Design of Flexible Pavement

CHAPTER 1
INTRODUCTION
1.1 GENERAL
A flexible pavement is a structure consisting of superimposed layers of processed materials

above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads
to the sub-grade. The pavement structure should be able to provide a surface of acceptable riding
quality, adequate skid resistance, and favorable light rejecting characteristics, and low noise
pollution. The ultimate aim is to ensure that the transmitted stresses due to wheel load are
sufficiently reduced so that will not exceed bearing capacity of the subgrade.
The surface of the roadways should be stable and non-yielding to allow the wheel loads of road
traffic to move with least possible rolling resistance. The surface should also be even along the
longitudinal profile to enable the fast vehicles to move safely and comfortably at the design
speed.
The earth road may not be able to fulfill any of the requirements especially during thevarying
conditions of traffic loads and the weather. At high moisture contents the soil becomes weaker
and soft and starts yielding under heavy wheel loads and thus increasing the tractive resistance.
The unevenness and undulation of the surface along the longitudinal profile of the vertical load
causes discomfort and fatigue to the passengers of the fast moving vehicles and cyclists, in order
to provide a stable and even surface for the traffic, the road is provided with a suitably designed
and constructed pavement structure.
The pavement carries the wheel loads and transfers the loads stresses through the wider area on
the soil subgrade below. Thus the stresses transferred to the subgrade soil through the pavement
layers are considerably lower than the contact pressure or compressive stresses under the wheel
load on the pavement surface.
A pavement layer is considered more effective or superior, if it is able to distribute the wheel
loadstress through a larger area per unit depth of the layer. However, there will be a small
CIVIL DEPARTMENT, GNITM 1

amount of temporary deformation ever on a good pavement surface when heavy wheel loads are
applied. One of the objectives of a well designed and constructed pavement is therefore to keep
this elastic deformation of the pavement within the permissible limits, so that the pavement can
sustain a large number of repeated load applications during the design life.
Based on the vertical alignment and the environmental conditions of the site, the pavement may
be constructed over an embankment, cut or almost at the ground level itself. It is always
desirable to construct the pavement well above the maximum level of the ground water to keep
the subgrade relatively dry even during monsoons.
1.2 OBJECTIVE
Better highway system provides varied benefits to the society. Improvements in highway results
in several benefits to the road users such as-
-The objective of laying pavement is to support the wheel loads and transfer the load stresses
through a wider area on soil sub grade, thus permitting the deformation within the elastic or
allowable range.
-Thus magnitude of stresses transferred to the sub grade soil through the pavement layers are
considerably lower than the contract pressure or compressive stresses directly under the wheel
load applied on the pavement surface.
-To reduce vehicle operational cost per unit length of road.
-To save travel time and resultant benefits in terms of time costs of vehicles and the passengers.
-To improve level of service and ease of driving.
-To increase comfort for passengers.
-To reduce the accident rates.
-To assess as to whether and to what extent the pavement fulfills the intended requirements so
that the maintenance and strengthening jobs could be planned in time.

Fig.1.1 View of flexible pavement

CHAPTER 2
2.1 LITERATURE REVIEW
A road is at through fare, route, or way on land between two places which typically has been
paved or otherwise improved to allow travel by some conveyance, including different class of
vehicles.
Roads consist of one, or sometimes two, roadways each with one or more lanes and also any
associated sidewalks and tree lawns. Roads that are available for use by the public may be
referred to as public roads or highways.
The roads connectivity is one of the key components for nation development, as it promotes
access to economic and social services, generating increased agricultural income and productive
employment. While building roads, the provisions based on the parameters that affect the
sustainability are to be made, but at minimum cost.
If the locally available materials, including marginal and industrial waste materials are utilized, it
Could be possible to reduce the cost of road constructions. Several types of new materials are
tried to establish the efficiency of new materials in road construction. However, the use of new
materials and technologies is not becoming popular owing to certain procedural constraints as
well as lack of awareness and therefore appropriate steps may have to be taken for popularizing
the new technologies for building better rural roads with less cost.
2.2 TYPES OF PAVEMENT SURFACE
Based on the structural behavior, pavements are generally classified into two categories:
1) Flexible pavements
2) Rigid pavements
2.2.1 FLEXIBLE PAVEMENTS

Flexible pavements are those which on the whole have low or negligible flexural strength and the
rather flexible in their structural action under the loads. The flexible pavement layers reflect the
deformation of the lower layers on-to the surface of the layer thus if the lower layer of the
pavement or soil sub grade is undulated a typical flexible pavements consists of four
components:
1) Soil sub grade

2) Sub base course
3) Base course
4) Surface course
The flexible pavement layers transmit the vertical or compressive stresses to the lower layers by
grain to grain transfer through the points of contact in the granular structure. A well compacted
granular structure consisting of strong graded aggregate can transfer the compressive stresses
through a wider area and thus forms a good flexible pavement layer. The load spreading ability
of this layer therefore depends on the type of the materials and the mix design factors.
Bituminous concrete is one of the most flexible pavement layer materials. Other materials which
fall under the group are all granular materials with or without bituminous binder, granular base
and sub-base course materials like the water bound macadam, crushed aggregate, gravel, soil-
aggregate mixes etc.
The vertical compressive stress is maximum on the pavement surface directly under the wheel
load and is equal to the contact pressure under the wheel. Due to the ability to distribute the
stresses to a larger area in the shape of a truncated cone, the stresses get decreased at the lower
layers. Therefore by taking full advantage of the stress distribution characteristics of the flexible
pavement may be constructed in a number of layer system concept was developed. According to
this, the flexible pavement may be constructed in a number of layer and the top layer has to be
the strongest as the highest compressive stresses are to be sustained by this layer, in addition to
the wear and tear due to the traffic. The lower layers have to take up only lesser magnitudes of
stresses and there is no direct wearing action due to traffic loads, therefore inferior materials with
lower cost can be used in the lower layers. The lowest layer is the prepared surface consisting of
the local soil itself, called the subgrade. Soil subgrade has the lowest stability among the four

typical flexible pavement components each of the flexible pavement layers above the subgrade,
viz. Sub-base, base course and surface course may consist of one or more number of layers of the
same or slightly different materials and specifications.
2.2.2 RIGID PAVEMENTS
Rigid pavements are those which possess noteworthy flexural strength or flexural rigidity. The
stresses are not transferred from grain to the lower layers as in case of flexible pavement layers.
The rigid pavements are made of Portland cement concrete-either plain, reinforced or pre-
stressed concrete the plain cement concrete slabs are expected to take up about 40 kg/cm2
flexural stress. The rigid pavement has the slab action and is capable of transmitting the wheel
load stresses through a wider area below.
The main of difference in the structural behavior of rigid pavement as compared to the flexible
pavement is that the critical condition of stress in the rigid pavement is the maximum flexural
stress occurring in the slab due to wheel load and the temperature changes where-as in the
flexible pavement it is the distribution of compressive stresses. As the rigid pavement slab has
tensile stresses are developed due to the bending of the slab under wheel load and temperature
variations. Thus the types of stresses developed and their distribution within the cement concrete
slab are quite different. The rigid pavement does not deformed to the shape of the lower surface
as it can bridge the minor variations of lower layer.
The cement concrete pavement slab can very well serve as well as an effective base course.
Therefore usually the rigid pavement structure consists of acement concrete slab, below which a
granular base or sub-base course may be provided. Though the cement concrete slab, below
which a granular base or sub-base course may be provided. The rigid pavements are usually
designed and the stresses are analyzedusing the elastic theory, assuming the pavement as an
elastic plate resting over an elastic or a viscous foundation.

2.3 TYPES OF ROADS AND THEIR CLASSIFICATION
2.3.1 BASED ON SEASONS OF THE YEAR
1) All-weather roads
All weather roads are those which are negotiate during all weather, except at major
rivers crossing where interruption to traffic is permissible up-to a certain extent.
2) Fair weather roads
Fair weatherroads are those on which traffic may be interrupted during monsoon
season where steam may across the road.
2.3.2 BASED ON TYPE OF CARRIG- WAY
1) Paved roads
Provided with hard pavement with at least having WBM layer.
2) Unpaved loads
Earth roads and gravel roads may be called unpaved roads
2.3.3 BASED ON TYPE OF PAVEMENT
1) Surface loads
Which are provided with a bituminous or cement concrete surfacing.
2) Un-surfaced roads
They are not provided with bituminous or cement concrete surfacing.
2.4 METHODS OF CLASSIFICATION OF ROAD
The roads are generally classified on the following basis:
a) Traffic volume
b) Load transported
2.4.1 TRAFFIC VOLUME:

The classification based on traffic volume has been arbitrarily fixed by different agencies and
there may not be a common agreement regarding the limits for each of classification group.
Based on traffic volume the roads are classified as:
1) Heavy traffic load

2) Medium traffic load
3) Light traffic load
2.4.2 LOAD TRANSPORTED:
The roads may be classified as class1, class2 etc. or class A, B etc. and the limits may be
expressed as tonnes per day.
2.4.3 LOCATION AND CLASSIFICATION:
The classification based on location and function should therefore be a more acceptable
classification as they may be defined clearly.
1) National Highway (NH):

They are the main highway running through the length and breadth in India, connecting
major ports foreign highways, capitals of large states and large industrial and tourist
centers including roads required for strategic movements for the defense of India.
2) State Highway (SH):

They are aerial roads of state, connecting up with the national highways of adjacent state,
district headquarters and important cities within the state and serving as the main arteries
for traffic to and from district roads.
3) Major District Roads (MDR):

They are important roads within a district serving areas of production and markets and
connecting those with each other or with the main highways of district. The MDR have
lower speed and geometric design specification than NH/SH.
4) Other District Roads (ODR):

They are serving rural areas of production and providing them with outlet to market
centers, tank headquarters, block development headquarters or other main roads. These
are of lower design specifications than MDR.
5) Village Roads (VR):

They are roads connecting villages or groups of villages with each other to the nearest
roads of highest category.

CHAPTER 3
METHODOLOGY
COMPLETE METHODOLOGY OF THE PROJECT WORK
3.1 DATA COLLECTION
For completion of project we will be collecting the following data-
1) Old traffic data

2) Data indicating the reason why strengthening of road is required as our project also
consists of maintenance of flexible pavements.
3) Direction for which the road is designed.
4) CBR value in present and CBR value in past.
5) Measurement of existing width.
3.2 DESIGN OF PAVEMENTS
Pavements design consists of two parts-
1) Mix design of the material to be used in each pavement component layer.

2) Thickness design of the pavement and the component layers.
The factors to be considered for the design of pavements-
1) Design wheel load

2) Subgrade soil
3) Climatic factors
4) Pavement component materials
5) Environmental factors
6) Special factors in the design of different types of pavements
3.2.1 DESIGN WHEEL LOAD

The thickness design of pavement primarily depends upon the design wheel load. Higher wheel
load need thicker pavement.
1) Maximum wheel load

2) Contact pressure
3) Dual or multiple wheel loads and equivalent single wheel load
4) Repetition of load
3.3 STANDARDS FOR FLEXIBLE PAVEMENT
1) The pavement should be designed for heavy volume of traffic of the order of 150 million
standard axles (msa).
2) The pavement designs should be for sub grade CBR values ranging from 2% to 10% and
design traffic ranging from 1 msa to 150 msa.
3) The recommended method considers traffic in terms of the cumulative number of
standard axles (8160kg) to be carried by the pavement during the design life.
4) The pavement for national highways and state highways should be designed for a life of
15 years.
5) Expresses and urban roads may be designed for a longer life of 20 years.
6) For other categories of roads, a design life of 10 to 15 years should be adopted.
7) For single-lane roads the design should be based on total number of commercial vehicles
in both directions.
8) For two-lane single carriageway roads the design should be based on 75% of the total
number of commercial vehicles in both directions.
9) For four- lane single carriageway roads the design should be based on 40% of the total
number of commercial vehicles in both directions.
10) For dual carriageway roads the design of dual two-lane carriageway roads should be
based on 75% of the number of commercial vehicles in each direction. For dual three-
lane carriageway and dual four-lane carriageway, the distribution factor will be 60% and
45% respectively.

11) For expressways, national highways and state highways, the material used for sub grade
construction should have the dry density of not less than 1.75 gm/cc.
12) The thickness of sub-base should not be less than 150 mm for design traffic less than 10
msa and 200 mm for design traffic of 10 msa and above.
13) The sub-grade soil should have a cbr of 2%.
14) The minimum thickness of granular base should be 225 mm for traffic up to 2 msa and
250 mm for traffic exceeding 2 msa.
3.4 STANDARDS FOR RIGID PAVEMENT
1) The basic design of the slab should be designed with a 98th percentile axle load.
2) The cement concrete pavements should be designed for life span of 30 years.
3) For two-lane two-way roads the 25% traffic of the total vehicles should be designed.
4) For four-lane and multi-lane divided highways 25% of the total traffic in the direction of
predominant traffic should be designed.
5) The limiting design deflection for cement pavements should be taken as 1.25 mm.
6) To permit warping at the joint, the maximum diameter of tie bars should be limited to 20
mm and to avoid concentration of tensile stresses they should not be spaced more than 75
mm apart.
3.5 COMPARISON OF STRUCTURAL DESIGN
The main difference in the structural behavior of rigid pavement as compared to the flexible
pavement is that the critical condition of stress in the rigid pavement is the maximum flexural
stress occurring in the slab due to wheel load and the temperature changes where-as in the
flexible pavement it is the distribution of the compressive stresses, as the rigid pavement slab has
tensile stresses are developed due to the bending of the slab under wheel load and temperature
variations thus the types stresses as the rigid pavement does not get deformed to the shape of the
lower surface as it can bridge the minor variations of the lower layer.

3.6 PAVEMENT EVALUATION
Pavement evaluation involves a thorough study of various factors such as subgrade support
pavement composition and its thickness, traffic and environmental conditions the primary
objective of pavement evaluation is to assess as to whether and to what extent the pavement
fulfill the intended requirements so that the maintenance and strengthening jobs could be planned
in time.
There are following two methods of pavement evaluations-
1) Structural evaluation of pavements

2) Evaluation of pavement surface condition
3.7 ESTIMATION AND COMPARISON OF COSTS
We are first estimate and then compare the total cost for both types of pavements. Total costs
include initial cost and maintenance cost. Initial cost of rigid pavement is generally high.
3.8 FUNCTIONS OF PAVEMENT COMPONENTS DESIGN FACTORS
FACTORS TO BE CONSIDERED IN DESIGN OF PAVEMENTS
Pavement design consists of two parts:
1) Mix design of materials to be used in each pavement component layer.

2) Thickness design of the pavement and the component layers
The various factors to be considered for the design of pavements are following:
1) Design wheel load

2) Sub grade soil
3) Climatic factors
4) Pavement component materials
5) Environmental factors

6) Special factors in the design of different types of pavements.
The thickness design of pavement primarily depends upon the design wheel load. Higher wheel
load obviously need thicker pavement, provided other design factors are the same while
considering the design wheel load, the effects of total static load on each wheel, multiple wheel
load are to be taken into account. As the speed increases, the rate of application of the stress is
also increased resulting in a reduction in the pavement deformation under the load, but on
uneven pavements, the impact increases with speed.
The properties of the soil sub grade are important in deciding the thickness requirement of
pavements. A sub grade with lower stability requires thicker pavement to protect it from traffic
loads. Apart from the design the pavement performance to a great extent depends on the sub
grade soil properties and the drainage. Among the climatic factors rain fall affects the moisture
conditions in the sub gradeand the pavement layers. The daily and seasonal variations in
temperature have significance in the design and performance of rigid pavements and bituminous
pavements.
The stress distribution characteristics of the component layers depend on characteristics of the
materials used. The fatigue behavior of these materials and their durability under adverse
conditions of weather also be given due consideration.
The environmental factors such as height of embankment and its foundation details, depth of
cutting, depth of the subsurface water table, etc. affect the performance of the pavement. The
choice of the bituminous binder and the performance of the bituminous pavements depend on the
variations in pavement temperature with seasons in the region. The warping stresses in rigid
pavements depend on the daily variations in temperature in the region and in the maximum
difference in the temperature between the top and bottom of the pavement slab.
In the case of semi-rigid pavement materials the formation of shrinkage cracks, pattern and the
mode of propagation and the fatigue behavior under such adverse conditions of hair cracks are to
be studied before arriving at a rational method of design for the semi-rigid pavements.

3.8.2 DESIGN WHEEL LOAD
The various wheel load factors to be considered in pavements design are:
1) Maximum wheel load

2) Contact pressure
3) Dual or multiple wheel loads and equivalent single wheel load
4) Repetition of loads
3.8.3 MAXIMUM WHEEL LOAD
The wheel load configurations are important to know the way in which the loads of a given
vehicle are applied on the pavement surface. For highways the maximum legal axle load as
specified by Indian roads congress is 8170 kg with a maximum equivalent single wheel load of
4085 kg total load influences the thickness requirements of pavements. Tire pressure influences
the quality of surface course. In fact, the magnitude of the vertical pressure at any depth of soil
sub grademass depends upon the surface pressure as well as on the total load.
3.8.4 CONTACT PRESSURE
At a greater depth the effect of tire pressure diminishes and the total load exhibits a considerable
influence on the vertical stress magnitudes tire pressure of high magnitudes therefore demand
high quality of materials in upper layers in pavements. The total depth of pavement is however
not influenced by the tire pressure the total load governs the stress on the top of sub grade within
allowable limits.
The stresses on the pavement surface under the steel tyred wheels of bullock cartsare very high.
This demands use of very strong and hard aggregate for the wearing surface of the pavement.
However the stresses at lower layers of pavement due to the bullock cart wheel are negligible
small as the gross load is very small.
Generally, the wheel loadis assumed to be distributed over a circular area but by measurements
of the imprints of tyres with different load and inflation pressures it is seen that contact areas in
many cases are elliptical in shape. Three terms in use with reference to tyre pressure are:
Tyre pressure

Inflation pressure
Contact pressure
Theoretically, all these terms should mean the thing.Tyre pressure and inflation pressure mean
exactly the same. The contact pressure is found to be more than tyrepressure when the tyre
pressure is less than 7kg/cm2 and it is vice-versa when the tyre pressure exceeds this value.
Contact pressure can be measured by the ratio of load on wheel to contact pressure area of
imprint.
The ratio of contact pressure to tyre pressure is defined as rigidity factor. Thus value of rigidity is
1.0 for an average tyre pressure of 7kg/cm2 this value is higher than unity for lower tyre pressure
and less than unity for tyre pressure higher than 7kg/cm2 the rigidity factor depends upon the
degree of tension developed in the walls of the tyre.
3.8.5 EQUIVALENT SINGLE WHEEL LOAD
To maintain the maximum wheel load within the specific limit and to carry greater load it is
necessary to provide dual wheel assembly to real axle of the road vehicle in doing so the effect
on the pavement through a dual wheel assembly is obvious not equal to two times the load on
one wheel. In other word the pressure at certain depth below the pavement surface cannot be
obtain by numerically adding the caused by any one wheel load. The effect is carried by single
and two times load carried by single and two times load carried by one wheel load the dispersion
is assumed to be at an angle of 45. In dual wheel load assembly be the clear gap between the
two wheels S be the spacing between the center of the wheels and a be the radius of the
circular contact area of each wheel, thenS=(d+2a).
Fig. 3.1 Distribution of ESWL

CHAPTER 4
DESIGN OF PAVEMENTS
4.1 GUIDELINES FOR THE DESIGN OF FLEXIBLE PAVEMENTS
The design of flexible pavement involves the interplay of several variables, such as the wheel
loads, traffic climate, and terrain and sub-grade conditions. With the rapid growth of traffic, the
pavements are required to be designed for heavy volume of traffic of the order of 150 million
standard axles.
4.2 DESIGN APPROACH AND CRITERIA
The pavement designs are given for sub gradeCBR values ranging from 2% to 10% and design
traffic ranging from 1 msa for an average annual pavement temperature of 30C using the
following simple input parameters, appropriate designs could be chosen for the given traffic and
soil strength.
1) Design traffic in terms of cumulative number of standard axles; and

2) CBR value of sub grade
4.3 TRAFFIC
The recommended method considers traffic in terms of the cumulative number of standard axles
(8160 kg) to be carried by the pavement during the design life. For estimating design traffic, the
following information is needed:
1) Initial traffic after construction in terms of number of commercial vehicles per day
(CVPD)
2) Traffic growth rate during the design life in percentage
3) Design life in number of years
4) Vehicle damage factor (VDF)

5) Distribution of commercial traffic over the carriageway.
4.4 TRAFFIC GROWTH RATE
Traffic growth rates should be estimated:
1) By studying the past trends of traffic growth, and

2) By establishing econometric models
If adequate data is not available, it is recommended that an average annual growth rate of 7.5%
may be adopted.
4.5 DESIGN LIFE
For the design of pavement, the design life is defined in terms of the cumulative number of
standard axles that can be carried before strengthening of the pavement is necessary.
It is recommended that pavements for national highways and state highways should be designed
for a life of 15 years. Expressways and urban roads may be designed for a longer life of 20 years.
For other categories of roads, a design life of 10 years may be adopted.
4.6 VEHICLE DAMAGE FACTOR
The vehicle damage factor is a multiple to convert the number of commercial vehicles of
different axle loads and configuration to the number of standard axles for the number of standard
axle load repetitions. It is defined as equivalent number of standard axles per commercial
vehicle. The VDF varies with the vehicle axle configuration, axle loading, terrain, type of road
and from region to region.
For designing a new pavement, the VDF should be arrived at carefully by carrying out specific
axle load surveys on the existing roads.

4.7 DISTRIBUTION OF COMMERCIAL TRAFFIC OVER THE
CARRIAGEWAY
A realistic assessment of distribution of commercial traffic by direction and by lane is necessary

as it directly affects the total equivalent standard axle load applications used in the design.
4.7.1 SINGLE LANE ROADS
Traffic tends to be more channelized on single-lane roads than two-lane roads and to allow for
this concentration of wheel load repetitions, the design should be based on total number of
commercial vehicles in both directions.
4.7.2 TWO-LANE SINGLE CARRIAGEWAY ROADS
The design should be based on 75% of the total number of commercial vehicles in both
directions.
4.7.3 FOUR-LANE SINGLE CARRIAGEWAY ROADS
The design of dual two-lane carriageway roads should be based on 75% of the number of
vehicles in each direction. For dual three-lane carriageway and dual four-lane carriageway, the
distribution factor will be 60% and 45% respectively.
The traffic in each direction may be assumed to be half of the sum in both directions when the
latter only is known. Where significant difference between the two streams can occur, condition
in the more heavily trafficked lane should be considered for design.
4.8 COMPUTATION OF DESIGN TRAFFIC
The design traffic is considered in terms of the cumulative number of standard axles to be carried
during the design life of the road.
N=365*[(1+r)n-1]*A*D*F/R

Where, N=the cumulative no. of standard axles to be created for in the design in terms of msa.
A=initial traffic in the year of completion of construction in terms of the no. of commercial
vehicles per day.
D=lane distribution factor
F=vehicle damage factor
N=design life in years
R=annual growth rate of commercial vehicles
The traffic in the year of completion was estimated using the following formula:
A=P(1+r)^n
Where, P=number of commercial vehicles as per last count.
X=number of years between the last count and the year of completion of construction.
4.9 LOCATION OF FLEXIBLE PAVEMENT
The project road is situated near Sitapur area.
Lucknow Sitapur BOT (Toll) Project on NH-24
Project Brief:-
National Highway NH-24 is one of the prime transport corridors in the state of
Uttar Pradesh. It connects the state Capital Lucknow with the National Capital
Delhi and industrial town and cities like Sitapur. Bareilly, Moradabad and
Ghaziabad of Uttar Pradesh. The highway also connects with NH-1, NH-25, NH-
58, NH-74 and NH-87. Thus, our project LUCKNOW-SITAPUR

EXPRESSWAYS LIMITED (LSEL) is a major Project on the NH-24. Its a road
routes in the National Highway Network, connects Lucknow-Sitapur and northern
regions of the country. The road passes through several major cities and industrial
centers along its way. It serves as the major trunk road in the country and carries a
sizeable amount of intra-state and inter-state traffic.
The widening and converting Lucknow-Sitapur Section (Km 413.200 to

Km488.270) of NH-24 into a 4 lane dual carriageway is now being implemented
on Build, Operate and Transfer (BOT) basis.
The project is on the existing road segment from Km413.200 to Km.488.270.The

Concession Agreement envisages that after completion of the widening, the
roadway width in the main carriageway from stretch Km413.200 to Km 488.270
will include.
4 lane dual carriageway ,

1.5 M wide paved shoulder with 2.0 m wide earthen shoulder.
Median of 4.50M & 1.20M respectively.
Salient features of concession Agreement (LSEL) is:-
Sr. Description Date

1. Project Length 75.070 Km.
(Km.413.200 to Km. 488.270)
2. Name of Concessionaire M/s Lucknow-Sitapur Expressways Ltd.
3. Name of Independent Engineer Theme Engineering Services Pvt. Ltd.
4. Date of Letter of Acceptance 9th September 2005
5. Date of Concession Agreement 23rd December 2005
6. Commencement date of 22nd June 2006
concession

7. Scheduled End of Concession 21st June,2026
period
8. Concession Period 20 Years including construction period
9. Construction Period 36 months
10. Total Project Cost 450.41 Cr.
11. EOT-1 for 12 month Up to 20.06.2010
12. EOT-2 for 12 month Up to 19.06.2011
13. EOT-3 Up to 30.11.2011
14 EOT-4 UP to 10.06.2012
11. Location of Toll Plazas *Toll Plaza I : Km. 420
*Toll Plaza II: Km. 467
12. Toll Collection Started by 17th October,2011
Concessionaire
The project details are as follows (Highlights) :

SI. Description Details
Strengthening and widening of existing 2-lane road to 4-

Scope of lane Dual Carriageway from Km 413.200 Km488.270 of
1.
construction NH-24(Lucknow Sitapur-Section) in the state of Uttar
Pradesh on Build, Operate, Transfer (BOT) basis.
2. Project Length 75.070 km
1) 4-lane divided carriageway with raised median

Pavement 2) Total length of flexible pavement-74.561 km
3.

Total length of rigid pavement-
Chainage-420.00 KM-0.740 km
Chainage-467.00 KM-0.630 km
1. Ch:413.252
2. Ch:415.210
Intersections/Ju 3. Ch:418.173
4.
nctions 4. Ch:445.850
5. Ch:481.100
Minor-04 Nos.
KM 420/1
KM 457/1
5. Bridges KM 461/1
KM 468/2
Major-01 Nos.
KM 432/1-Goan bridge
Pipe Culverts-40 nos.
6. Culverts Slab culverts-26 nos.
Box culverts-16 nos.
7. Toll Plazas 2 No.-1 no@Ch. 420 Km & 1 No.@ CH 467 Km
8. Underpasses 05 Nos.
Bus Bays: 06 nos.
KM 423.100
KM 428.500
KM 435.000
KM 446.000
9. Other facilities KM 469.000
KM 479.200
Truck Parking/Laybys :03 no
KM 416.518
KM 445.231
KM 484.240
As per DPR minimum 5 underpasses are to be constructed along the project road.
Construction work of 2 underpasses is completed and the remaining 3 have been
deferred for the time being due to Land Acquisition problem.

FINANCIAL PLAN
Source of Financing
The Project is proposed to be financed in the Rs in % of
following manner Crore Total
Promoters equity 119.33 26.50%
NHAI Grant 117.08 26.50%
Rupee Term Loan 214.00 47.50%
Total 450.41 100%
Commencement of Operation & Maintenance Period

The Concessionaire is completed of the Project Highway as on completion date,
thereafter; Concessionaire started the Toll Operation and Maintenance activities of
the project Highway.
Operation and Maintenance Phase Responsibilities
Maintenance will include clearing, replacement of equipment/consumables,
roadside facilities, horticultural maintenance and repairs to equipment, pavements,
Bridges, structures, HTMS and other civil maintenance works. Maintenance will
not include the Extension of any existing pavement, bridges, structures and other
civil works of the Project except pending construction work.
Types of Maintenance
The road maintenance can be divided in to four basic types.
1. Routine Maintenance
2. Preventive Maintenance
3. Periodic Maintenance
4. Special repairs
Toll Rates
Date of issue of fee Notification Date of Approved fee Notification by

Authority
17-10-2011 17-10-2011
Date of revision for new toll rates effective from 12-09-2013 ( Sep.2013 to
Sep.2014) **
Class Single Return
Car, Passenger van or jeep 36 54
Light Commercial Vehicle (LCV)
63 95
including mini Bus
Truck/Bus 127 190
Multi Axle Vehicle (>2 axle) 204 306
Earth-moving equipments and
272 408
heavy construction machinery
** Toll rates are subject to revise on September month of every year but can
be revise on special privilege.
Toll Concession:-
A. Toll concession scheme available for Local Traffic
Monthly pass
Local Personal Traffic (LPT) Pay 25 % of tariff
Local Commercial Traffic (LCT) Pay 50 % of tariff
Toll Exemption:-
Toll exemption is applicable as per the guideline given by NHAI.
4.9.1 RECOMMENDED METHOD OF FLEXIBLE PAVEMENT DESIGN
In this CBR method of pavement design by cumulative standard axle load has been used.
4.9.2 DATA AVAILABLE
Traffic growth rate - 7.5%
Design life 7 years
Lane distribution factor 0.75
Vehicle damage factor 4.5

CBR value 4%
On the behalf of available data value was calculated and this is near about 3.
4.9.3 CALCULATION OF PAVEMENT THICKNESS
For value 3 and CBR value 4% calculated pavement thickness is 555

mm.
Pavement composition is-
Bituminous surface
BC 25 mm
DBM 50 mm
Granular sub base 180 mm
Wet mix macadam 300 mm
4.9.4 PAVEMENT COMPOSITION
FIG. 4.1 Effect of loading on pavement layers

4.10 GUIDELINES FOR THE DESIGN OF RIGID PAVEMENTS
4.10.1 GENERAL DESIGN CONSIDERATIONS
Comment concrete pavements represent the group of rigid pavements. Here the load carrying
capacity is mainly due to the rigidity and high modulus of elasticity of the slab level i.e; slab
action.
Westgaard considered the rigid pavement slab as a thin elastic plate resting on soil subgrade
which is assumed as a dense liquid. Here it is assumed that the upward reaction is proportional to
the deflections i.e; p=k5 where the constant k is defined as modulus of subgrade reactions. The
unit of k is kg/cm^2 percm deflection.
The modulus of subgrade reaction, k is proportional to displacement. The displacement level is

taken as 0.125. If p is pressure sustained in kg/cm^2 by the rigid plate of diameter 75 cm at a
deflection of 0.125 cm, the subgrade reaction k is given by
K = p/0.125 kg /cm^3
4.10.2 RELATIVE STIFFNESS OF SLAB TO SUBGRADE
A certain degree of resistance to slab deflection is offered by the subgrade. This is dependent
upon the stiffness or pressure deformation properties of the subgrade material. The tendency to
the slab to deflect is dependent upon its properties of flexural strength.
The resultant deflection of the slab which is also the deformation of the subgrade is a direct
measure of the magnitude of the subgrade pressure. The pressure deformation characteristics of
rigid pavement is thus a function of relative stiffness of slab to that of subgrade.
Westergaard defined this term as the radius of relative stiffness
= [Eh3/12 k(1-m2)]1/4

Here,
L= radius of relative stiffness, cm
E= modulus of elasticity of cement concrete kg/cm2
M= Poissons ratio for concrete = 1.5
H= slab thickness
K= subgrade modulus or modular of subgrade reaction, kg/cm2
4.10.3 CRITICAL LOAD POSITION
Since the pavement slab has finite length and width, either the character or intensity of maximum
stress induced by the application of a given traffic load is dependent on the location of the load
on the pavement surface.
There are three typical locations namely the interior, edge and corner, where differing conditions
of slab continuity exists. These are termed as critical load positions.
4.10.4 INTERIOR LOADING
When load is applied in the interior of the surface at any place remote from all the edges.
4.10.5 EDGE LOADING
When load is applied on an edge of the slab at any place remote from a corner.
4.10.6 CORNER LOADING
When the center of load application is located on the bisectors of the corner angle formed by two
intersecting edges of the slab, and the located area is at the corner touching the two edges.
4.10.7 EQUIVALENT RADIUS OF RESISTING SECTION
Consider the case of interior loading, the maximum bending moment occurs at the loaded area
acts radially in all directions. With the load concentrated on a small area of the pavement, the
question arises as to what sectional area of the pavement is effective in resisting the bending

moment. According to westergaard, the equivalent radius of resisting section is approximated, in
terms of radius load distribution and slab thickness.
4.10.8 WHEEL LOAD STRESSES
A.T.Goldbeckindicated that many concrete failed at the corners of the slab. Gladbecks formula
for stress due to corner load is given by
S= 3P/h 2
Here, S = stress due to corner load, kg/cm2
P = corner load assumed as a concentrated point load
H = thickness of slab
4.10.9 WESTERGAARD STRESS EQUATION FOR WHEEL LOADS
The cement concrete slab is assumed to be a homogeneous, thin plastic with subgrade reaction
being vertical and proportional to deflection. He considered three typical regions of cement
concrete pavement slab for the analysis of stresses, as the interior edges and the corner regions.
4.11 EVALUATION OF WHEEL LOAD STRESSES FOR DESIGN
Westergaard wheel load stress equations for interior, edge and corner have been modified by
various investigators based on their research work on cement concrete pavements slabs. The
stresses at the edge and corner regions are generally found to be more critical for the design of
rigid pavement for highways. The Indian Roads Congress recommended the following two
formulas for the analysis of road stresses at the edge and corner regions are generally found to be
more critical for the design of rigid pavement for highways. The Indian Roads Congress have
recommended the following two formulas for the analysis of load stresses at the edge and corner
regions and for the design of rigid pavements.
1) Westergaards edge load stress formula, modified by Teller and Sutherland for the finding
the load stress S in critical edge region.

Se = 0.529P(1+5.4m)(4 logl/b)+logb 0.4048)/h2
2) Westergaard corner load stress analysis modified by Kelly for finding the load stress S at
the critical corner region
Sc = 3P[1-(a 21/2)1/2]/h2
Where,
Se = load stresses at edge region, kg/cm2
Sc = load stresses at corner region, kg/cm2
P = design wheel load, kg
h = thickness of CC pavement slab, kg/cm2
m = modular of elasticity of the CC, kg/cm2
l = radius of relative stiffness, cm
b = radius of equivalent distribution of pressure, cm
4.11.1 TEMPERATURE STRESSES
Westergaards concept of temperatures tresses:
Temperature stresses are developed in cement concrete pavement due to variations in slab
temperature. The variation in temperature across the depth of the slab is cause by daily variation
whereas an overall increase or decrease in slab temperature is caused by seasonal variation in
temperature.
During the daily the top of the pavement slab still remains relatively colder. The maximum
difference in temperature between the top and bottom of the pavement slab may occur at some
period after mid-noon. This causes the slab to warp or bend, as the warping is resisted by the
self- weight of the slab, warping stresses are developed late in the evening, the bottom of the slab
gets heated up due to heat transfer from the top and as the atmospheric temperature falls, the top
of the slab becomes colder resulting in warping of the slab in the opposite direction and there is a
reversal in warping stresses at the different regions of the slab. Thus the daily variation in

temperature causes warping stresses in reverse directions at the corner, edge and interior regions
of the slab.
During summer season as the mean temperature of the slab increases, the concrete pavement
expands towards the expansion joints. Due to frictional resistance at the interface, compressive
stress is developed at the bottom of the slab as it tends to expand. Similarly during winter season,
the slab contracts causing tensile stress at the bottom due to frictional resistance again opposing
the movement of slab. Thus frictional stresses are developed due to seasonal variation in
temperature. The frictional resistance will be stress will be zero at the free ends and at expansion
joints and increases up to a maximum value towards the interior and there after remains constant.
Temperature thus tends to produce two types of stresses in concrete pavement. These are
1) Warping stresses
2) Frictional stresses
4.11.2 WARPING STRESSES
Where the top and bottom surfaces of a concrete pavement simultaneously possessdifferent
temperatures, the slab tends to warp downward or upward inducing warping stresses.
The difference in temperature between the top and bottom of the slab depends mainly on the slab
thickness and climatic conditions of the region.
By the time the top temperature increases to t1 degrees, the bottom temperature may be only t2
degrees and the difference between the top and the bottom of the slab would be (t1 t2) = t
degrees.
Assuming straight line variation in temperature across the pavement depth, the temperature the
temperature at mid depth or average temperature of slab would be (t1 + t2)/2.
Introducing the effect of Poissons ratio the stress at the interior, region in longitudinal and
transverse directions as given by Bradburys are expressed by the following equations.
St(t) = Eet[(Cx + mcy/1 m2]/2
Here,

St(t) = warping stress at interior, kg/cm2
E = modulus of elasticity of concrete, kg/cm2
E = thermal coefficient of concrete / C
T = temperature difference between top and bottom of the slabin C
Cx = coefficient based on Lx/l in desired direction
4.11.3 FRICTIONAL STRESSES
Due to uniform temperature rise and fall in the cement concrete slab, there is an overall
expansion and contraction of the slab. Since the slab in contact with soil subgrade or the sub
base, the slab movements are restrained due to the friction between the bottom layer of the
pavement and the soil layer. This frictional resistance therefore tends to prevent the movements
thereby inducing the frictional stress in the bottom fiber of the cement concrete pavement.
Stresses in slabs resulting due to this phenomena vary with slab length. In short slab stress
induced due to this is negligibly small whereas in long slabs, which would undergo movements
of more than 0.15 cm higher amount of frictional stress develops.
Equating, total force developed in the cross section of concrete pavement due to movement
and frictional resistance due to subgrade restraint in half the length of the slab.
Here,
Sf = unit stress developed in cemnent concrete pavement, kg/cm2
W = unit weight of concrete, kg/cm2
f = coefficient of subgrade restraint
L = slab length, metre
B = slab width, metre
4.11.4 COMBINATION OF STRESSES
It is necessary to consider the conditions under which the various stresses in cement concrete
pavements could combine to give the most critical combinations.

The following conditions are considered to provide the critical combinations.
4.11.5 DURING SUMMER
The critical combinations at interior and edge regions during mid-day occur when the slab tends
to warp downward. During this period maximum tensile stress is developed at the bottom fiber
due to warping and this is cumulative with tensile stress due to the loading. However the
frictional stress is compressive during expansion. The load stress at edge region is higher than
the interior.
Critical combination of stresses = (load stress + warping stress frictional stress), at edge region.
4.11.6 DURING WINTER
The critical combination of stresses at the above regions occurs at the bottom fiber when the slab
contracts and the slab warps downward during the mid-day. The frictional stress is tensile during
contraction.
The critical stress combination = (load stress + warping stress + frictional stress), at edge region.
Since, the differential temperature t is lower magnitude during winter than in summer, the
combination (1) may be worst for most of the regions in this country.
At corner regions, the critical combination occurs at the slab, when the slab warps upwards
during the mid-nights. There is no frictional stress at the corner regions.
4.12 DESIGN OF JOINTS IN CEMENT CONCRETE PAVEMENTS
Various types of joints provided in cement concrete pavements to reduce the temperature stresses
are expansion joints, contraction joints and warping joints. If expansion and contraction joints
are properly designed and constructed, there is no need of providing warping joints, in addition.
Expansion joint spacing is designed based on the maximum temperature variations expected and
width of joint. The contraction joint spacing design is governed by the anticipated frictional
resistance and allowable tensile stress in concrete during the initial curing period, or the amount
ofreinforcement, if any. The spacing between the expansion joints is so adjusted that the

contraction joints have equal spacing. Dowel bars are provided at expansions joints and
sometimes at contraction joints also. The size and spacing of the dowel bars are designed and are
also governed by standard specification based on practical considerations. Longitudinal joints in
cement concrete pavements are constructed with suitable the bars. The design considerations
include diameter, spacing and length of the bars.
4.12.1 SPACING OF EXPANSION JOINT
The width or the gap in expansion joint depends upon the length of the slab. Greater the distance
between the expansion joints, the greater is the width required of the gap for expansion. The use
of wide expansion joint space should be avoided as it would be difficult to keep them properly
filled in when the gap widens during winter seasons. The dowels would develop high bending
bearing stresses with wider openings. It is recommended not to have a gap more than 2.5 cm in
any case. The IRC has recommended that the maximum spacing between expansion joints should
not exceed 140 m for rough interface layer.
If l is the maximum expansion in a slab of lengthLewith a temperature rise from T1 and T2.
L = Le. C(T2 T2)
Le is given by
Le = 1/100/C/(T 2 T1)
4.12.2 SPACING OF CONTRACTION JOINTS
The slab contracts due to the fall in slab temperature below the construction temperature. Also
during the initial curing period, shrinkage occurs in cement concrete. This movement is resisted
by the sub grade drag or friction between the bottom fibers of the slab and the sub grade; if L is
the slab length in meter, the maximum stress occur at half length.
Total frictional resistance up to distance Lc/2 = W*b*(Lc/2)*(h/100)*f
Allowable tension in cement concrete = Sc * h * b * 100
Equating the above two values,
Lcb h f/200 = 100Sch b

Length of slab to resist the frictional drag, i.e; spacing of contraction joints,
Lc= (2 Sc/ Wf) * 10 4
Here, Lc = slab length or spacing between contraction joints, m
H = slab thickness, cm
F = coefficient of friction, (maximum value = 1.5)
W = unit weight of cement concrete, kg/m3
Sc= allowable stress in tension in cement concrete, kg/cm2
Since the contraction and shrinkage cracks develop mainly during initial period of curing, a very
low value of Scis considered in design. The permissible stress is generally kept as low as about
0.8kg/cm2
4.13 DESIGN OF DOWEL BAR
Dowel bar of expansion joints are mild steel round bars of short length. Half-length of this
bar is bonded in one cement concrete slab and the remaining portion is embedded in adjacent
slab, but is kept free for the movement during expansion and contraction of the slab. The
dowel bars allow opening and closing of the joint, maintaining the slab edges at the same
level, and the load transferredis effected from one slab to the other.
4.14 DESIGN OF TIE BARS
Tie bars are used across the longitudinal joints of cement concrete pavements. Tie bars assure
two adjacent slabs to remain firmly together. These bars are designed to withstand tensile
stresses, the maximum tensile force in tie bars being equal to the force required to overcome
frictional force between the bottom of the adjoining slab and soil subgrade. The force is

considered from the joint location to the subsequent joint or free edge. Thus considering one
meter length of joint,
As Ss= b. h. W. f/100
As = b. h. W. f/100/Sd
Where As = area of steel per meter length of joint, cm2
B = distance between the joint and nearest free edge, m
H = thickness of pavement
F = coefficient of friction between pavement and sub grade
W = unit weight of cement concrete, kg/m3
Ss = allowable working stress in tension for steel, kg/m2
4.14.1 LENGTH OF TIE BAR
The total length of tie bar should be at least twice the length of embedment required on each
slab to develop bond strength equal to the working stress of the steel.
This is obtained from the consideration that the total tensile force developed in tie bar should
not exceed the bond strength between the tie bar and the concrete. Therefore considering one
side of the longitudinal joints,
AsLs = L1.P.Sb/2
L1 = 2.A.Ss/P/Sb
Substituting As = 3.14 d2/4 and P = 3.14 d
Lf =d.Sf/2/Sb
Here,
Lf/2 = length of tie bar on one side of slab, cm or half-length of tie bar
Ss = allowable stress in tension, kg/cm2

Sb = allowable bond stress in concrete, kg/cm2
As = cross sectional area of one tie bar
P = perimeter of tie bar, cm
D = diameter of tie bar, cm
4.15 IRC RECOMMENDATIONS FOR DESIGN OF CONCRETE

PAVEMENTS
a) DESIGN PARAMETERS
1) The design wheel load is taken as 5100kg with equivalent circular area of 15cm and a
tyre inflation pressure ranging from 6.3 to 7.3 kg/cm2. The traffic volume is projected
for 20 years period after construction using the relation:
Ad = P[1+r](n+20)
Where, Ad = number of commercial vehicles per day
P = number of commercial vehicles per day at last count
R = annual rate of increase in traffic intensity
N = number of years between traffic count and the commissioning of new

cement concrete pavement
2) The modulus of sub gradereaction K is determined using standard plate of 75 cm

diameter at 0.125 cm deflection. If 30 cm plate diameter is used, the K value obtained
at 0.125 deflections is multiplied by .5 in order to estimate the K-value of standard
plate diameter. The minimum K-value of 5.5 kg/cm2is specified for laying cement

concrete pavement. If the K value is lower, suitable sub-base course may be
provided to increase the K-value.
3) The flexural strength of cement concrete used in the pavement should not be less than
40kg/cm2. As a general guidance the minimum compressive strength on 15 cm cubes
may be taken as 280 kg/cm2at 28 days and mix design strength of 315 to 350 kg/cm2,
depending upon the degree of quality control. The modulus of elasticity, E and
Poissons ratio, m may be determined experimentally. The suggested E-value is
300000 kg/cm2 and m = 0.15. The coefficient of thermal expansion of concrete may
be taken as 0.00001 /C for design purposes.
b) CALCULATION OF STRESSES
1) The wheel load stresses at edge region calculated for the designed slab thickness as
per Westergaards analysis modified by Teller and Sutherland.
2) Temperature stresses at edge region is calculated as per Westergaards analysis using

Bradburys coefficient.
3) Wheel load stress at corner region is calculated as per Westergaards analysis,

modified by Kelly
c) DESIGN STEPS FOR THICKNESS
1) The width of slab is decided based on the joint spacing and lane width.
2) The length of CC slab is equal to the spacing of the contraction joints, Lc. This is
designed for plan CC pavement. At times reinforcement is provided at the contraction
joints for the assumed trial thickness of the slab. However the slab length could
confirm to the recommendations on spacing of joints.

3) A plain thickness value of the slab is assumed for calculating stresses. The warping
stress at edge region is calculated and this value is subtracted from the allowable
flexural stress in concrete to find the residual strength in the pavement to support
edge loads.
4) The load stress in edge region is found using stress chart. The available factor of
safety in edge load stress with respect to the residual strength is found. If the value of
factor of safety is less than 1 or is far excess of 1, another trial thickness of slab is
assumed and the calculations are repeated till the factor of safety works out to 1 or
slightly higher value for the design thickness h cm.
5) The total stresses at corner due to wheel load and warping is checked using stress
chart for the thickness h cm. If this stress value is less than allowable, flexural stress
in concrete, the slab thickness, h is adequate or else the thickness may be suitably
increased.
6) The design thickness, h is adjusted for the traffic intensity or classification at the end
of design life and using the adjustment value to obtain the final adjusted slab
thickness.
d) SPACING OF JOINTS
1) The maximum spacing recommended for 25 mm wide expansion joints is 140 m

when the foundation is rough, for all slab thickness. When the foundation surface
is smooth the maximum spacing may be 90 m for slab thickness upto 20 cm and
spacing of 120 m for slab thickness 25 cm, when the pavement is constructed in
summer however, when the pavement is constructed in winter, the above spacing
may be restricted to 50 and 60 m respectively.

2) The maximum contraction joint spacing may be kept at 4.5 m in unreinforced
slabs of all thickness. In the reinforced slabs, the contraction joint spacing may be
13 m for 15 cm thick slab with steel reinforcement of 2.7 kg/m2and 14 m spacing
for 20 cm thick slabs with steel reinforcement of 3.8 kg/m2
e) DESIGN OF DOWEL BARS
The dowel bar system may be designed on the basis of Bradburys analysis for load
transfer capacity of a single dowel bar in shear, bending and bearing in concrete.
Dowel bars do not function satisfactorily in thin slabs and therefore dowel bars are
provided in slab of thickness 15 cm or more. IRC recommends 2.5 cm diameter dowel
bars of length 50 cm in the case of 15 cm thick slabs and spaced at 30 cm in the case of
20 cm thick slabs, the design load being 5100 kg.
f) DESIGN OF TIE BARS
Tie bars are designed for longitudinal joints. Permissible bond stress in deformed bars is
24.6 kg/cm2and that in plain tie bars is 17.5 kg/cm2. Allowable working stress in tensile
steel is taken as 1400 kg/cm2.

Fig. 4.2 Tie bars
g) DESIGN OF REINFORCEMENT
Reinforcement in CC pavements are intended to prevent deterioration of the cracks and

not to increase the flexural strength of uncracked slab. The area of longitudinal and
transverse steel required per metre width or length of slab is computed from the formula:
A = L.f.w/2S
Where, A = area of steel required per metre width or length of the slab, cm2
L = distance between free transverse joints or free longitudinal joints, m

F = coefficient of friction between pavement and subgrade, usually taken as 1.5
S = allowable working stress in steel, usually taken as kg/cm2 or 50 to 60 percent of

minimum yield stress, kg/cm2
W = weight of unit area of pavement slab, kg/m2

The reinforcement may be placed 5 cm below the surface of the slab and is continued
across dummy groove joints to serve the purpose of tie bars. At all full depth joints and
edges, the reinforcement is kept at least 5 cm away from the face of joint or edge.
4.16 LOCATION OF RIGID PAVEMENT
Khurram Nagar area, Lucknow
4.16.1 DATA AVAILABLE
Width of expansion joint gap = 2.5 cm
Maximum variation in temperature between summer and winter = 35C
Thermal coefficient of concrete = 10*10-6/C
Allowable tensile stresses in CC during curing = 0.8 kg/cm2
Coefficient of friction = 1.5
Unit weight of CC = 2400 kg/cm3
Flexural strength of concrete = 40 kg/cm2
E value of concrete = 3*10 5 kg/cm2
value= 0.15
Design load transfer through dowel system = 40%

Permissible flexural transfer in dowel bar = 1000 kg/cm2
Permissible shear stress in dowel bar in concrete = 100 kg/cm2
Permissible tensile stress in steel (tie bar) = 1400 kg/cm2
Permissible bond stress in deformed tie bars = 24.6 kg/cm2
Temperature differential in the region:

Table.4.1 Temperature variations in slab
Slab thickness, cm 15 20 25
Temperature 14.6 15.8 16.3
differential in slab in
the region, C
4.16.2 DESIGN
A. Joint spacing
D = joint = 2.5/2 = 1.25 cm
Spacing of expansion joint Ls = D/100C (T2 T1) = 1.25/100*10*10-6 *35 = 35.7 M
It is less than maximum specified spacing of 140 m and hence acceptable, contracting joint
spacing in plain CC,
Lc = 2Sc*10 4 /W*f = 2*0.8*104 /2400*1.5 = 4.45 m

It is less than maximum specified spacing of 4.5 m and hence acceptable.
Therefore provide contraction joint at 4.45 m spacing and expansion joint at every 8th such joint
e.g.4.45*8 = 35.5 (instead of 35.7)
B. Pavement slab thickness
Assuming trial thickness of slab = 20 cm
Radius of relative stiffness, l = [Eh3/12K(1-Mu2)]1/4
= [3*105*20 3/12*8(1-0.152)]1/4 = 71.1 cm
Lx/l = 445/71.1 = 6.26
Ly/l = 350/71.1 = 4.92
Warping stress coefficient Cx at Lx/l of 6.26 = 0.92
At L y/l = 4.92, Cy = 0.72 <Cx
Temperature differential for 20 cm thick slab = 15.8C
Warping stresses at edge, Ste = C x.E.e.t/2
= 0.92*3*10 5*10*10-6*15.8/2 = 21.8 kg/cm2
Residual strength in concrete slab at edge region = 40.0 21.8 = 18.2 kg/cm2
Load stress in region, using IRC stress chart, corresponding to
H = 20, K = 8, Se = 27.5 kg/cm2
Factor of safety available = residual strength/edge load stress = 18.2/27.5 = 0.66
As the factor of safety is less than 1.0, it is unsafe therefore assume a higher slab thickness say h
24 cm.

L = [3*10 5*243/12*8*(1-0.152)]1/4 = 81.53 cm
Lx/l = 445/81.53 = 5.46
Cx = 0.80, Cy at Ly/l of 4.29 = 0.6
Temperature differential for 24 cm thick slab (by interpolation) = 16.2C
Ste = *3*10 5*10*10-6 *16.2*0.8 = 19.44 kg/cm2
Residual strength at the edge = 40.0 19.44 = 20.56 kg/cm2
Load stress at edge, h = 4, K = 8, Se = 19.2 kg/cm2
Factor of safety available = 20.56/19.2 = 1.07 which is safe and accepted value
Therefore we provide a tentative design thickness of 24 cm.
Check for corner load stress: using IRC stress chart for h = 24, K = 8 the value of Se = 23.0
kg/cm2
Corner warping stress Ste = [E.e.t/3(1-mu)](a/l)1/2
= 7.1 kg/cm2
The worst combination of stresses at corner is 23+7.1 = 30.1 kg/cm2< 40 kg/cm2and hence the
design is safe.
Adjustment for traffic intensity
As = p[(1+r)](n+20)
Assuming the growth factor r =7.5% and the number of years after the last count before
adjustment factor is +2 cm.
Therefore the revised thickness of the slab = 24+2 = 26 cm
C. Dowel bars
Assuming dowel bar diameter = 2.5 cm

Joint width, D = 2.5 cm
For equal capacity in bending and bearing
Ld = 5d [F1/Fb *(Ld + 1.5 D/Ld +8.8 D)]1/2
= 5*2.5[1400/100 *(L d + 1.5* 2.5/Ld +8.8*2.5)]1/2
By substituting different values of Ld by trials, the value of Ld is found to be 42.2 cm,
Length of dowel bar = Ld+ D = 42.2 + 2.5 = 44.7 cm
Therefore provide 45 cm long dowel bars of diameter 2.5 cm
Actual value = 45 2.5 = 42.5 cm
Load transfer capacity of single dowel bar:
P (shear) = 0.785 d2 Fs
= 0.785*2.5*25*1000 = 4906 kg
P (bearing) Fb *Ld2 *d/(12.5(Ld + 1.5D)) = 100*42.5*2.5/12.5(42.5 + 1.5 * 2.5)
= 781 kg
Taking the lowest value for design, P (design)= 678 kg
Load capacity factor required:
Load capacity of the dowel group = 5100 * 40/100 = 2040 kg
Capacity factor required = 2040/678 = 3
Spacing of dowel bars:
Radius of relative stiffness for revised slab thickness of 24 cm
L = [3*10 5*263 /12*8(1-0.15 2)]1/4 = 86.6 cm
Effective distance up to which there is load transfer = 1.8

= 1.8*86.6 = 155.9 cm
Assuming a trail spacing of 35 cm between the dowel bar, the capacity available for the
group
= 1+ 155.9-35/155.9 70/155.9 + 155.9-105/155.9 + 155.9 140/155.9
= 2.77 <the required value of 3
Assume dowel bar spacing of 30 cm
Capacity factor = 1 + 155.9 30/155.9 + 155.9 60/155.9 + 155.9 90/155.9 + 155.9

150/155.9 = 3.11
Fig. 4.3 Dowel bars
As this value is greater than the required capacity factor of 3, 30 cm spacing of the dowel is
adequate therefore provide 2.5 cm diameter, dowels bars at expansion joints, of total length
45 cm at spacing of 30 cm centers.
D. Tie bars
Area of steel per meter length longitudinal jhoint,

As = b.f.h.W/100Ss = 3.5*1.5*26*2400/100*1400 = 2.34 cm2 / meter length
Assuming 1 cm diameter of the bars, cross sectional area of each tie bars as = 0.785 cm2
Perimeter of tie bar = 3.14 cm
Number of tie bars required per meter length of joint = As/as = 2.34/0.785 = 2.98
Spacing of tie bars = 100/2.98 = 33.5 cm
Provide a spacing of tie bar, say 33cm
Length of plain tie bar, L f = d.Ss/2Sb = 1*1400/2*24.6 = 28.5 cm
The length of tie bar may be increased by 5 cm for tolerance in placement
Therefore provide 1 cm diameter deformed tie bars, 34 cm in length at spacing of 33 cm.

CHAPTER 5
COMPARISON
5.1 COMPARISON OF FLEXIBLE AND RIGID PAVEMENTS
5.1.1 COMPARISON OF STRUCTURAL DESIGNS
The main point of difference in the structural behavior of rigid pavements as compared to the
flexible pavement is that the critical condition of stress in the rigid pavement is the maximum
flexural stress occurring in the slab due to wheel load and the temperature changes whereas in
the flexible pavement it is the distribution of the compressive stresses. As the rigid pavement
slab has tensile strength, tensile stresses are developed due to the bending of the slab under
wheel load and temperature variations thus the types of stresses developed and their distribution
within the cement concrete slab are quite different. The rigid pavement does not deformed to the
shape of lower surface as it can bridge the minor variations of the lower layer.
5.1.2 ESTIMATION AND COMPARISON OF COSTS
Total cost includes initial cost and temperature and maintenance cost.
Initial cost of rigid pavement is generally high.
According to our project the cost of flexible pavement is 61 lacs per km per lane.
The cost of rigid pavement is 150 lacs per km per lane.
5.1.3 CROSS SLOPE
For rigid pavement cross slope provided for heavy rainfall is 2% and for lights rainfall is 1.7%
generally camber provided is of straight line shape.
For flexible pavement cross slope provided for heavy rainfall is 2.5% and for light rainfall is
2.0% generally camber provided is of parabolic or elliptical shape.
5.1.4 RIDING QUALITY AND COMFORT
The rigid pavement gives much better riding quality and comfort than the flexible pavements.

Night visibility very much depends upon the light reflecting characteristics of the pavement
surface. Rigid pavement or white pavement surface gives good visibility at night particularly
during rains, and they produce glare and eye strain during bright sunlight.
On the other hand black top pavement surface provides very poor visibility at nights, especially
when the surface is wet.
5.1.5 CONSTRUCTION PROCEDURE FOR FLEXIBLE PAVEMENT
The bituminous concrete is the highest quality of construction in the group of black top surfaces.
Being of high cost specifications, the bituminous mixes are properly designed to satisfy the
design requirements of the stability and durability. The mixture contains dense grading of coarse
aggregate, fine aggregate and mineral filter coated with bituminous binder. The mix is prepared
in a hot mix plant the thickness of bituminous concrete layer depends on traffic quality of base
course.
Specification of material and construction steps for bituminous concrete surface is given below:
5.2 SPECIFICATION OF MATERIALS
5.2.1 BINDER
Bituminous of grade 30/40, 60/70 or 80/100 may be choosen depending upon the climatic
condition of locality.
5.2.2 AGGREGATE AND FILLER
Coarse aggregate should fulfill the following requirement
Aggregate Impact, maximum percent : 30
Los Angeles abrasion value, max percent : 40
Flakiness index value, max percent : 25

Stripping at 40C after 24 hours, max percent : 25
5.2.3 SOUNDNESS
Loss with sodium sulphate in 5 cycles, max percent: 12
Loss with magnesium sulphate in 5 cycles, max percent: 18
5.2.4 BITUMINOUS CONCRETE MIX
Marshall Stability test-number of blows to be applied on side of specimen: 50
Marshall Stability value, min. kg: 340
Marshall flow value: 0.25 mm units: 8 to 16
Voids in mix percent: 3 to 5
Voids filled with bitumen percent: 75 to 85
5.3 CONSTRUCTION PROCEDURE FOR RIGID PAVEMENTS
The construction of cement concrete pavement is dealt under the following groups:
1) Construction of pavement slabs

2) Construction of joints
5.4 CONSTRUCTION OF CEMENT CONCRETE PAVEMENT SLAB
Various specification for construction of cement concrete pavements are listed below:
Cement layer
Rolled grouted layer
Cement concrete layer
In cement grouted layer, open graded aggregate mix with minimum sizeof aggregates as 18 to 25
mm is laid on the prepaid subgrade and the aggregates are dry rolled. The loose thickness is
compacted to provide 80 percent of rolled thickness the grout made of coarse sand, cement and

water is prepared. The proportion of cement to sand is taken as 1:1.5 to 1:2 to provide proper
fluidity to the grout, wetting agent is also added to the mix. The grout is also applied on the
surface and is allowed to seep through the aggregate matrix.
In rolled concrete layer, lean mix concrete is used. Lean mix of aggregate, sand, cement and
water is prepared and laid on the prepared, subgrade or sub-base course. The rollingis similar to
WBM construction. The loose thickness of the concrete is 20 percent more than the compacted
or finished thickness. Tandem rollers are recommended. The rolling operation is completed
before the final setting time of cement. Curing is done as per conventional method.
Cement grouted and rolled concrete are suitable for base course only. There are two methods of
construction of cement concrete slab.
1) Alternate bay method
2) Continuous bay method
Alternate bay method of construction means constructing a bay of one slab in alternate
succession leaving the next or intermediate bay to follow up after a gap of one week or so.
But it has following drawbacks:
A. Large number of transverse joints are to be provided. This increases the construction cost
and reduces the smooth riding quality of the surface.
B. During rain, the surface water collects on the subgrade between the finished bays.
C. The construction is spread over the full width of road and the traffic will have to be
completely diverted.
In general the continuous bay method is preferred mainly because of the advantage that
constructionof half the pavement width can be taken at a time while essential traffic could be
diverted on the other half of the road.
5.4.1 SPECIFICATION OF MATERIAL FOR CEMENT CONCTETE SLAB

The materials required for plain concrete are cement coarse aggregates, fine aggregates and
water incase reinforcement is provided, steel wire fabric or bar mats may be used of the required
size and spacing. Other materials are for the construction of joints, such as load transfer devices,
joints filler and sealer.
5.4.2 CEMENT
Ordinary Portland cement is generally used in case of urgency rapid hardening cement may be
used to reduce curing time.
5.4.3 COARSE AGGREGATES
The maximum size of coarse aggregates should not exceed one fourth the slab thickness. The
gradation of coarse aggregates may range from 50 to 4.75 or 40 to 4.75 mm, the aggregate is
collected in two size ranges, one below and the other above 20 mm size, when the grading is
from 20 to 50 mm, the materials are collected in two groups, below and above 25 mm size the
aggregate should be free from harmful materials such as iron, pyrites, coal, mica, clay alkali,
organic impurities etc. the coal lignite, clay or fines passing 75 micron sieve in the coarse
aggregates should not be more than one percent by weight the desirable limits of properties are:
Aggregate crushing value: 30% maximum
Aggregate impact value: 30% maximum
Los angeles abrasion value: 30% as per ISI and
35% as per IRC
Soundness, average loss in
Weight after 10 cycles: 12% maximum in sodium sulphate
18% maximum in magnesium sulphate

5.5 CONSTRUCTION STEPS FOR FLEXIBLE PAVEMENT
5.5.1 PREPREATION OF EXISTING BASE COURSE LAYER
The existing surface is prepared by removing the pot holes or ruts if any. The irregularities are
filled in with premix chipping at least a week before laying surface course. If the existing
pavement is extremely wavy, a bituminous levelling course of adequate thickness is provided to
lay a bituminous concrete surface course on a binder course instead of directly laying it on a
WBM.
5.5.2 APPLICATION OF TACK COAT
It is desirable to lay asphalt concrete (AC) layer over a bituminous base or a bindercourse. A tack
coat of a bitumen is applied at 6 to 7.5 kg/m2 area. This quantity may be increased to 7.5 to 10 kg
for non-bituminous base.
5.5.3 PREPREATION AND PLACING OF PREMIX
The premix is prepared in hot mix plant of a required capacity with the desired quality control.
The bitumen may be heated up to 150-170C and the aggregate temperature should not differ by
over 14C from the binder temperature. The hot mixed material is collected from the mixer by
the transporters, carried to the location and is spread by a mechanical paver at a temperature of
121-163C. The camber and the thickness of layer are actually verified. The control of
temperature during the mixing and the compaction are of great significance in the strength of the
resulting pavement structure.
5.5.4 ROLLING
A mix after it is placed on the base course, is thoroughly compacted by rolling at a speed not
more than 5km/hour. The initial or breakdown rolling is done by 8 to 12 tonnesrollers and the
intermediate rolling is done with a fixed wheel pneumatic roller of 15-30 tonnes having a tyre
pressure of 7kg/cm2 the wheels of roller are kept damp with water. The number of passes
required depends on the thickness of the layer. In warm weather rolling on the next day helps to
increase density of initial rolling was not adequate. The final rolling or finishing is done by 8-12
tonnestandem roller.

5.5.5 QUALITY CONTROL OF BITUMINOUS CONCRETECONSTRUCTION
The routine checks are carried out at site to ensure the quality of resulting pavement mixture and
the pavement surface. Periodic checks are made for:
A. Aggregate grading
B. Grade of bitumen
C. Temperature grade
D. Temperature of paving mixture during mixing and compaction
At least one sample for every 100 tonnes the mix discharge by the hot mix plant is collected and
tested for above requirement.
5.5.6 FINISHED SURFACE
The AC surface should be checked by 3m straight edge. The longitudinal undulations should not
be exceeding 8mm and the number of undulations higher than 6mm should not exceed 10m in a
length of 300 metre. The cross profile should not have undulations exceeding 4.0 mm.
5.6 CONSTRUCTION STEPS FOR CEMENT CONCRETE PAVEMENT

SLAB

Fig. 5.1 Cement concrete pavement slab
5.6.1 PREPREATION OF SUBGRADE AND SUB-BASE
The preparation of sub-base for laying of the concrete slabs should comply with the following
requirement; that no soft spots are present in the subgrade or sub-base; that the uniformly
compacted subgrade or sub-base extend at least 30 cm on either side of the width to be
concreted; that the subgrade is properly drained that the minimum modulus of subgrade reaction
obtained with a plate bearing test is 5.54 kg/cm2.
The subgrade is prepared and checked atleasttwo days in advance of concreting. The subgrade is
or sub-base is kept in moist condition at the time when the cement concrete is placed. If
necessary, it should be saturated with water for 6-20 hours in advance of placing concrete. Water
proof paper may also be placed whenever the cement concrete.
5.6.2 PLACING OF FORMS
The steel or wooden forms are used for the purpose.
The steel forms are of M.S. channel sections and their depth is equal to the thickness of the
pavements. The sections have a length of at least 3m except on curves of less than 45.0 m radius,
where shorter sections are used. When set to grade, the maximum deviation of the top surface of
any section from a straight line is not exceeded by 3mm.
Wooden forms are dressed on side, these have maximum base width of 10 cm for slab thickness
of 20 cm and minimum base width of 15 cm for slabs over 20 cm thick. The forms are jointed
neatly and are set with exactness to the required grade and alignment.
5.6.3 BATCHING OF MATERIALS AND MIXING
After determining the proportion of ingredients for the field mix, the fine aggregates and coarse
aggregates are proportioned by weight in a weight batching plant and placed into the hopper
along with the necessary quantity of cement. Cement is measured by the bag. All batching of

material is done on the basis of one or more whole bags of cement, the weight of one bag of
cement is taken as 50 kg or the unit weight of cement weight is taken as 1440 kg/cm2
The mixing of concrete is done in batch mixer which will ensure a uniform distribution of the
materials throughout the mass so that the mix is uniform in colour and is homogeneous.
The batch of cement, fine aggregate and coarse aggregate is led together into the mixer. The
water for mixing is introduced into the drum within the first 15 seconds of mixing. The mixing of
each batch is commenced within one and half minute after all, materials are placed in the mixer.
5.6.4 TRANSPORTING AND PLACING OF CONCRETE
The cement concrete is mixed in quantities required for immediate use and is deposited on the
soil subgrade or sub-base to the required depth and width of the pavement section within the
formwork in the continuous operation. The spreading is done uniformly. A certain amount of
redistribution is done with shovels. Needle vibrator is employed in lieu of rodding and splicing
of the concrete.
5.6.5 COMPACTION AND FINISHING
The surface of pavement is compacted either by means of power driven finishing machine or a
vibrating hand screed for areas where the width of the slab is very small at the corner of the road
junction. Hand consolidation and finishing may be adopted.
Concrete as soon as placed is struck off uniformly and screed to the crown and cross section of
the pavement to confirm the grade.
The tamper is placed on the side forms and is drawn ahead in combination with the series of lifts
and drops to compact the concrete.
5.6.6 FLOATING AND STRAIGHT EDGING
The concrete is further compacted by means of longitudinal float. The longitudinal float is held
in a position parallel to carriageway center-line and passed gradually from one side of the
pavement to the other. After the longitudinal floating is done in the excess water gets
disappeared, the slab surface is tested for its grade and level with the straight edge.

5.6.7 BELTING, BROOMING AND EDGING
Justbefore the concrete becomes hard, the surface is belted with the two ply canvas belt. The
short strokes are applied transversely to the carriageway.
After belting the pavement is given a broom, finish with fiber broom brush. The broom is pulled
gently over the surface of the pavement transversely from edge to edge. Brooming is done
perpendicular to the center line of the pavement.
Before the concrete develops, the initial set the edges of the slab are carefully finished edging
tool.
5.6.8 CURING OF CEMENT CONCRETE
The entire pavement surface of the newly laid cement concrete is cured in accumulation with the
following methods.
A) INITIAL CURING
The surface of the pavement surface is entirely covered with cotton or jute.
B) FINAL CURING
Curing with wet soil exposed edges of the slab are banked with soil berm. A sandy soil free from
stones is placed. The soil is thoroughly kept saturated for 14 days.
5.6.9 CONSTRUCTION OF JOINTS IN CEMENT CONCRETE PAVEMENTS
Joints are provided in cement concrete for expansion, contraction and warping of the slabs due to
variation in temperature of slab.
Joints are classified depending upon their direction of placement.
Transverse joint
Transverse joint is further classified into:
A) EXPANSION JOINT

These joints are provided to allow for expansion of the slabs due to rise in slab temperature
above the construction temperature of the cement concrete. Expansion joints also permits the
contraction of slab. Expansion joint in India are provided at interval of 50-60m for smooth laid in
winter and 90-120m for interface laid in summer. However for rough interface the spacing
between expansion joints may be 140m.
Fig. 5.2 Expansion joint in rigid pavement
B) CONTRACTION JOINT
Contraction joints are provided to permit the contraction of slab. These joints are spaced closer
than expansion joints. Load transference at the joints is provide through the physical interlocking
by the aggregates projecting out at the joint faces. As per IRC specification, the maximum
spacing of contraction joint in unreinforced CC slabs is 4.5m and in reinforced slab of thickness
20cm is 14m.

Fig 5.3 Contraction joint in rigid pavement
5.7 FLEXIBLE PAVEMENT FAILURES
5.7.1 FAILURES IN SUBGRADE
One of the prime causes of flexible pavement failure is excessive undulations or waves and
corrugation in the pavement surface.
The failure of subgrade may be attributed due to two basic reason:
1. Inadequate stability
2. Excessive stress application
Inadequate stability may be due to the inherent weakness of the soil itself or excessive moisture
or improper compaction excessive stress application is due to inadequate pavement thickness or
loads in excess of design value.
5.7.2 FAILURES IN SUB-BASE OR BASE COURSE
A) INADEQUATE STABILITY OR STRENGTH
Poor mix proportioning or inadequate thicknesses are main reasons for the lack of stability or
strength or sub-base or base course. Soft varieties of stone aggregates also make the base course
layer weak.

B) LOSS OF BINDING ACTION
Due to the internal movements of aggregates in sub-base or base course layers under the repeated
stress application, the composite structure of the layers get disturbed. This results in the loosing
of the total mass.
C) LOSS OF BASE COURSE MATERIALS
The loss of base course materials is only possible when either the base course is not covered with
a wearing course or the wearing course has completely worn out. The exposed aggregates of the
base course also may from dust due to abrading action and attrition with further use of such
pavement section, there is loss of stone aggregates forming pot hole.
D) INADEQUATE WEARING COURSE
Absence of wearing course or inadequate thickness or stability or wearing course to the

damaging effects of climatic variations mainly due to rains, frost action and the traffic. Pervious
wearing course also permits the surface water to sweep through and soften the base course thus
weakening it.
5.7.3 RIGID PAVEMENT FAILURE
Failures of cement concrete pavements are recognized mainly by the formation of structural
cracking, the failure is mainly due to two factors:
1. Deficiency of pavement materials
2. Structural inadequacy of the pavement system.
Deficiency of pavement materials
Following are chief causes:
1. Soft aggregates
2. Poor, workmanship in joint construction
3. Poor join filler and sealer materials
4. Poor surface fin

5. Improper and insufficient curing
6. Structural inadequacy of pavement system
Following are chief causes:
1. Inadequate pavement thickness
2. Inadequate sub grade support and poor sub grade soil.
5.7.4 TYPICAL FLEXIBLE PAVEMENT FAILURE
A) ALLIGATOR (MAP) CRACKING
This is the most common type of failure and occurs due to fatigue. Localized weakness in the
underlined base course would also can cause a cracking of the surface course in this pattern.
B) SHEAR FAILURE CRACKING
Shear failures are associated with the inherent weakness of pavement mixtures. The shear
failures causes upheaval of pavement material by forming a fraction of cracking.
C) LONGITUDINAL CACKING
Due to frost action and differential volume changes in subgrade longitudinal cracking is
cause din pavements, traversing through the pavement, traversing through the full pavement
thickness.
D) FROST HEAVING
In the case of frost heaving there is mostly a localized heaving up of a pavement portion
depending upon the ground water and climatic conditions.
E) LACK OF BINDING WITH LOWER LAYER
Slipping occurs when the surface course is not (keyed) bound with the underlined base. Such
condition are more frequent in case when the bituminous surfacing is provided over the existing
cement concrete based course or soil.
5.7.5 TYPICAL RIGID PAVEMENT FAILURE

A) SCALING OF CEMENT CONCRETE
Scaling is observed in cement pavement showing over all deterioration of the concrete .The
scaling is mainly attributed due to the deficiency in the mix or presence of some chemical
impurities which damage the mix further due to excessive vibrations giving to the mix, and
cement mortar comes to the top during construction and makes the pavement surface rough and
shabby in appearance.
B) SHRINKAGE CRACKS
During the curing operations of cement concrete pavement immediately after construction the
shrinkage cracks normally develop.
C) WARPING CRACKS
If the joints are not designed tom accommodate s the warping of slabs of edges, this results in
development of excessive stresses due to warping and the slab developed the cracking at the
edge in irregular pattern.
D) MUD PUMPING
Mud pumping is recognized when the soil slurry ejects out through the joints and cracks of
cement concrete pavement caused during the downward movement of slab under the wheel load.
5.8 MAINTENANCE OF FLEXIBLE PAVEMENT
Mainly the maintenance work of flexible pavement consists of:
1. Patch repairs
2. Pot holes and repairs
3. Surface treatments

4. Resurfacing
5.8.1 PATCH REPAIRS
Patch repairs are carried out on the damage or improper road surface .Patching may be done or
affected localized area or sections using a cold premix.
5.8.2 POT HOLES AND REPAIRS
Pot holes are cut to square or rectangular forms and materials placed in sections are thoroughly
removed until the sound materials are encountered. The excavated holes are cleaned and applied
with primers. A premixed material is then placed in the sections .Generally, cut back or
emulsions are used as binder. The materials so placed in the pot holes, is well compacted by
ramming to avoid any reveling. The materials in the pot holes are placed in thickness or so .The
finished level of the patch are kept slightly above original level to allow for subsequent
consolidation under traffic.
5.8.3 WET MIX MACADAM
This work shall consists of laying and compacting clean crushed, graded aggregate and granular
material premix with a water, to a dense mass on a prepared sub base/sub grade or existing
pavement as the case may be in accordance with the requirement of these specifications.
Materials shall be laid in one or more layers as necessary to lines, grades and cross-section
shown on the approved drawing. The thickness of a single compacted Wet Mix Macadam layer
shall not be less not be depth of single layer of the sub-base course may be increased to 200mm
upon approval of an Engineer.
5.8.4 AGGREGATES
PHYSICAL REQUIREMENTS:
Coarse aggregate shall be crushed stone. If crushed gravel is used ,not less than 90 by weight of
the gravel pieces retained on 4.75mm sieve shall have at least two fractured faces. The aggregate
shall confirm to the physical requirement as shown in table below:-
Table. 5.1 Standard values of Testing

Test Test method Requirements
1. *Los Angles IS : 2386(Part-4) 40 Percent (Max)
Abrasion Value
Or
*Aggregate IS : 2386 (Part-4) 30 Percent (Max)

Impact Value Or IS : 5640
2. Combined Flakiness and IS : 2386 (Part-1) 30 Percent (Max)**
Elongation Indices (Total)
* Aggregate may satisfy the requirement of either of the two tests
** To determine this combined proportion, the flaky stone from a representative sample should
be separated out .Flakiness index is weight of flaky stone metal divided by weight of the stone
sample. Only the elongated particle is separated from the remaining (non-flaky) stone metal.
Elongation index is weight of elongated particle divided by total non-flaky particles. The value
of Elongation index and Flakiness index so found are added up. If water absorption value of
coarse aggregate is greater than 2%, the soundness test shall be carried out on the material
delivered to site as per IS: 2386 (Part-5).
GRADING REQUIREMENT: The aggregate should follow the following grading given
below:-
1. GRADING REQUIREMENT OF AGGREGATE FOR WET
2. MIX MACADAM
Table. 5.2 Seive analysis

IS SIEVE DESIGNATION % BY WEIGHT PASSING THE IS
SIEVE
53.00 mm 100
45.00 mm 95-100
22.40 mm 60-80
11.20 mm 40-60
4.75 mm 25-40
2.36 mm 15-30
600.00 micron 8-22
75.55 micron 0-8
Materials finer than 425 micron shall have Plasticity Index(PI) not exceeding 6.The final
gradation approved within these limits shall be graded from well graded from coarse to fine and
shall not be vary from the low limit on one sieve to the high limit on the adjacent sieve or vice-
versa.
5.8.4 CONSTRUCTION OPERATIONS
1. PREPARATION OF BASE:
The base should be prepared from different materials. Materials like small-stones, crushed
stones, etc. are used.
2. PROVISION OF LATERAL CONFINEMENT OF AGGREGATE:
While constructing wet mix macadam, arrangement shall be made for the lateral confinement of
wet mix. This shall be done by laying materials in adjoining shoulders along with that of wet mix
macadam layer.
3. PREPARATION OF MIX:
For small quantity of wet mix work, the engineer may permit the mixing to be done in concrete
mixers Wet mix macadam shall be prepared in an approved mixing plant of suitable quantity
having provision for controlled addition of water and forced/positive mixing arrangement like

pug mill and pan type mixture of concrete batching plant..While adding water, due allowance
should be done for evaporation losses. However, at the time of compaction, water in the wet mix
should not vary from the optimum value by more than agreed limit. The mixed material should
be uniformly wet and no segregation should be permitted.
4. SPREADING OF MIX:
Immediately, after mixing the aggregate shall be spread uniformly and evenly upon the prepared
sub grade/sub-base/base in required quantities. In no case should these be dumped in heaps
directly on the area where these are to be laid nor shall their hauling over a partly completed
stretch be permitted.
The mix may be spread by a paves finisher or motor grader. For portions where mechanical
means cannot be used, manual means as approved by an engineer shall be used. The motor
graded shall be capable of spreading the material uniformly all over the surface. Its blade should
have hydraulic control suitable for initial adjustments and maintaining the same as so as to
achieve the specified slope and grade.
5. COMPACTION:
After the mix has been laid to the required thickness, grade and cross fall/camber the same shall
be uniformly compacted, to the full depth with a suitable roller. If the thickness of single
compacted layer does not exceed 100mm, a smooth wheel roller of 80 to 100 kN weight may be
used. For a compacted single layer up to 200mm, the compaction shall be done with the help of
vibratory roller of minimum static weight of 80 to 100 kN or equivalent capacity roller. The
speed of roller shall not exceed 5km/h.
The portions in camber, rolling should begin at the edge with the roller running forward and
backward until the edges have been firmly compacted. The roller shall then progress gradually
towards the center parallel to the center line of the road uniformly overlapping each preceding
tracks by at least one-third width until the entire surface has been rolled.
Any displacement occurring as a result of reversing of the direction of roller or from any other
cause shall be corrected at once as specified and/or removed and made good.

Rolling should not be done when sub-grade is soft and yielding or when it causes a wave like
motion in the sub-base/base course or sub-grade. If the irregularities develop during rolling
which exceed 12mm when tested with a 3m straight edge, the surface should be loosened and
premix material added or removed as required before rolling again so as to achieve uniform
surface conforming to the desired grade and cross fall. In no case should be use of unmixed
material be permitted to make up the depressions.
Rolling shall be continued till the density achieved is at least 98 per cent of the maximum dry
density of the material.
After completion, the surface of any finished layer shall be well-closed, free from movement
under compaction equipment or any compaction planes, ridges, cracks and loose material.
5.8.5 TEST ON BITUMIN
There are number of tests to assess the properties of bituminous materials. The following tests
are usually conducted to evaluate different properties of bituminous materials.
1. Penetration test
2. Ductility test
3. Softening point test
1. PENETRATION TEST
It measures the hardness or softness of bitumen by measuring the depth in tenths of a millimeter
to which a standard loaded needle will penetrate vertically in 5seconds .BIS had standardized the
equipment and test procedure. The penetrometer consists of a needle assembly with total weight
of 100g and a device for releasing and locking any position. The bitumen is softened to a pouring
consistency, stirred thoroughly and poured into containers at a depth of at least 15mm in excess
of the expected penetration. The test should be conducted at a specified temperature of 25c.It
may be noted that penetration value is largely influenced by any inaccuracy with regards to
pouring temperature, size of needle, weight placed on the needle and the test temperature.
A grade of 40/50 bitumen means the penetration value in the range 40 to 50 at standard test
conditions. In hot climate , a lower penetration grade is preferred.

Fig. 5.4 Penetration Test Appratus
2. DUCTILITY TEST
Ductility is the property of bitumen that permits it to undergo great deformation or elongation.
Ductility is defined as the distance in cm,to which a standard sample or briquette of the material
will be elongated without breaking. Dimension of the briquette thus formed is exactly 1cm
square.The bitumen sample is heated and poured in the mould assembly placed on plate .These
sample with moulds are cooled in air and then in water bath at 27c temperature. The excess
bitumen is cut and surface is leveled using a hot knife. The sides of the mounds are removed ,the
clips are hooked on the machine and the machine is operated .The distance up to the point of
breaking of thread is the ductility value which is reported in cm. Ductility value gets affected by
factors such as pouring temperature, test temperature, rate of pulling etc. A minimum ductility
value of 75 cm has been specified by BIS.
Fig. 5.5 Ductility Test Appratus
3. SOFTENING POINT TEST

Softening point denotes the temperature at which the bitumen attains a particular degree of
softening under the specifications of test .The test is conducted by using ring and ball apparatus.
A brass ring containing test sample of bitumen is suspended in liquid like water or glycerin at a
given temperature .A steel balls placed upon the bitumen sample and the liquid medium is heated
at a rate of 5c per minute. Temperature is noted when the softened bitumen touches the metal
plate which is at a specified distance below. Generally, higher softening point indicates lower
temperature susceptibility and is preferred over in hot climate .
Fig. 5.5 Softening Test Appratus
5.9 Analysis of traffic density

Table . 5.3 Analysis of traffic density for Lane-1
FOLLOWING DATA FOR LANE-1
LANE TIME DATE TWO FOUR E-RICKSAW
WHEELER WHEELER
1 4:00PM 18/08/2015 26 20 5
1 3:00PM 19/08/2015 29 22 7
1 4:00PM 21/08/2015 26 26 5
1 4:00PM 22/08/2015 28 20 8
1 10:00AM 23/08/2015 26 24 4
Table . 5.4 Analysis of traffic density for Lane-2

FOLLOWING DATA FOR LANE-2
LANE TIME DATE TWO FOUR E-RICKSAW

WHEELER WHEELER
2 4:00PM 18/08/2015 22 29 7
2 3:00PM 19/08/2015 25 26 5
2 4:00PM 21/08/2015 24 33 5
2 4:00PM 22/08/2015 25 30 6
2 10:00AM 23/08/2015 30 25 3
5.10 (A) Material testing analysis

Table. 5.5 Arregates material testing
TYPE OF TEST RESULT RANGE
Aggregate Impact Test 8.51% 0-30%
Los Angeles Abrasion Test 19.82% 0-30%
Aggregate crushing value Test 23.83% 0-45%
Flakiness Test 4.95% 0-25%
Elongation Test 14.06% 0-30%
Bitumen penetration Test 11mm (8-15)mm
5.10 (B) Vehicle data collection

Table. 5.6 Growth rates of different vehicles
The actual statistics of growth rate of various vehicle classes between 2015-16
TYPES OF VEHICLE GROWTH RATE
CARS 10-15%
BUSES 5-10%
E-RICKSHAW 7-9%
TWO WHEELERS 16-20%

5.11 ABSTRACT OF COST
FOR FLEXIBLE
As per bill of quantity amount= 13196433.13 Rs
Contingency @ 1%=131964.33 Rs
Labour Cess @ 1%=131964.33Rs
Establishment charges @ 6.875%=907254.78 Rs
Grand Total=14367616.56 Rs
Flexible pavement cost per km per lane is= half of grand total
=7183808.28 Rs
FOR RIGID
As per bill of quantity amount= 13110102.82 Rs

Contingency @ 1%=131101.0252 Rs
Labour Cess @ 1%=131101.0282Rs
Establishment charges @ 6.875%=901339.5689 Rs
Grand Total=14273624.46 Rs per km per lane

MACHINERY LIST
LIST OF MACHINERY
1. EARTH COMPACTOR
2. MOTOR CRANE
3. SOIL COMPACTOR
4. BITUMIN DRUM
5. TANDOM ROLLER
6. MINI VIBRATORY ROLLER
7. HOT MIX DRUM TYPE PLANT
8. HOT MIX BATCH TYPE PLANT
9. MULTI AXLE HIGHWAY TIPPER
10. MOTOR GRIDDER
11. MINI SOIL COMPACTOR
12. PNEUMATIC ROLLER
13. PAVER FINISHER
14. WMM MIX PLANT

PICTURES OF MACHINERY USED DURING DESINING OF
PAVEMENTS
1. EARTH COMPACTOR
2. MOTOR CRANE
3. SOIL COMPACTOR

4. BITUMIN DRUM

5. TANDOM ROLLER
6. MINI VIBRATORY ROLLER

7. HOT MIX DRUM AND BATCH TYPE PLANT
7.MULTI AXLE HIGHWAY TIPPER
8.MOTOR GRIDDER
.9. MINI SOIL COMPACTOR

10. PNEUMATIC ROLLER
11. PAVER FINISHER
12. WMM MIX PLANT

CHAPTER 6
CONCLUSION
Better highway system provides varied benefits to the society .Improvement in highway results
in several benefits to the road users .It reduces operational cost per unit length of road. Saves
travel time and resultant benefits in terms of time costs of vehicle and the passengers .Reduces
the accident rates .Improve level of service and ease of driving .Increases comfort for passengers
.Assess to weather and up to what extent the pavement fulfills the intended requirements so that
the maintains and strengthening the jobs could be planned in time. It provides good feasibility
and serviceability to the road users.

REFERENCES
Buch, N. 2002. Field Trials of Concrete Pavement Product and Process

Technology - Precast Panel System for Full Depth Pavement Repairs, Technical
Proposal.Michigan State University, East Lansing.
---. 2003. Field Trials of Concrete Pavement Product and Process Technology -
Precast Panel System for Full Depth Pavement Repairs, Quarterly Progress
Report. Michigan State University, East Lansing.
Construction Technology Laboratories, Inc. (CTL). 2001. Whitetopping

Pavements in Colorado and Revision of the TWT Design Procedure. Innovative
Pavement Research Foundation, Falls Church, VA.
Sheehan, M. J., S. M. Tarr, and S. D. Tayabji. 2004. Instrumentation and Field

Testing of Thin Whitetopping Pavement in Colorado and Revision of the Existing
Colorado Thin Whitetopping Procedure. Report No. CDOT-DTD-R-2004-12.
Colorado Department of Transportation, Denver.
Tarr, S. M., M. J. Sheehan, and P. A. Okamoto. 1998. Guidelines for the

Thickness Design of Bonded Whitetopping Pavement in the State of Colorado.
Report No. CDOT-DTD-R-98-10. Colorado Department of Transportation,
Denver.
2002. High Performance Concrete Pavement, K-96 Reno County. 2002 Annual
Report. Kansas Department of Transportation, Topeka.
---. 2003. High Performance Concrete Pavement, K-96 Reno County. 2003
Annual Report. Kansas Department of Transportation, Topeka.
Ramakrishnan, V., and N. S. Tolmare. 1998. Evaluation of Non-Metallic Fiber

Reinforced Concrete in New Full Depth PCC Pavements. Report No. SD96-15-F.
South Dakota Department of Transportation, Pierre.

Design of Flexible Pavement

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CHAPTER 1

A flexible pavement is a structure consisting of superimposed layers of processed materials

CIVIL DEPARTMENT, GNITM 1

-To reduce vehicle operational cost per unit length of road.

-To improve level of service and ease of driving.

-To increase comfort for passengers.

-To reduce the accident rates.

CIVIL DEPARTMENT, GNITM 2

CIVIL DEPARTMENT, GNITM 3

2.1 LITERATURE REVIEW

2.2 TYPES OF PAVEMENT SURFACE

2.2.1 FLEXIBLE PAVEMENTS

CIVIL DEPARTMENT, GNITM 4

1) Soil sub grade

CIVIL DEPARTMENT, GNITM 5

2.2.2 RIGID PAVEMENTS

CIVIL DEPARTMENT, GNITM 6

2.3.1 BASED ON SEASONS OF THE YEAR

2.3.2 BASED ON TYPE OF CARRIG- WAY

2.3.3 BASED ON TYPE OF PAVEMENT

2.4 METHODS OF CLASSIFICATION OF ROAD

The roads are generally classified on the following basis:

2.4.1 TRAFFIC VOLUME:

CIVIL DEPARTMENT, GNITM 7

1) Heavy traffic load

2.4.2 LOAD TRANSPORTED:

2.4.3 LOCATION AND CLASSIFICATION:

1) National Highway (NH):

2) State Highway (SH):

3) Major District Roads (MDR):

4) Other District Roads (ODR):

CIVIL DEPARTMENT, GNITM 8

5) Village Roads (VR):

CIVIL DEPARTMENT, GNITM 9

COMPLETE METHODOLOGY OF THE PROJECT WORK

3.1 DATA COLLECTION

For completion of project we will be collecting the following data-

1) Old traffic data

3.2 DESIGN OF PAVEMENTS

Pavements design consists of two parts-

1) Mix design of the material to be used in each pavement component layer.

The factors to be considered for the design of pavements-

1) Design wheel load

3.2.1 DESIGN WHEEL LOAD

CIVIL DEPARTMENT, GNITM 10

1) Maximum wheel load

3.3 STANDARDS FOR FLEXIBLE PAVEMENT

CIVIL DEPARTMENT, GNITM 11

3.4 STANDARDS FOR RIGID PAVEMENT

3.5 COMPARISON OF STRUCTURAL DESIGN

CIVIL DEPARTMENT, GNITM 12

There are following two methods of pavement evaluations-

1) Structural evaluation of pavements

3.7 ESTIMATION AND COMPARISON OF COSTS

3.8 FUNCTIONS OF PAVEMENT COMPONENTS DESIGN FACTORS

FACTORS TO BE CONSIDERED IN DESIGN OF PAVEMENTS

Pavement design consists of two parts:

1) Mix design of materials to be used in each pavement component layer.