measured IRI are shown

on appendix E table 14.

PSI=5×e(-0.18×RI)

(5.1)

Where: PSI=Present Serviceability Index

IRI=International Roughness Index

Average PSI=Summation of all PSI calculated/Total number of samples (5.2)

=436.193/150

=2.91~3 (Good)

Average IRI=Summation of all IRI/Total number of sample

=586.3/150

=3.9 (5.3)

Calculated PSI from Average=5×e(-0.18×IRI)

=5×e(-0.18×3.9)

=2.48 (5.4)

%Error between calculated PSI and Average PSI

= (3.0-2.48)/3.0 ×100%

=52%

According to Sayers,et al(1986) a pavement with pavement serviceability index (PSI) ranging between 3 and

4 is considered in GOOD condition. However, this approach of rating pavement has its limitation in that it

does not cater for parameters such as pavement inadequacy and edge failure.

According to Dewan, 2012, he suggested that international roughness index (IRI) threshold which is less

than 95in/mi is considered to be GOOD in terms of ride quality while a threshold less than 170in/mi is

considered to be ACCEPTABLE in terms of ride quality. In this study we obtain an average IRI which is

within acceptable limit.

44

5.2Traffic Data Analysis

Table 6.Traffic volume (ADT)-MERILE BARRIER

Station:BARRIER-MERILE TRAFFIC VOLUME(ADT)-MERILLE

BARRIER

Vehicle

Category

Frida

y

Saturda

y

Sunda

y

Monda

y

Tuesda

y

Traffi

c

Directio

n

AD

T

AD

T

M/Cycles

&

TukTuk

12 5 16 16 19 44% Nbound 31 14

13 22 22 12 16 56% Sbound 17

Cars 3 2 1 2 3 44% Nbound 5 2

5 1 2 5 1 56% Sbound 3

Pick-ups 67 24 42 43 36 56% Nbound 75 42

22 42 38 21 41 44% Sbound 33

Minibuses

&matatus

8 6 6 2 9 76% Nbound 8 6

1 3 2 1 3 24% Sbound 2

Large

Buses

5 8 7 7 5 65% Nbound 10 6

4 4 1 4 4 35% Sbound 3

LGV(Ligh

t

Trucks)

1 2 3 2 7 31% Nbound 10 3

6 7 6 6 8 69% Sbound 7

MGV

(Medium)

5 9 10 0 14 46% Nbound 17 8

8 8 4 7 18 54% Sbound 9

HGV

(3axles)

2 2 13 4 5 65% Nbound 8 5

2 2 6 2 2 35% Sbound 3

Articulate

d

Trucks

5 1 4 33 4 51% Nbound 18 9

11 8 3 11 12 49% Sbound 9

Tractors 3 2 2 0 0 30% Nbound 5 2

10 1 1 3 1 70% Sbound 3

Totals 193 159 189 181 208 186

Table 7.Traffic volume (ADT)-ISIOLO BARRIER

Station:BARRIER-ISIOLO TRAFFIC VOLUME(ADT)-ISIOLO BARRIER

Vehicle

Category

Frida

y

Saturda

y

Sunda

y

Monda

y

Tuesda

y

Traffi

c

Directio

n

AD

T

AD

T

M/Cycles

&

499 437 329 417 482 50% Nbound 869 433

493 557 522 54 555 50% Sbound 436

N-BOUND Merile Isiolo S-BOUND Isiolo Merile

N-BOUND Merile Isiolo S-BOUND Isiolo Merile

45

TukTuk

Cars 152 78 76 61 89 46% Nbound 198 91

108 111 123 91 103 54% Sbound 107

Pick-ups 151 146 127 130 158 51% Nbound 280 142

175 120 95 140 160 49% Sbound 138

Minibuses

&matatus

71 77 43 81 72 54% Nbound 127 69

72 76 48 83 11 46% Sbound 58

Large

Buses

10 13 13 8 12 51% Nbound 22 11

9 14 10 11 10 49% Sbound 11

LGV(Ligh

t

Trucks)

37 24 13 25 25 63% Nbound 40 25

10 22 10 13 18 37% Sbound 15

MGV

(Medium)

17 20 17 24 29 43% Nbound 50 21

28 30 20 25 40 57% Sbound 29

HGV

(3axles)

8 3 2 5 4 38% Nbound 11 4

17 4 2 10 3 62% Sbound 7

Articulate

d

Trucks

5 3 0 1 7 36% Nbound 9 3

7 3 6 9 3 64% Sbound 6

Tractors 0 3 0 0 1 40% Nbound 2 1

0 2 0 3 1 60% Sbound 1

Totals 1869 1743 1456 1191 1783 1606

Table 8.Baseline ADT Isiolo Merile

BASELINE ADT on Isiolo – Merile(A2)Project Road

Station

Name

Directio

n

M/c

ycles

Car

s

Pick

-

Ups

4*4

Mata Buse

s

LG

V

MGV HG

V

Art

i

Trac

tors

Totals

BARRI

ER

Nbound 433 91 142 69 11 25 21 4 3 1 800 1608

Sbound 436 107 138 58 11 15 29 7 6 1 808

MERIL

E

Nbound 14 2 42 6 6 3 8 5 7 1 94 183

Sbound 17 3 33 2 3 7 9 3 9 3 89

TOTAL Nbound 447 93 184 75 17 28 29 9 10 2 894 1791

Sbound 453 110 171 60 14 22 38 10 15 4 897

46

ESA=ADT×365×(r+1)n-1)/r

Where ESA=Equivalent standard axle

ADT=Average Daily Traffic

R=growth rate (assumed to be 7.5%)

N=Design life (20years)

Motorcycles and cars causes negligible damage on the road hence are not considered in the

calculation of ESA.

Thus ADT used in the calculation=1791-1103

=688

ESA=365×0.5×688×((0.075+1)20

-1)/0.075

=5.4msa

From error analysis in chapter three, ADT ranges ±22% since the traffic flow lies between 601-

1000.

Therefore optimistic traffic=122/100×688

=840vpd and,

Pessimistic traffic =78/100×688

=537vpd

From the calculated cumulative standard axle, it is worth noting that the forecasted cumulative standard axle

is not exceeded .Therefore traffic loading is not the cause of any observed surface distress.

47

Figure 10.Showing error limits on traffic volume analysis.

5.3Deflection Data Analysis The FWD measured deflections are used to back-calculate the elastic modulus of the pavement layers using

Rosy design software. This design software uses linear elastic theory to back calculate moduli from FWD

data and residual life.

The calculation was based on a four layer model consisting of asphaltic concrete, base course, sub base and

sub grade layers. The data points represent the average of the resilient moduli calculated along each of the

measurements points.

Below is key parameters derived from the FWD deflection data and back analysis using Rosy software.

Table 9.FWD Back-analysis Results of key parameters.

Parameter Value Condition

Average asphalt stiffness 3753Mpa Acceptable

Average base stiffness 338Mpa Acceptable

Average sub base stiffness 338Mpa Acceptable

Average Subgrade stiffness 338Mpa Acceptable

Residual Life 15years Acceptable

0

100

200

300

400

500

600

700

800

900

pessimistic actual optimistic

Traf

fic

volu

me

48

5.4Surface Defect Analysis Analysis of surface distress was based on Haas et al.1994.The extent of each pavement distress of the road

section was obtained by averaging the density severity score for each distress type.

In this analysis the density calculated was based on the total length of distress over a single length of

roadway lanes times two.

Table 10.Severity and density estimates of surface distress types on a section of Isiolo Merile

Road.

Distress Type Density

Value Description

Longitudinal Wheel Path Cracking 8.0% intermittent

Longitudinal Joint Cracking 3.3% few

Pavement Edge Cracking 6.8% intermittent

Traverse Cracking 4.8% few

Meandering Longitudinal Cracking 1.6% few

Crocodile cracking 0% None

Rutting 3.5% Few

Shoving 0% Nome

Distortion 0% None

Bleeding 0% None

Potholes 0% None

Ravelling 9.6% Intermittent

Overall Rating 37.6% Good

5.5Discussion The main objective of this study was to evaluate the condition of a section of Isiolo- Merille River

Road(A2).The existing condition data was then analysed to establish the causes of distresses manifested on

the surface and there after recommend on the best rehabilitation method to employ.

In this report different parameters of pavement evaluation were keenly investigated. These parameters

include:

Pavement Roughness

Pavement structural adequacy

Pavement Surface Defects

Traffic Loading

However, we cannot conclude fully that the cause of any observed pavement distress is this or that since

some of the adopted methods were subjective.

5.5.1Pavement Roughness

Pavement roughness reflects the travelling public‟s perception of the quality of the highways and is related to

vehicle operation costs.

49

As shown in table 14, the section generally shows a GOOD road surface (according to Sayers et al, 1986)

with an average PSI of about 3 which is within acceptable limit of a new pavement. However, it was

observed that the calculated PSI in equation 5.4 showed a FAIR condition with a value much lower than the

average PSI obtained in equation 5.2.This variation might have been attributed to by existence of speed

bumps.

It can be noted that as the roughness in terms of NAASRA increases, speed decreases drastically.

The pavement section can be considered smooth with minimal imperfections which bear no significant effect

to the performance of the pavement.

5.5.2Pavement Structural Adequacy

Pavement structural capacity is an engineering concept to indicate the ability of the pavement to carry

designed traffic loads adequately. From a summary of key parameters derived from the FWD deflection data

and back analysis using Rosy software, the stiffness moduli for all pavement layers were obtained to be

within the acceptable range. This means that the surface distress observed might not be as a result of

structural inadequacy.

5.5.3Pavement Surface Defects

Based on the visual condition survey, the primary distresses were;

Longitudinal Wheel Path Cracking

Longitudinal Joint Cracking

Pavement Edge Cracking

Traverse Cracking

Meandering Longitudinal Cracking

Rutting

Ravelling

The study section along Isiolo Merile River Road is manifested by intermittent longitudinal wheel path

cracking, few longitudinal joint cracking, intermittent pavement edge cracking, few traverse cracking, few

meandering longitudinal cracking, few rutting and intermittent cracking.

According to Road Note 40, the potential cause of longitudinal wheel path cracking as shown in figure 11

might be unstable base or inadequate bonding during construction stage.

50

Figure 11.Showing longitudinal wheel path crack.

Potential causes of traverse cracking might be due to contraction and shrinkage of the surface course

attributed by differential temperatures of the layers.

Substantial difference in densities on either side of the longitudinal joint (density gradient across the joint)

might be the cause of longitudinal joint cracking. The reason for this difference in densities is that when the

first lane is paved, one of its edges is unconfined, leading to a lower density after compaction. When the

adjoining lane is paved, the edge of the first pass confines the new mix and prevents it from spreading. This

results in higher density on the second pass at the center of the road.

Potential cause of rutting might be insufficient compaction of pavement layers during construction. If the

layers are not compacted enough initially, pavement layers may continue to densify under continual traffic

loading.

51

Figure 12.Showing pavement edge crack.

5.5.4Traffic Loading

Traffic loading is normally considered in terms of repetitions of axle load and during the design period the

pavement is subjected to axle loads that vary in magnitude, frequency and configuration.

Survey on traffic loading was essential to ascertain whether the pavement structure is adequate enough to

withstand traffic loading on it.However, it was observed through traffic data analysis that the surface distress

noted on the road section are not as a result of traffic loading.

52

CHAPTER SIX

6.0CONCLUSION AND RECOMMENDATIONS

6.1 Pavement Roughness The study shows that the road is smooth with minimal roughness and estimated overall pavement

serviceability index condition as GOOD.

6.2Pavement structural adequacy The measured deflections and the back-calculated structured moduli for various pavement layers are within

acceptable ranges. The pavement structure can be considered adequate to sustain the anticipated traffic

loading. There are no potential structural failures and deterioration. However in order to achieve this and

prolong the residual life, the identified surface distresses must be addressed.

6.3Pavement surface distress The study has demonstrated through field observations and rating results that the road surface exhibits some

surface distresses but can generally be considered GOOD. The dominant surface distresses observed,

comprise of longitudinal wheel path cracks, edge cracking /breaking, traverse cracking, ravelling and rutting

have varied severity and density level at various sections.

The potential causes of the above surface distresses might be attributed to by inadequate bonding during

construction or by insufficient shoulder support or poor compaction and poor adhesion of aggregates due

insufficient asphalt content.

6.4Traffic Loading The traffic survey conducted on the section of this road and the subsequent calculation of cumulative

standard axle has clearly demonstrated that surface distresses are not attributed by traffic loading.

6.5Recommendation

Highway pavements once constructed will not last forever. After a time, signs of wear will appear.

Therefore, the pavement must be resurfaced or rehabilitated at periodic intervals to add life and

keep them in good condition. For bituminous roads, maintenance can be either minor or major.

The types of pavement maintenance to employ depend upon the pavement indices calculated from

data collected on the pavement. These indices are estimated by considering parameters like

pavement distresses, structural adequacy, traffic loading, pavement roughness and pavement age.

In this report it was found that the pavement condition is generally GOOD i.e. pavement structure is

adequate, traffic volume and loading is within the growth limit and also ride quality being within

the acceptable limits. However, the surface imperfection needs to be addressed as part of the

maintenance work.

53

The following in table 11 were recommended as part of the intervention on the section of Isiolo

Merile River Road.

Table 11.Recommended intervention.

Defects Recommended Interventions

Longitudinal cracks Sealing to reduce moisture penetration and prevent further sub

grade weakening but if the longitudinal cracks progress to wheel

path or pavement edge become frequent, an overlay is warranted to

strengthen the pavement.

Traverse cracks Sealing the crack to prevent ingress of water which can deteriorate

the sub grade but if the cracks progress, double surface dressing

will be needed.

Raveling Seal coat is required as part of the maintenance work.

Rutting. Milling of the old surface should be done and the resurfacing if

rutting is severe to strengthen the pavement.

Broken edges Stone chipping of the embankment slopes to prevent further loss of

materials.

54

REFERENCES 1. F.J Gichaga and N.A. Parker 1989: Essentials of Highway Engineering Macmillan Publishers.

2. Sayers MW, Gillespie TD and Queroz C AV (1986a).The international road roughness

experiment: Establishing correlation and calibration standard for measurements. Technical paper

No.46. World Bank, Washington DC.

3. AASHTO,(1993),AASHTO(guide for design of pavement structures),The American Association

of State Highway Transportation Officials, Washington DC.

4.Watanatada T,Harral C G,Patterson W D O ,Dhareshwar A M,Bhandari A and Tsunokawa

K (1987).The highway design and maintenance standards model. Highway Design and standards

series. The John Hopkins University Press, Maryland.

5. Paterson W D O (1987).Road deterioration and maintenance effects: models for planning and

management. Highway Design and maintenance series. The John Hopkins University Press, Baltimore

Maryland.

6.Livneh, M., and I.Ishai.Pavement and Material Evaluation by a Dynamic Cone Penetrometer

(1987),proc., Sixth International Conference on the structural design of asphalt pavement,Vol 1,Ann

Arbor,Michigan,pp 665-674.

7. Ullidtz,P. and Coetzee, N.F.(1995).Analytical procedures in Non –destructive, Transportation Research

Board 1482:61-66.

8. Martin,T., and Roberts, J; 1996. Recommendations for monitoring pavement performance. ARRB

Transport Research Ltd, Melbourne.

9. Ministry of Transport and Infrastructure,2012.

10.www.inftra.gov.ab.ca.

55

APPENDICES

APPENDIX A

A.SURFACE DISTRESS DEFECTS

Table 12.Types of observed defects, severity and their location.

56

CHAINA

GE

DEFFECTS

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

0+000 longitudi

nal

wheel

path

cracking

None low none Few low carriageway single

unsealed

cracks

with no

spalling

longitudi

nal joint

cracking

None low none Few low shoulder/carriag

eway

rutting Few low carriageway Few low carriageway

1+000 longitudi

nal

wheel

path

cracking

Few Moderate shoulder/carriag

eway

Few moderate shoulder/carriag

eway

multiple

severe

spalling

cracks

longitudi

nal joint

cracking

Frequent Moderate shoulder throughout high shoulder

pavemen

t edge

cracking

Few low shoulder/carriag

eway

Intermittent moderate shoulder

longitudi

nal

meanderi

ng

cracking

Few low shoulder/carriag

eway

Few moderate shoulder/carriag

eway

rutting Few low carriageway None low none

2+000 longitudi

nal

wheel

path

cracking

Few low carriageway Few low carriageway multiple

moderate

spaling

cracks

longitudi

nal joint

cracking

Throughout Moderate shoulder/carriag

eway

throughout moderate shoulder/carriag

eway

pavemen

t edge

cracking

frequent high shoulder/carriag

eway

Frequent high shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Intermittent Moderate shoulder/carriag

eway

Frequent moderate shoulder/carriag

eway

transvers

e

cracking

Throughout high shoulder/carriag

eway

throughout high shoulder/carriag

eway

rutting

present

Few low carriageway Few low carriageway

CHAINA

GE

DEFFECTS

57

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

3+000 longitudi

nal

wheel

path

cracking

Few low shoulder/carriag

eway

Few moderate carriageway unsealed

cracks

longitudi

nal joint

cracking

Throughout low shoulder/carriag

eway

Few low shoulder/carriag

eway

pavemen

t edge

cracking

Frequent Moderate shoulder/carriag

eway

Few low shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Frequent Moderate shoulder Intermittent moderate shoulder

transvers

e

cracking

Throughout Moderate shoulder/carriag

eway

Frequent moderate shoulder/carriag

eway

rutting

present

Few low carriageway Few low carriageway

raveling

present

Throughout low shoulder throughout moderate shoulder

4+000 longitudi

nal

wheel

path

cracking

Few low carriageway Intermittent moderate carriageway multiple

unsealed

cracks

with no

spalling

longitudi

nal joint

cracking

Frequent Moderate shoulder Extensive moderate shoulder/carriag

eway

pavemen

t edge

cracking

Few Moderate shoulder/carriag

eway

Frequent moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Intermittent Moderate shoulder Frequent moderate shoulder

transvers

e

cracking

Extensive Moderate shoulder Intermittent moderate shoulder/carriag

eway

rutting

present

Few low carriageway Few low carriageway

ravelling

present

Throughout Moderate shoulder throughout moderate shoulder

5+000 longitudi

nal joint

cracking

Intermittent moderate shoulder Few moderate shoulder unsealed

cracks

CHAINA

GE

DEFFECTS

58

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

pavemen

t edge

cracking

Intermittent

moderate

shoulder

Intermittent

moderate

shoulder

longitudi

nal

meanderi

ng

cracking

Few low shoulder Intermittent moderate shoulder

transvers

e

cracking

Intermittent moderate shoulder/carriag

eway

Frequent moderate shoulder

rutting

present

Few low carriageway Few low carriageway

ravelling

present

Throughout moderate shoulder extensive low shoulder

6+000 longitudi

nal joint

cracking

Few low carriageway few low shoulder single

unsealed

cracks

transvers

e

cracking

Intermittent moderate shoulder intermitent moderate shoulder

rutting

present

Few low carriageway few low carriageway

ravelling

present

Throughout high shoulder extensive low shoulder

7+000 longitudi

nal

wheelpat

h

cracking

Few moderate shoulder/carriag

eway

few moderate shoulder/carriag

eway

single

unsealed

cracks

with no

spalling

longitudi

nal joint

cracking

Few moderate shoulder few moderate shoulder/carriag

eway

pavemen

t edge

cracking

Intermittent moderate shoulder/carriag

eway

few moderate shoulder

longitudi

nal

meanderi

ng

cracking

Frequent low shoulder/carriag

eway

few moderate shoulder/carriag

eway

transvers

e

cracking

Intermittent low shoulder intermittent moderate shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

ravelling

present

Throughout moderate shoulder extensive low shoulder

CHAINA

GE

DEFFECTS

59

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

8+000 longitudi

nal

wheel

path

cracking

Intermittent moderate carriageway few moderate carriageway cracks

sealed

longitudi

nal joint

cracking

Few moderate carriageway few moderate carriageway

pavemen

t edge

cracking

Few moderate shoulder/carriag

eway

intermittent low shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Frequent moderate shoulder/carriag

eway

intermittent moderate shoulder/carriag

eway

transvers

e

cracking

Throughout moderate shoulder/carriag

eway

extensive moderate shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

raveling

present

Throughout moderate shoulder/carriag

eway

extensive moderate shoulder/carriag

eway

9+000 longitudi

nal joint

cracking

Intermittent moderate shoulder/carriag

eway

few moderate carriageway single

sealed

cracks

pavemen

t edge

cracking

Few moderate shoulder/carriag

eway

intermittent moderate shoulder

longitudi

nal

meanderi

ng

cracking

Few low shoulder/carriag

eway

few moderate shoulder

transvers

e

cracking

Intermittent moderate shoulder intermittent moderate shoulder/carriag

eway

rutting

present

Intermittent moderate carriageway few low carriageway

raveling

present

Throughout moderate shoulder frequent moderate shoulder/carriag

eway

10+000 longitudi

nal

wheel

path

cracking

Few moderate shoulder/carriag

eway

few moderate carriageway

longitudi

nal joint

cracking

Throughout moderate shoulder frequent low shoulder/carriag

eway

cracks

unsealed

pavemen

t edge

cracking

Few moderate shoulder intermittent moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng crack

Few low shoulder/carriag

eway

few moderate shoulder

CHAINA

GE

DEFFECTS

60

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

transvers

e

cracking

Extensive moderate shoulder/carriag

eway

intermittent moderate shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

raveling

present

Throughout high shoulder/carriag

eway

extensive moderate shoulder

11+000 longitudi

nal

wheel

path

cracking

Frequent moderate shoulder/carriag

eway

few moderate shoulder/carriag

eway

few

cracks

sealed

longitudi

nal joint

cracking

Frequent moderate shoulder/carriag

eway

intermittent moderate shoulder/carriag

eway

pavemen

t edge

cracking

Few low shoulder/carriag

eway

few moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Few low carriageway few moderate shoulder/carriag

eway

transvers

e

cracking

Intermittent high shoulder/carriag

eway

frequent low shoulder/carriag

eway

rutting

present

Intermittent low carriageway few low carriageway

raveling

present

Throughout high shoulder extensive moderate shoulder/carriag

eway

12+000 longitudi

nal

wheel

path

cracking

Few low carriageway few moderate carriageway few

cracks

sealed

pavemen

t edge

cracking

Few low shoulder/carriag

eway

none low none

longitudi

nal

meanderi

ng

cracking

Frequent moderate shoulder/carriag

eway

none low none

transvers

e

cracking

Few moderate shoulder/carriag

eway

few low shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

raveling

present

Throughout moderate shoulder extensive low shoulder

13+000

longitudi

nal joint

cracking

Frequent moderate carriageway none low none few

cracks

sealed

CHAINA

DEFFECTS

61

GE

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

longitudi

nal

meanderi

ng

cracking

Frequent moderate carriageway none low none

transvers

e

cracking

Throughout moderate shoulder/carriag

eway

frequent low shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

ravelling

present

Throughout moderate shoulder extensive moderate shoulder/carriag

eway

14+000 longitudi

nal

wheel

path

cracking

Intermittent low carriageway frequent moderate carriageway cracks

unsealed

longitudi

nal joint

cracking

few low carriageway none low none

pavemen

t edge

cracking

None low none frequent moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Few moderate carriageway few moderate carriageway

transvers

e

cracking

Extensive moderate shoulder/carriag

eway

frequent moderate shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

raveling

present

Throughout moderate shoulder throughout low shoulder/carriag

eway

15+000 longitudi

nal

wheel

path

cracking

Intermittent moderate carriageway few moderate carriageway cracks

unsealed

longitudi

nal joint

cracking

Frequent moderate carriageway intermittent moderate carriageway

pavemen

t edge

cracking

Intermittent moderate shoulder/carriag

eway

few moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Frequent moderate carriageway none low none

transvers

e

cracking

Throughout moderate shoulder/carriag

eway

throughout low shoulder/carriag

eway

62

rutting

present

Few low carriageway few low carriageway

CHAINA

GE

DEFFECTS

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

raveling

present

Throughout low shoulder throughout low shoulder

potholes

present

Few low shoulder none low none

16+000 longitudi

nal

wheel

path

cracking

Throughout moderate carriageway intermittent moderate shoulder/carriag

eway

cracks

unsealed

longitudi

nal joint

cracking

Few moderate carriageway few moderate shoulder/carriag

eway

pavemen

t edge

cracking

Few moderate carriageway few moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

Frequent moderate carriageway intermittent moderate shoulder/carriag

eway

transvers

e

cracking

Frequent moderate shoulder/carriag

eway

frequent moderate shoulder/carriag

eway

rutting

present

Few low carriageway few low carriageway

ravelling

present

throughout moderate shoulder extensive low shoulder

17+000 longitudi

nal

wheel

path

cracking

few moderate carriageway few moderate carriageway most

cracks

sealed

longitudi

nal joint

cracking

intermittent moderate carriageway none low none

pavemen

t edge

cracking

few moderate shoulder extensive moderate shoulder

longitudi

nal

meanderi

ng

cracking

frequent moderate shoulder/carriag

eway

few low shoulder

transvers

e

cracking

throughout moderate shoulder/carriag

eway

extensive moderate shoulder/carriag

eway

rutting

present

few low carriageway few moderate carriageway

raveling

present

throughout moderate shoulder extensive low shoulder

18+000 longitudi

nal

wheel

path

intermittent moderate carriageway few low carriageway

63

cracking

longitudi

nal joint

cracking

frequent moderate shoulder/carriag

eway

few low shoulder most

cracks

sealed

CHAINA

GE

DEFFECTS

LHS RHS

TYPE DESCRIPTI

ON

SEVERI

TY

LOCATION DESCRIPTI

ON

SEVERI

TY

LOCATION REMAR

KS

pavemen

t edge

cracking

intermittent moderate shoulder/carriag

eway

intermittent moderate shoulder/carriag

eway

longitudi

nal

meanderi

ng

cracking

few low carriageway intermittent moderate shoulder/carriag

eway

transvers

e

cracking

intermittent moderate shoulder/carriag

eway

frequent moderate shoulder/carriag

eway

rutting

present

few low carriageway few low carriageway

raveling

present

throughout moderate shoulder throughout low shoulder

19+000 longitudi

nal joint

cracking

extensive moderate carriageway few low carriageway most

cracks

sealed

pavemen

t edge

cracking

intermittent moderate shoulder/carriag

eway

few low carriageway

longitudi

nal

meanderi

ng

cracking

intermittent moderate carriageway intermittent low shoulder/carriag

eway

transvers

e

cracking

extensive moderate shoulder/carriag

eway

few low shoulder

rutting

present

few low carriageway intermittent low shoulder/carriag

eway

raveling

present

throughout moderate shoulder/carriag

eway

extensive low shoulder

20+000 longitudi

nal

meanderi

ng

cracking

few moderate shoulder intermittent moderate carriageway most

cracks

sealed

transvers

e

cracking

throughout moderate shoulder frequent moderate shoulder/carriag

eway

raveling

present

few low carriageway few low shoulder

59+200 transvers

e

cracking

few low shoulder few low shoulder minor

cracks

raveling

present

few low shoulder extensive low shoulder

64

APPENDIX B

B.FWD DEFLECTION DATA

65

Table 13.Deflection data

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

0

Start Of

LHS 344 249 194 132 102 86 74 63 56 27.4 30.5 40.2 708

0

End Of

RHS 290 244 220 173 138 113 96 82 71 28.5 35.1 38.6 719

50 313 246 203 142 100 79 65 56 48 28.9 35.7 38.6 739

101 360 269 210 143 100 79 67 57 50 27.3 31 40.2 677

147 428 317 259 184 134 106 86 72 62 28.8 36.2 38.6 727

200 453 339 264 180 128 100 82 69 59 27.1 30.9 40.2 708

250 410 320 266 189 138 110 91 79 70 29.1 36.1 38.6 733

304 735 564 431 288 203 158 128 105 91 27.1 31.4 40.2 680

349 266 217 181 129 94 77 67 61 54 29.1 36.7 38.6 725

401 381 302 235 167 124 99 82 69 59 27 31.8 40.2 716

444 568 486 420 318 240 191 153 130 110 28.9 37 38.6 728

500 429 324 254 169 114 89 74 63 56 27.1 32.1 40.2 690

549 614 452 355 245 173 131 104 88 77 28.7 37.1 38.6 739

602 356 287 242 177 129 99 78 63 54 27.3 32.3 40.2 702

648 519 376 280 182 131 109 93 82 73 28.1 37.3 38.6 739

703 462 366 300 224 169 137 115 98 86 27.4 32.6 40.2 709

747 423 367 312 234 178 142 116 99 89 27.8 36.5 38.6 722

800 534 431 350 256 192 153 126 105 91 27.5 33.1 40.2 690

848 433 356 307 224 170 134 110 93 82 27.5 35.2 38.6 707

901 550 411 306 189 129 101 85 74 65 27.5 33.2 40.2 714

950 637 482 372 250 180 139 112 93 80 27.4 34.5 38.6 747

1003 500 417 340 238 167 122 96 81 72 27.9 33.7 40.2 717

1049 Rutting 327 266 230 177 138 113 94 81 72 27.3 34.1 38.6 741

1103 400 332 283 205 144 107 83 68 58 28.2 34.4 40.2 690

1150 1012 750 547 338 228 176 149 132 118 27.4 34 38.6 717

1202 415 338 271 187 129 101 84 72 63 27.8 34.6 40.2 687

1243

After

Bumps,

Rutting 581 427 331 222 155 116 90 74 63 27.7 35.1 38.6 749

1302 564 430 332 220 155 118 95 78 69 27.8 34.8 40.2 709

1348 612 451 336 219 161 131 109 94 82 27.6 35.8 38.6 717

1402

After

Bump 652 470 339 212 152 124 106 93 83 27.6 35.1 40.2 678

1450 599 486 396 277 202 160 129 110 94 27.3 35.9 38.6 726

66

1501 546 416 336 229 162 125 102 88 79 27.6 35 40.2 699

1550 595 480 374 247 172 135 112 96 84 27.5 36 38.6 730

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

1605 587 448 353 236 171 133 110 95 84 27.4 34.9 40.2 721

1637

After

Culvert 1024 771 582 385 282 228 193 168 150 27.1 35.8 38.6 717

1700 413 330 258 185 137 108 89 75 66 27 34.9 40.2 718

1750 428 337 266 185 132 104 84 71 62 26.9 35.9 38.6 743

1808 456 345 260 163 111 87 74 65 60 27.1 35 40.2 718

1849 487 366 290 194 134 103 85 74 65 27.3 35.6 38.6 729

1901 578 478 386 270 190 140 111 92 78 27.4 35.3 40.2 687

1950 531 417 322 219 158 128 106 90 78 27.5 35.4 38.6 750

2003 794 609 463 294 195 140 110 91 78 27.3 35.4 40.2 713

2050 326 276 234 178 142 115 93 78 66 27.7 34.7 38.6 720

2104

Kambi

GabraJn 523 451 377 282 209 162 124 98 77 26.9 35.1 40.2 711

2150 500 438 384 304 237 191 160 133 109 28.1 34.9 38.6 721

2202 245 223 200 165 138 116 94 76 61 27 34.8 40.2 704

2248 342 266 216 158 115 89 69 54 44 27.8 34.8 38.6 724

2300 706 608 533 429 341 273 205 160 128 26.7 34.5 40.2 671

2349 472 399 337 261 202 160 126 100 80 27.3 34 38.6 742

2399 672 578 509 398 311 242 192 151 121 26.8 34.3 40.2 667

2449 402 337 291 223 171 136 108 86 70 27.1 34.2 38.6 727

2501 641 553 464 339 247 188 141 104 79 26.9 34.2 40.2 683

2550

Deformatio

n 1011 847 694 479 327 232 170 129 100 27.2 33.9 38.6 695

2602 715 583 460 320 232 175 136 107 85 27 34.8 40.2 703

2648 Rutting 656 515 408 284 193 144 110 88 72 27 32.9 38.6 740

2711 912 722 563 394 277 209 162 133 113 27.3 35 40.2 678

2746

Longitudina

l Crack 1467 618 506 358 259 191 142 108 90 27.3 33.7 38.6 714

2802 675 538 437 299 208 147 110 86 71 27.7 34.6 40.2 699

2850 921 750 627 469 349 264 205 160 131 27.3 33.4 38.6 717

2902 669 537 437 312 227 175 140 120 104 27.7 34.5 40.2 683

2949 788 620 480 324 224 167 133 110 93 27.7 33.9 38.6 701

3001 604 527 452 342 256 199 156 122 100 27.7 34.8 40.2 672

3049

Before

New Life

Home

Gate,L 693 566 467 343 258 202 161 132 112 27.9 33.5 38.6 718

3106 1113 914 754 530 372 274 204 164 140 27.8 34.9 40.2 670

67

3150 716 611 498 353 258 201 159 132 114 27.4 33.1 38.6 716

3203 610 520 437 337 262 207 164 131 108 27.9 34.9 40.2 702

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

3250

After Camp

Garba

Catholic

Mission,

Gate,Lhs 896 713 541 352 237 166 124 98 82 28.1 33.3 38.6 734

3300 513 434 364 268 197 148 114 94 80 27.7 34.9 40.2 703

3350 598 473 361 226 150 109 85 72 61 26.9 33.5 29.9 735

3401 552 446 355 245 166 122 94 76 64 27.5 34.7 40.2 719

3450 782 617 476 302 198 145 113 93 80 27.1 34.7 29.9 731

3504 542 406 297 184 127 100 84 72 63 27.5 34.5 40.2 728

3550 590 465 367 247 172 127 100 83 71 27.2 34.7 29.9 733

3603 449 351 281 198 141 108 88 72 62 27.6 34.8 40.2 704

3647 615 508 422 305 218 163 125 99 82 27.4 34.9 29.9 723

3701 611 503 404 282 197 142 108 87 73 27.8 34.8 40.2 688

3750

Longitudina

l Crack 778 611 490 329 217 158 125 105 90 27.7 34.9 29.9 715

3805 777 633 501 347 253 192 148 116 92 27.9 35.3 40.2 707

3850 523 434 363 273 206 163 131 108 90 27.6 34.8 29.9 713

3901 475 364 293 211 154 121 97 78 64 27.9 35.2 40.2 690

3945 420 368 332 270 220 180 147 120 99 27.6 35.3 29.9 715

4001 452 384 332 255 189 142 105 81 66 27.8 35.2 40.2 707

4050 420 364 322 256 202 163 134 111 94 27 36 29.9 731

4105 802 663 542 383 267 198 148 118 99 27.9 35.5 40.2 682

4149 657 539 435 310 226 178 147 124 107 26.7 35.5 29.9 737

4200 485 393 318 222 161 124 100 84 74 28 35.4 40.2 723

4249 650 532 430 309 228 175 139 112 94 26.7 35.1 29.9 723

4302 500 408 329 230 164 125 100 84 72 27.7 35.5 40.2 693

4350 567 486 405 300 222 171 133 108 91 26.7 34.9 29.9 730

4404 708 595 502 378 284 219 172 138 114 27.6 35.6 40.2 689

4445 706 608 520 396 302 237 187 154 129 26.6 34.8 29.9 686

4509

Cracks At

Edge 1981 795 658 473 346 268 209 169 139 27.5 35.6 40.2 653

4550 106 870 724 512 361 266 203 161 134 26.8 34.2 29.9 703

4601 790 640 535 391 287 217 171 141 121 27.5 35.4 40.2 661

4650 633 516 422 296 216 166 131 108 90 26.8 34 29.9 714

4701 1209 978 792 550 377 270 203 161 130 27.2 35.5 40.2 653

4747 916 729 569 376 255 181 135 111 94 27 34.1 29.9 738

4803 748 623 516 381 284 220 173 140 118 27.2 35.9 40.2 694

68

4850

After Home

Of

Gunners,Rh

s 722 591 493 362 270 209 168 137 114 27 34.1 29.9 724

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

4901

School Of

Artillery

RHS 835 706 588 425 306 226 174 140 116 27.2 35.9 40.2 695

4947 822 702 620 500 397 315 247 197 160 27.5 33.8 29.9 704

5050 964 792 659 479 352 263 202 162 134 27.7 34.2 29.9 699

5103 815 677 556 392 278 204 155 128 110 27 35.9 40.2 693

5150 643 568 483 365 274 209 163 132 111 28.4 34.4 29.9 702

5201 582 473 387 281 201 153 122 102 88 27 35.8 40.2 713

5248 698 570 471 330 232 176 140 116 99 28 35.3 29.9 704

5301 732 590 479 329 222 155 112 87 73 27.1 35.3 40.2 682

5348 537 447 374 275 205 152 120 99 86 27.6 34.7 29.9 708

5402 552 470 404 314 235 186 143 114 94 27 35.5 40.2 697

5449 578 481 386 274 198 149 117 96 83 27.3 34.8 29.9 706

5501 599 493 406 295 214 160 124 100 83 27 35.7 40.2 706

5549 658 553 447 316 228 176 137 110 90 27.2 34.5 29.9 716

5606 476 400 330 237 171 132 104 85 73 27 35.7 40.2 695

5649 rutting 1047 861 674 443 300 218 170 138 116 27.1 33.7 29.9 704

5704 426 353 297 219 159 121 94 74 61 27.1 35.7 40.2 692

5750 662 550 455 333 242 181 137 106 84 27.3 34.7 29.9 708

5800 442 368 311 232 172 132 103 82 68 27.2 35.7 40.2 696

5848 576 486 393 278 196 142 108 86 73 27.8 35.1 29.9 708

5903 252 217 194 155 122 100 83 68 57 27.1 36 40.2 701

5950 Transverse

Cracks 430 389 334 243 169 124 100 83 71 28.3 34.8 29.9 726

6002 374 305 256 193 145 114 91 74 61 27 35.9 40.2 686

6049 602 482 385 261 175 127 96 77 66 28.2 34.8 29.9 715

6103 333 268 226 168 126 101 82 67 56 26.9 35.8 40.2 696

6150 466 395 329 245 186 147 120 99 86 27.7 34 29.9 744

6202 394 329 288 228 176 138 108 86 70 26.9 35.9 40.2 692

6250 318 266 237 188 148 121 101 85 73 27.3 33.9 29.9 739

6307 496 425 357 265 200 156 123 98 82 27 35.9 40.2 676

6349 291 249 215 167 129 106 87 73 63 26.9 34.4 29.9 731

6400 434 369 314 238 179 141 112 90 73 27.1 36 40.2 706

6449

Longitudinal

Cracks At

The Edge Of

The Carriage 558 461 375 277 209 160 130 110 96 26.8 34.2 29.9 719

69

Way

6502 307 277 254 209 167 136 112 90 75 27.3 35.6 36 693

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

6550 255 225 203 165 130 106 88 74 62 26.7 34.1 29.9 711

6601 292 259 238 197 160 133 112 92 78 27 35.8 36 706

6647 265 222 197 157 122 100 82 71 61 26.7 34.4 29.9 730

6710 424 376 324 248 186 146 115 93 76 26.8 36.1 36 714

6750 398 338 296 228 173 137 109 88 74 27.4 34 29.9 729

6801 308 292 268 211 162 130 104 86 72 26.9 36.3 36 688

6846 361 310 272 214 165 134 107 87 72 27.4 34.4 29.9 735

6903 315 272 239 190 148 120 96 78 65 26.7 36 36 693

6950 474 408 354 276 214 167 133 107 87 27.3 34.3 29.9 741

7001 601 476 394 278 188 135 104 84 73 26.6 35.7 36 693

7050 345 274 232 175 132 105 85 70 58 27.5 33.9 29.9 746

7101 318 276 246 198 157 129 106 90 77 26.3 36.1 36 682

7150 481 406 349 274 218 177 146 122 102 27 33.8 29.9 730

7201 235 210 194 164 137 120 106 92 83 26.5 36.2 36 691

7248 461 351 285 206 152 121 99 84 75 27.1 33.1 29.9 747

7304 386 324 266 191 141 114 95 80 69 26.8 36.4 36 709

7347 221 182 160 126 99 83 70 60 52 27.1 32.4 29.9 726

7402 578 486 422 306 225 178 135 102 84 26.8 36.3 36 691

7443 400 322 278 211 154 120 98 81 68 26.9 32.7 29.9 740

7504 547 456 394 296 223 171 134 106 85 26.8 36.5 36 696

7550 285 255 227 173 132 106 86 73 63 26.9 32.7 29.9 739

7608 344 288 230 159 116 92 75 62 54 27 36.6 36 697

7646 451 352 263 174 125 102 85 73 64 26.8 32.1 29.9 744

7714 448 380 326 242 175 139 110 90 76 26.9 36.8 36 703

7749 796 677 569 436 331 248 184 141 111 26.8 31.9 29.9 710

7808 708 586 482 340 251 192 150 118 96 26.9 36.7 36 683

7850 404 355 320 259 202 161 128 104 86 26.6 30.8 29.9 742

7901 756 627 530 382 267 192 138 107 89 26.9 36.5 36 669

7950 1365

109

1 863 557 353 244 183 148 126 26.7 30.3 29.9 702

8001 862 674 532 359 249 181 140 114 98 26.8 35.7 36 668

8050

Longitudina

l Cracks At

The Edge

Of The

Carriage 604 505 416 314 239 182 138 109 90 26.5 30.5 29.9 720

8108 1037 837 684 482 326 219 158 127 108 26.5 34.1 36 664

8151 854 730 588 390 289 220 167 123 99 26.7 31.5 29.9 713

70

8202 670 557 469 350 264 205 165 137 117 26.2 33.7 36 676

8248 Longitudina 443 368 321 255 203 166 136 112 94 26.8 31.8 29.9 715

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

8303 798 656 537 390 286 222 180 151 130 26.1 33.5 36 688

8345

Longitudina

l Crack At

The Edge

Of Carriage

Way 1167 958 785 559 396 290 225 185 155 26.9 31.3 29.9 697

8405 703 569 476 346 254 198 161 136 119 26 33.3 36 691

8449

Longitudina

l Rack At

Owp 818 659 541 382 271 199 153 126 108 26.7 31.1 29.9 721

8502 728 608 513 376 272 200 159 129 109 26 32.6 36 668

8550 868 682 539 362 246 180 143 120 105 27.1 31 29.9 723

8605 W 1091 864 698 481 333 248 193 157 133 25.9 32.3 36 678

8649

Sealed

Longitudina

l Cracks At

The Owp 978 790 633 438 310 234 186 155 132 27 30.8 29.9 714

8702

Rutting At

Owp 1545

124

2 ### 669 436 293 213 168 142 25.9 32.1 36 631

8744

Sealed

Longitudina

l Cracks At

The Edge 1408

115

6 960 682 479 333 232 183 155 26.8 30.7 29.9 675

8806

Rutting At

Owp 810 667 567 422 302 220 164 130 107 25.9 31.8 36 694

8837 Rutting 1695

138

3 ### 707 443 298 226 181 155 26.7 30.6 29.9 661

8910 881 706 568 393 278 207 160 132 114 25.9 31.6 36 656

8950

Longitudina

l Crack At

Owp 900 722 576 392 269 200 159 133 115 26.2 30.8 29.9 727

9005 714 601 507 380 286 222 175 142 118 25.9 31.7 36 687

9049 655 524 426 296 207 150 117 96 84 26.1 31.9 29.9 717

9107 468 388 321 234 174 137 111 92 80 25.9 31.8 36 682

9150 885 727 590 416 290 208 163 136 116 26 31.6 39.4 713

9201

Rutting At

Owp 496 418 355 268 204 160 128 104 85 25.9 31.9 36 681

9249

Sealed

Longitudina

l Cracks At

Owp 803 651 534 376 267 196 154 126 108 26.2 31.1 39.4 716

9305 795 671 559 400 284 210 160 127 104 25.9 31.4 36 672

71

9347 734 597 486 349 248 184 144 116 100 26.3 30.9 39.4 723

9402 944 770 633 448 309 221 165 133 112 25.8 31.3 36 670

9444 Rutting 876 704 588 422 298 216 166 134 113 26 30.2 39.4 722

9501 560 478 421 328 246 191 150 120 100 25.8 31.2 36 673

9547 817 673 566 416 308 230 180 146 123 25.9 29.9 39.4 726

9602

Sealed

Cracks At

Owp 956 758 621 430 301 220 170 141 121 25.7 30.5 36 660

9650

Sealed

Longitudina

l Cracks At

Owp 782 659 573 447 343 264 200 155 122 25.7 29.7 39.4 733

9701 697 589 498 374 275 208 157 124 102 25.6 29.3 36 672

9748 883 733 623 464 345 258 201 163 135 25.5 30.1 39.4 706

9810 805 655 536 378 277 208 161 127 106 25.5 28.6 36 677

9848 648 543 461 355 275 212 164 132 106 25.3 29.8 39.4 726

9908 766 616 494 344 243 178 136 108 90 25.4 28 36 682

9949

Deformatio

n 1115 905 741 508 349 249 187 149 124 25 29.7 39.4 713

10006 516 400 314 223 159 123 99 84 72 25.3 28.8 36 683

10050 1008 832 681 484 349 258 193 152 125 25 29.4 39.4 716

10102 653 541 452 329 234 172 131 103 85 25.2 28.4 36 657

10151 550 482 423 328 251 195 150 120 97 25 29.6 39.4 729

10209 792 665 559 416 309 238 189 155 131 25.1 28.2 36 654

10249 748 624 538 415 319 249 194 154 125 25.2 29.6 39.4 724

10302 464 415 362 284 221 180 148 121 102 25 28.3 36 661

10347 697 592 504 387 304 241 195 160 135 25.1 29.5 39.4 720

10406 379 305 277 229 187 156 130 108 93 24.9 28.2 36 692

10449

Longitudina

l Crack At

Owp 916 757 634 469 351 275 226 188 160 25.4 29.9 39.4 678

10504 307 265 232 181 142 118 99 84 74 24.8 28.1 36 698

10549 750 628 524 386 287 220 173 139 116 25.5 30.5 39.4 711

10603 314 258 222 172 134 112 95 81 71 24.8 28.6 36 696

10643 508 448 398 333 279 237 197 164 136 25.5 30.6 39.4 718

10745 232 189 167 130 102 85 72 63 56 25.2 30.9 39.4 724

10748 221 174 147 113 88 76 66 57 51 24.6 28.8 36 684

10801 446 358 299 225 173 140 116 97 83 24.5 28.2 36 683

10851 500 414 352 271 211 170 136 109 91 25.2 31 39.4 715

10901 452 224 183 132 96 79 67 57 51 24.5 28.2 36 703

10947 451 388 338 262 205 164 134 112 97 25.4 31.2 39.4 725

11000 414 324 262 180 127 98 80 67 59 24.5 28.6 36 680

11047 600 502 415 315 243 192 156 129 108 25.9 31.1 39.4 734

72

11102 422 318 259 184 132 102 83 70 62 24.5 28.1 36 716

11143 606 559 509 430 364 308 262 224 187 26 31 39.4 714

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

11200 366 320 280 221 176 144 118 100 86 24.5 27.8 36 692

11247 320 260 225 178 141 117 98 83 74 25.7 30.8 39.4 728

11307 333 314 291 234 187 155 128 108 92 24.4 28.1 36 708

11349 318 290 268 226 186 154 127 104 85 25.4 30.7 39.4 732

11401

Sealed

Cracks 226 199 183 153 125 107 92 79 69 24.4 27.7 36 678

11450 253 232 218 189 161 142 123 107 93 25 30.7 39.4 717

11505 288 257 238 198 160 138 118 102 88 24.4 27.3 36 673

11549 443 409 356 296 249 211 175 146 123 24.9 31.1 39.4 718

11606 157 139 128 104 82 70 61 53 47 24.4 27.1 36 669

11648 461 355 276 184 122 86 65 52 44 24.8 31.2 39.4 745

11700 180 153 139 112 88 71 59 50 43 24.4 26.9 36 710

11750 192 156 125 86 61 49 42 36 32 24.8 31.1 39.4 746

11802 333 291 249 192 147 120 99 81 70 24.4 26.5 36 696

11850 256 210 174 122 86 64 49 39 34 24.8 31 39.4 751

11906 244 202 171 128 94 72 57 46 39 24.3 26.3 36 714

11950 283 228 187 125 83 61 47 39 34 24.8 31.2 39.4 752

12009 162 135 114 84 62 50 42 37 33 24.2 25.6 36 688

12050 293 247 202 142 99 76 59 46 37 24.7 30.8 39.4 726

12110 168 140 122 94 69 55 46 39 34 23.2 24.8 36 707

12148 148 117 103 80 61 51 44 37 34 24.9 30.6 39.4 729

12202 224 185 161 125 90 70 55 43 35 22.9 24.8 36 705

12237 194 160 140 110 84 68 55 45 39 25 30.9 39.4 718

12312 218 165 134 93 64 50 41 35 31 22.8 24.6 30.9 706

12348 866 154 124 83 56 42 35 30 27 25.3 31.6 39.4 735

12403 169 135 109 77 55 45 37 33 29 22.7 24.3 30.9 699

12444 221 175 140 100 70 53 42 35 30 25.4 32.4 39.4 730

12500 211 168 136 92 64 50 42 35 31 22.7 23.9 30.9 714

12550 203 152 121 82 56 43 34 28 25 25.5 32 39.4 731

12600 312 264 217 156 114 90 75 64 55 22.7 24.2 30.9 679

12650 251 211 186 149 119 100 84 72 63 25.5 32.6 39.4 714

12705 384 317 262 190 138 104 81 65 54 22.8 25 30.9 672

12749 261 211 177 134 104 86 72 60 52 25.6 32.8 39.4 729

12804 455 380 317 235 174 137 111 91 77 22.8 24.9 30.9 700

12849 296 233 186 130 94 77 66 58 52 25.8 32.2 39.4 683

12911 344 267 217 157 116 93 79 67 59 22.8 25.1 30.9 703

12950 367 286 231 166 123 99 82 69 60 25.8 32 39.4 726

73

13002 308 256 213 157 119 95 77 65 56 22.8 25.4 30.9 671

13050 418 330 268 191 141 112 91 77 66 25.8 32 39.4 729

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

13101 288 247 215 172 138 116 98 82 70 22.7 26 30.9 663

13150 266 226 193 151 120 99 84 72 62 25.8 32.4 39.4 713

13202 180 150 134 105 80 67 56 48 41 22.8 26.3 30.9 684

13247 198 178 146 111 71 39 34 32 30 25.7 32.2 39.4 721

13301 152 127 114 90 69 58 50 43 37 22.8 26.3 30.9 668

13350 182 168 162 147 130 118 96 62 51 25.6 31.6 39.4 732

13401 233 186 164 131 105 90 78 67 58 22.8 26.2 30.9 679

13448 153 143 135 112 92 78 67 57 49 25.8 31.2 39.4 732

13500 168 153 146 126 107 96 86 76 67 22.8 25.5 30.9 676

13542

Sealed

Cracks At

Owp 413 362 325 265 210 167 132 105 85 26 31.6 39.4 705

13603 256 240 228 199 168 142 118 98 81 22.9 25.1 30.9 686

13650 364 311 274 213 166 134 107 87 74 26.1 32 39.4 736

13702 336 284 245 195 153 126 104 85 70 22.9 25 30.9 666

13747 300 265 243 207 172 146 122 102 87 26.1 32.8 39.4 736

13805 242 207 180 140 108 90 75 63 54 22.8 25.6 30.9 668

13850 241 214 194 159 128 101 78 66 57 26.1 33.1 39.4 724

13903 380 320 270 198 146 115 92 75 64 22.9 26.2 30.9 676

13948 356 285 235 172 128 100 81 68 58 26 33.1 39.4 726

14010 254 220 194 151 116 94 78 64 55 22.9 26.7 30.9 687

14048 326 274 233 175 132 104 83 68 58 26 32.5 39.4 727

14107 239 217 192 157 128 108 92 77 65 23 26.9 30.9 670

14146

Sealed

Cracks At

Owp 324 273 235 186 148 123 103 87 74 26 32.4 39.4 717

14204

Sealed

Cracks At

Owp 380 336 289 228 178 143 115 90 72 23 27 30.9 681

14250 555 450 372 273 199 152 118 95 77 26.2 32.6 39.4 742

14303 246 197 166 130 102 82 67 56 48 23.1 27 30.9 692

14350

Sealed

Cracks At

Owp 354 290 234 156 110 86 69 56 48 26.2 33.1 39.4 729

14409

Sealed

Cracks At

Owp 667 558 467 332 211 158 128 107 91 23.1 26.8 30.9 671

14447 513 451 366 246 172 134 108 90 76 26.3 33.3 39.4 729

14502 253 217 193 155 122 100 82 67 56 23.1 26.7 30.9 671

74

14548 693 568 456 309 215 162 132 112 94 26.4 33.2 39.4 720

14606 273 240 220 182 146 121 99 80 66 23.1 26.8 30.9 693

Chaina

ge (m) Remarks d1 d2 d3 d4 d5 d6 d7 d8 d9

Air

Tem

p.

Surfac

e

Temp

Pavemen

t Temp

Test

Press

ure

KPa

14646

Sealed

Cracks At

Owp 739 607 498 338 231 166 125 101 87 26.5 33.5 39.4 734

14701 328 287 256 208 169 140 117 97 80 23.1 26.9 30.9 682

14750 337 299 271 228 184 148 120 96 79 26.5 33.6 39.4 722

14801 280 237 210 164 128 102 83 67 57 23.1 26.9 30.9 670

14842 225 211 200 174 154 130 111 94 79 26.3 33.6 39.4 718

14900 403 347 300 235 183 149 122 102 85 23.1 27.2 30.9 694

14950 185 160 134 102 77 63 52 44 38 26.1 32.9 39.4 725

15000

End Of

Lhs,15Km 304 287 270 238 196 161 128 99 76 23.1 27.7 30.9 670

15000

Start Of Rhs

Section,Km

15+000 327 276 250 207 166 134 106 82 63 26.5 33 39.4 738

75

APPENDIX C

C.PAVEMENT ROUGHNESS DATA

76

Table 13.Measured roughness.

SectionID SubDistance TotalDistance IRI NAASRA Speed Event

1 0.1 0.1 17.8 470 26.3

1 0.2 0.2 3.1 81 52.1

1 0.3 0.3 2.5 64 51.6

1 0.4 0.4 3.2 84 53.2

1 0.5 0.5 2.4 61 54.3

1 0.6 0.6 2 51 54.4

1 0.7 0.7 2.2 58 54.2

1 0.8 0.8 1.7 44 52.7

1 0.9 0.9 2.2 56 52.1

1 1 1 1.8 47 51.4

1 1.1 1.1 2.6 68 49.1

1 1.2 1.2 14 369 23.1 bump

1 1.3 1.3 11.3 297 28.3

1 1.4 1.4 16.8 444 30.1 bump

1 1.5 1.5 5.2 137 51.1

1 1.6 1.6 2.6 67 55.7

1 1.7 1.7 2.6 67 53.5

1 1.8 1.8 2.1 54 54.4

1 1.9 1.9 2.4 62 55.5

1 2 2 2.2 57 55.4

1 2.101 2.101 3.2 84 53.7

1 2.201 2.201 3.7 97 52.8

1 2.301 2.301 3.7 96 52.9

1 2.401 2.401 2.9 76 53.3

1 2.501 2.501 4.9 129 48.6 bump

1 2.601 2.601 15.7 414 40.6

1 2.701 2.701 3.3 85 56.1

1 2.801 2.801 3.1 82 56.2

1 2.901 2.901 3.8 98 55

1 3.001 3.001 3.1 81 53.1

1 3.101 3.101 3.9 102 54.3

1 3.201 3.201 5.8 152 45.4 bump

77

1 3.301 3.301 6 157 46.2 bump

1 3.401 3.401 26.2 692 43.1 bump

1 3.501 3.501 16.6 440 37.6

1 3.601 3.601 3.7 98 54.9

1 3.701 3.701 2.7 69 55.6

1 3.801 3.801 2.5 65 56.2

1 3.901 3.901 2.9 75 55

SectionID SubDistance TotalDistance IRI NAASRA Speed Event

1 4.001 4.001 2.6 67 55.6

1 4.101 4.101 2.5 66 54.1

1 4.201 4.201 2.8 73 52.8

1 4.301 4.301 2.6 68 53.3

1 4.401 4.401 3.8 98 54.4

1 4.501 4.501 2.6 66 55

1 4.601 4.601 2.8 74 54.5

1 4.701 4.701 2.4 61 54.4

1 4.801 4.801 2.6 69 55.6

1 4.901 4.901 2.4 63 55.6

1 5.001 5.001 3.7 97 55

1 5.101 5.101 2.3 60 55

1 5.201 5.201 2.9 77 54.9

1 5.301 5.301 2.6 66 54.2

1 5.401 5.401 3 79 54.4

1 5.501 5.501 3.1 80 56.2

1 5.601 5.601 3.5 92 57.8

1 5.701 5.701 2.5 65 57.9

1 5.801 5.801 2.1 54 55.9

1 5.901 5.901 2.3 60 56.4

1 6.001 6.001 3.1 81 56.1

1 6.102 6.102 2 53 56.5

1 6.202 6.202 2.6 68 56.2

1 6.302 6.302 2.2 57 53.7

1 6.402 6.402 2.2 56 52.2

1 6.502 6.502 2.1 55 49.9

1 6.602 6.602 2.5 65 54.3

1 6.702 6.702 2.2 58 56

1 6.802 6.802 2.5 64 56.3

1 6.902 6.902 2 53 56.2

1 7.002 7.002 1.8 46 58

1 7.102 7.102 2.1 56 56.4

1 7.202 7.202 1.7 45 56.1

78

1 7.302 7.302 1.9 50 55.6

1 7.402 7.402 1.6 42 52.6

1 7.502 7.502 2 51 54.1

1 7.602 7.602 2 51 55

1 7.702 7.702 2.3 59 56.5

1 7.802 7.802 2.4 62 55.1

1 7.902 7.902 2.4 61 56.2

SectionID SubDistance TotalDistance IRI NAASRA Speed Event

1 8.002 8.002 2.4 62 56.6

1 8.102 8.102 2 52 56.3

1 8.202 8.202 2.4 63 53.9

1 8.302 8.302 2.3 59 53.7

1 8.402 8.402 2.1 54 56

1 8.502 8.502 2.6 68 58.4

1 8.602 8.602 2.2 56 56.2

1 8.702 8.702 2.9 75 56.5

1 8.802 8.802 2.5 66 55.8

1 8.902 8.902 2.7 71 54.2

1 9.002 9.002 2.9 75 55.6

1 9.102 9.102 2.1 55 55

1 9.202 9.202 2 51 55.9

1 9.302 9.302 1.9 50 56.9

1 9.402 9.402 2.6 69 56.9

1 9.502 9.502 3 79 55.7

1 9.602 9.602 3.2 85 53.5

1 9.702 9.702 2 51 52.7

1 9.802 9.802 2.6 69 52.1

1 9.902 9.902 4.2 109 51.2

1 10.002 10.002 3 79 51.2

1 10.103 10.103 3.3 87 54.8

1 10.203 10.203 2.4 63 56.4

1 10.303 10.303 2.3 60 57.4

1 10.403 10.403 1.9 48 56.8

1 10.503 10.503 2.5 65 56.7

1 10.603 10.603 2.6 67 56.5

1 10.703 10.703 1.7 43 55.6

1 10.803 10.803 1.9 50 54.5

1 10.903 10.903 1.9 50 54.7

1 11.003 11.003 2 52 55.3

1 11.103 11.103 2.1 55 55.4

79

1 11.203 11.203 2.4 62 54.9

1 11.303 11.303 2.4 63 56.1

1 11.403 11.403 3.4 89 56

1 11.503 11.503 2.7 71 55.1

1 11.603 11.603 2.4 62 55.3

1 11.703 11.703 1.9 49 55.8

1 11.803 11.803 1.8 47 55.8

1 11.903 11.903 1.9 50 55.3

SectionID SubDistance TotalDistance IRI NAASRA Speed Event

1 12.003 12.003 2.1 53 54.5

1 12.103 12.103 2 51 55.1

1 12.203 12.203 2.1 53 56.5

1 12.303 12.303 1.6 42 56.3

1 12.403 12.403 2 51 55.6

1 12.503 12.503 1.9 48 56.3

1 12.603 12.603 2 53 54.3

1 12.703 12.703 2.4 63 53.8

1 12.803 12.803 2.4 62 53.2

1 12.903 12.903 3.3 86 49.7 bump

1 13.003 13.003 21.8 576 21.8 bump

1 13.103 13.103 21.6 572 27.4 bump

1 13.203 13.203 19.5 515 20.9

1 13.303 13.303 5.9 155 49.2

1 13.403 13.403 2.9 76 60.5

1 13.503 13.503 3 78 58.1

1 13.603 13.603 2.1 55 53.8

1 13.703 13.703 2.3 60 54.5

1 13.803 13.803 1.9 49 54.1

1 13.903 13.903 2.4 61 52.6

1 14.003 14.003 2.2 57 53.7

1 14.104 14.104 2.1 54 54

1 14.204 14.204 2.1 55 54.2

1 14.304 14.304 3 77 54.4

1 14.404 14.404 2.5 64 53.4

1 14.504 14.504 2.2 57 51.9

1 14.604 14.604 2.7 70 51.4

1 14.704 14.704 2.5 65 52.9

1 14.804 14.804 10.9 287 45

80

1 14.904 14.904 25.3 668 33

1 15.022 15.022 11.4 302 13.8 Bump

81

APPENDIX D

D.PAVEMENT THICKNESS

82

Pavement thickness at different sections

Figure 13.Pavement thickness at different sections.

83

APPENDIX E

E.ANALYSED ROUGHNESS DATA

84

Table 14.Showing calculated PSI and IRI

Chainage

IRI PSI Condition Chainage IRI PSI Condition

0.1 17.8 0.203 Very Bad 4.101 2.9 2.97 Fair

0.2 3.1 2.86 Fair 4.201 2.6 3.13 Good

0.3 2.5 3.19 Good 4.301 2.5 3.19 Good

0.4 3.2 2.81 Fair 4.401 2.8 3.02 Good

0.5 2.4 3.25 Good 4.501 2.6 3.13 Good

0.6 2 3.49 Good 4.601 3.8 2.52 Fair

0.7 2.2 3.37 Good 4.701 2.6 3.13 Good

0.8 1.7 3.68 Good 4.801 2.8 3.02 Good

0.9 2.2 3.37 Good 4.901 2.4 3.25 Good

1 1.8 3.62 Good 5.001 2.6 3.13 Good

1.1 2.6 3.13 Good 5.101 2.4 3.25 Good

1.2 14 0.4 Very Bad 5.201 3.7 2.57 Fair

1.3 11.3 0.65 Very Bad 5.301 2.3 3.31 Good

1.4 16.8 0.24 Very Bad 5.401 2.9 2.97 Fair

1.5 5.2 1.96 Bad 5.501 2.6 3.13 Good

1.6 2.6 3.13 Good 5.601 3 2.91 Fair

1.7 2.6 3.13 Good 5.701 3.1 2.86 Fair

1.8 2.1 3.43 Good 5.801 3.5 2.66 Fair

1.9 2.4 3.25 Good 5.901 2.5 3.19 Good

2 2.2 3.37 Good 6.001 2.1 3.43 Good

2.101 3.2 2.81 Fair 6.102 2.3 3.31 Good

2.201 3.7 2.57 Fair 6.202 3.1 2.86 Fair

2.301 3.7 2.57 Fair 6.302 2 3.49 Good

2.401 2.9 2.97 Fair 6.402 2.6 3.13 Good

85

Chainage

IRI PSI Condition Chainage IRI PSI Condition

2.501 4.9 2.07 Fair 6.502 2.2 3.37 Good

2.601 15.7 0.29 Very Bad 6.602 2.2 3.37 Good

2.701 3.3 2.76 Fair 6.702 2.1 3.43 Good

2.801 3.1 2.86 Fair 6.802 2.5 3.19 Good

2.901 3.8 2.52 Fair 6.902 2.2 3.37 Good

3.001 3.1 2.86 Fair 7.002 2.5 3.19 Good

3.101 3.9 2.48 Fair 7.102 2 3.49 Good

3.201 5.8 1.76 Bad 7.202 1.8 3.61 Good

3.301 6 1.7 Bad 7.302 2.1 3.43 Good

3.401 26.2 0.04 Very Bad 7.402 1.7 3.68 Good

3.501 16.6 0.25 Very Bad 7.502 1.9 3.55 Good

3.601 3.7 2.57 Fair 7.602 1.6 3.75 Good

3.701 2.7 3.08 Good 7.702 2 3.49 Good

3.801 2.5 3.19 Good 7.802 2 3.49 Good

3.901 2.4 3.25 Good 7.902 2.3 3.31 Good

4.001 2.4 3.25 Good 8.002 1.9 3.55 Good

8.102 2.4 3.25 Good 12.103 1.6 3.75 Good

8.202 2 3.49 Good 12.203 2 3.49 Good

8.302 2.4 3.25 Good 12.303 1.9 3.55 Good

8.402 2.3 3.31 Good 12.403 2 3.49 Good

8.502 2.1 3.43 Good 12.503 2.4 3.25 Good

8.602 2.6 3.13 Good 12.603 2.4 3.25 Good

8.702 2.2 3.37 Good 12.703 3.3 2.76 Fair

8.802 2.9 2.97 Fair 12.803 21.8 0.1 Very Bad

8.902 2.5 3.19 Good 12.903 21.6 0.1 Very Bad

9.002 2.7 3.08 Good 13.003 19.5 0.15 Very Bad

9.102 2.9 2.97 Fair 13.103 5.9 1.73 Bad

9.202 2.1 3.43 Good 13.203 2.9 2.97 Fair

9.302 2 3.49 Good 13.303 3 2.91 Fair

9.402 1.9 3.55 Good 13.403 2.1 3.43 Good

9.502 2.6 3.13 Good 13.503 2.3 3.31 Good

9.602 3 2.91 Fair 13.603 1.9 3.55 Good

9.702 3.2 2.81 Fair 13.703 2.4 3.25 Good

9.802 2 3.49 Good 13.803 2.2 3.37 Good

9.902 2.6 3.13 Good 13.903 2.1 3.43 Good

10.002 4.2 2.35 Fair 14.003 2.1 3.43 Good

10.103 3 2.91 Fair 14.104 3 2.91 Fair

86

10.203 3.3 2.76 Fair 14.204 2.5 3.19 Good

Chainage

IRI PSI Condition Chainage IRI PSI Condition

10.303 2.4 3.25 Good 14.304 2.2 3.37 Good

10.403 2.3 3.31 Good 14.404 2.7 3.08 Good

10.503 1.9 3.55 Good 14.504 2.5 3.19 Good

10.603 2.5 3.19 Good 14.604 10.9 0.7 Very Bad

10.703 2.6 3.13 Good 14.704 25.3 0.05 Very Bad

10.803 1.7 3.68 Good 14.804 11.4 0.64 Very Bad

10.903 1.9 3.55 Good 14.904 2.1 3.43 Good

11.003 1.9 3.55 Good 15.015 2 3.49 Good

11.103 2 3.49 Good

11.203 2.1 3.43 Good

11.303 2.4 3.25 Good

11.403 2.4 3.25 Good

11.503 3.4 2.71 Fair

11.603 2.7 3.08 Good

11.703 2.4 3.25 Good

11.803 1.9 3.55 Good

11.903 1.8 3.61 Good

12.003 2.1 3.43 Good

87

APPENDIX F

F.TRAFFIC VOLUME COUNTS