This is a report on summer training at public works department(PWD) Report is on the topic CONSTRUCTION OF FLEXIBLE PAVEMENTS.

1. RAJ KUMAR GOEL INSTITUTE OF
Technology
GHAZIABAD U.P. – 201003
CIVIL ENGINEERING
SESSION:2018-2019
INDUSTRIAL TRAINING (NCE-752)
REPORT ON SUMMER TRAINING AT PWD
RAEBARELI
SUBMITTED BY: SUBMITTED TO:
RATNESH KUSHWAHA DEPT. OF CIVIL ENGG.

2. ACKNOWLEDGEMENT
I express my satisfaction on the completion of this summer training program
and project report submission as a part of the curriculum for the degree of
Bachelor of Technology, Civil Engineering. I express my deepest gratitude to
my supervisor and mentor Mr. VIVEK MAURYA for his kind guidance
during the entire period of training. His consistent support and advices has
helped me to complete this research project successfully. Also I thank all the
members of C.D.-2 PUBLIC WORKS DEPARTMENT RAEBARELI (U.P.)
their kind support. They have always been a source of inspiration to me.
DATE: 05/07/2018 RATNESH KUSHWAHA

3. S. NO. CONTENT PAGE NO.
1 PUBLIC WORKS DEPARTMENT: AN OVERVIEW 5
2 INTRODUCTION 5
3 WHAT IS ROAD OR PAVEMENT? 6
4 TYPES OF PAVEMENTS 7
5 MATERIALS FOR PAVEMENT LAYERS 8-10
5.1 SOIL 8
5.2 AGGREGATES 9
5.3 BITUMINOUS BINDER 10
6
CONSTRUCTION OF FLEXIBLE PAVEMENT
LAYERS 12-18
6.1 SUBGRADE 11
6.2 SUB-BASE COURSE 12-13
6.3 BASE COURSE 14
SURFACE COURSE
15-166.4

4. PUBLIC WORKS DEPARTMENT: AN OVERVIEW
Public Works Department (PWD), under the Ministry of Public Works department, is the
pioneer in construction arena of Uttar Pradesh. Over about four centuries, PWD could
successfully set the trend and standard in the state`s infrastructure development. It plays a
pivotal role in the implementation of government construction projects. It also undertakes
projects for autonomous bodies as deposit works. Public works Department has highly
qualified and experienced professionals forming a multi-disciplinary team of civil, electrical and
mechanical engineers who work alongside architects from the Department of Architecture.
With its strong base of standards and professionalism developed over the years, PWD is the
repository of expertise and hence the first choices among discerning clients for any type of
construction project in Uttar Pradesh. Besides being the construction agency of the
Government, it performs regulatory function in setting the pace and managing projects for the
country's construction industry under the close supervision of the Ministry of Housing and
Public Works.
The Public works Department has highly qualified and experienced professionals forming a
multi-disciplinary team of civil, electrical and mechanical engineers who work alongside
architects from the Department of Architecture. As a sister organization falling under the
administrative control of the Ministry of Public Works department, the latter works well with
the PWD in providing service to the nation. With its strong base of standards and
professionalism developed over the years, the PWD is the repository of expertise and hence
the first choices among discerning clients for any type of construction project in our country. It
is recognized as a leader and pacesetter in the construction industry because of its consistently
superior performance.
INTRODUCTION
Development of a country depends on the connectivity of various places with adequate road
network. Roads are the major channel of transportation for carrying goods and passengers.
They play a significant role in improving the socio-economic standards of a region. Roads
constitute the most important mode of communication in areas where railways have not
developed much and form the basic infra-structure for the development and economic growth
of the country. The benefits from the investment in road sector are indirect, long-term and not
immediately visible. Roads are important assets for any nation. However, merely creating these
assets is not enough, it has to be planned carefully and a pavement which is not designed
properly deteriorates fast. India is a large country having huge resource of materials. If these
local materials are used properly, the cost of construction can be reduced. There are various
type of pavements which differ in their suitability in different environments. Each type of
pavement has its own merits and demerits. Despite a large number of seminars and
conference, still in India, 98% roads are having flexible pavements. A lot of research has been
made on use of Waste materials but the role of these materials is still limited. So there is need
to take a holistic approach and mark the areas where these are most suitable.

5. India has one of the largest road networks in the world (over 3 million km at present).For the
purpose of management and administration, roads in India are divided into the following five
category
 National Highways (NH)
 State Highways (SH)
 Major District Roads (MDR)
 Ordinary District Roads (ODR)
 Village Roads (VR)
The National Highways are intended to facilitate medium and long distance inter-city
passenger and freight traffic across the country. The State Highways are supposed to carry the
traffic along major centres within the State. Other District Roads and Village Roads provide
villages accessibility to meet their social needs as also the means to transport agriculture
produce from village to nearby markets. Major District Roads provide the secondary function
of linkage between main roads and rural roads.
Point of view geographic and population of the state is the nation's largest state. State
Industrial, economic and social development of the state and the population of each village is
absolutely necessary to re-connect to the main roads. In addition to state important national
roads, state roads and district roads and their proper broad be made to improve the quality of
traffic point of view is of particular importance. Public Works Department to build roads and
improve connectivity in rural zones, Other District Road and State broad and improvement of
rural roads and main routes narrow construction of zones and depleted bridges and brides
reconstruction of the bases are transacted on a priority basis. Also under Pradhanmantri Gram
Sadak Yojana and pre-fabricated construction of rural roads linking the work of other district
roads broad Kilometres the scale bases are edited.
Successful operation of various schemes for the Public Works Department engineers and
supervisory boards in different districts of the engineer’s office has been settled. Activities by
planning, execution, and quality control etc. remove impediments find joy in relation to the
supervision over the activities are focused. Various schemes operated by the Department of
the Office of the Regional Chief Engineers and Chief Engineers office.
WHAT IS ROAD OR PAVEMENT?
Pavement or Road is an open, generally public way for the passage of vehicles, people, and
animals.
Pavement is finished with a hard smooth surface. It helped make them durable and able to
withstand traffic and the environment. They have a life span of between 20 – 30 years.
Road pavements deteriorate over time due to-
 Impact of traffic, particularly heavy vehicles.
 Environmental factors such as weather, pollution.

6. TYPES OF PAVEMENTS
There are various types of pavements depending upon the materials used; a briefs
description of all types is given here-
FLEXIBLE PAVEMENTS
Bitumen has been widely used in the construction of flexible pavements for a long time. This
is the most convenient and simple type of construction. The cost of construction of single
lane bituminous pavement varies from 20 to 30 lakhs per km in plain areas. In some
applications, however, the performance of conventional bitumen may not be considered
satisfactory because of the following reasons-
 In summer season, due to high temperature, bitumen becomes soft resulting in
bleeding, rutting and segregation finally leading to failure of pavement.
 In winter season, due to low temperature, the bitumen becomes brittle resulting in
cracking and unevenness which makes the pavement unsuitable for use.
 In rainy season, water enters the pavement resulting into pot holes and sometimes
total removal of bituminous layer.
 In hilly areas, due to sub-zero temperature, the freeze thaw and heave cycle takes
place. Due to freezing and melting of ice in bituminous voids, volume expansion and
contraction occur. This leads to pavements failure.
 The cost of bitumen has been rising continuously. In near future, there will be scarcity
of bitumen and it will be impossible to procure bitumen at very high costs.
RIGID PAVEMENTS
Rigid pavements, though costly in initial investment, are cheap in long run because of low
maintenance costs. There are various merits in the use of Rigid pavements (Concrete
pavements) are summarized below:
 Bitumen is derived from petroleum crude, which is in short supply globally and the
price of which has been rising steeply. India imports nearly 70% of the petroleum
crude. The demand for bitumen in the coming years is likely to grow steeply, far
outstripping the availability. Hence it will be in India's interest to explore alternative
binders. Cement is available in sufficient quantity in India, and its availability in the
future is also assured. Thus cement concrete roads should be the obvious choice in
future road programmes.
 Besides the easy available of cement, concrete roads have a long life and are
practically maintenance-free.
 Another major advantage of concrete roads is the savings in fuel by commercial
vehicles to an extent of 14-20%. The fuel savings themselves can support a large
programme of concreting.

7.  Cement concrete roads save a substantial quantity of stone aggregates and this factor
must be considered when a choice pavements is made,
 Concrete roads can withstand extreme weather conditions – wide ranging
temperatures, heavy rainfall and water logging.
 Though cement concrete roads may cost slightly more than a flexible pavement
initially, they are economical when whole-life-costing is considered.
 Reduction in the cost of concrete pavements can be brought about by developing
semi-self-compacting concrete techniques and the use of closely spaced thin joints.
R&D efforts should be initiated in this area.


Materials for flexible pavement layer
The flexible pavement layer is constructed with use of following basic materials:-
 Soil
 Stone aggregates
 Bituminous Binder
 Water
SOIL
The soil is used in embankment construction should not undergo excessive settlement due
to weather changes and superimposed loads; differential settlements of the embankment
may lead to failure of pavement and other structures.
Selected superior quality soil is borrowed and used for the construction of subgrade of
pavements. Well compacted soils and stabilized soils are at times used in the sub-base or
base course of pavements of low volume roads. The soil is therefore considered as one of
the principal highway materials.
DESIRABLE PROPERTIES
 Stability
 Incompressibility
 Permanency of strength
 Minimum changes in volume and strength under adverse conditions of weather.
 Good drainage
 Ease of compaction
STONE AGGREGATES
Aggregates are inert granular materials such as sand, gravel, or crushed stone that, along
with water and Portland cement, are an essential ingredient in concrete. For a good
concrete mix, aggregates need to be clean, hard, strong particles free of absorbed chemicals

8. or coatings of clay and other fine materials that could cause the deterioration of concrete.
Aggregates, which account for 60 to 75 percent of the total volume of concrete, are divided
into two distinct categories-fine and coarse. Fine aggregates generally consist of natural
sand or crushed stone with most particles passing through a 3/8-inch (9.5-mm) sieve.
Coarse aggregates are any particles greater than 0.19 inch (4.75 mm), but generally range
between 3/8 and 1.5 inches (9.5 mm to 37.5 mm) in diameter. Gravels constitute the
majority of coarse aggregate used in concrete with crushed stone making up most of the
remainder.
Once processed, the aggregates are handled and stored in a way that minimizes segregation
and degradation and prevents contamination. Aggregates strongly influence concrete's
freshly mixed and hardened properties, mixture proportions, and economy. Consequently,
selection of aggregates is an important process. Although some variation in aggregate
properties is expected, characteristics that are considered when selecting aggregate include:
 Grading
 Durability
 Particle shape and surface texture
 Abrasion and skid resistance
 Unit weights and voids

 Absorption and surface moisture
BITUMINOUS BINDER
Bituminous materials or asphalts are extensively used for roadway construction, primarily
because of their excellent binding characteristics and water proofing properties and
relatively low cost. Bituminous materials consists of bitumen which is a black or dark
coloured solid or viscous cementitious substances consists chiefly high molecular weight
hydrocarbons derived from fractional distillation of petroleum. It has adhesive properties,
and is soluble in carbon disulphide.
Bituminous materials are very commonly used in highway construction because of their
binding and water proofing properties. The different types of bituminous binders used in
flexible pavement construction are-
 Paving grade bitumen
 Modified bituminous binders
 Cut-back bitumen
 Bitumen emulsion
Of the above bituminous binders the paving grade bitumen and modified bituminous
binders need heating before used in paving applications. Cut-back bitumen may or may not

9. need slight heating depending on the selected grade of the binder and site temperature
during mixing. When bitumen emulsion used in pavement construction heating is required.
The different grades of bitumen currently adopted in India based upon the viscosity values
and respective penetration values at 25 degree Celsius are VG10, VG20, VG30, VG40.
PROCEDURE TO CONSTRUCT PAVEMENTS
During construction of a cement concrete pavement, various steps are taken as below-
 Survey of proposed work is done by experienced engineers or by any expert of
survey, site survey includes geographical details, soil properties and site
investigation.
 After survey , a team of experienced engineers and architecture prepare detailed
plan of work with the help of various software's.
 After that a engineer prepares detailed estimate of proposed work and also prepares
a estimate regarding equipments required and labour requirements.
 Now excavation is done with the help of automatic machines and then a equipment
is used to cut nearby trees and root removal process.
 After these construction of soil sub grade , base coarse and then construction of
surface course is done.




10. SUB-GRADE
Sub-grade is a layer of natural soil or filled soil, ready to receive the pavement material over it. Traffic load
moving on the surface of the road is ultimately transferred to the sub-grade through intermediate layer of
sub-base,baseandsurfacelayer.Forthesuccessfullconstructionoftheroad,itisnecessarythatthesoilsub-
grade shouldneverbe overstressed.Stressintensityonthe sub-grade should not beofthemagnitudethat
may cause excessive deformation in the sub-grade. It is this reason that the strength properties of the soil
sub-gradeshouldbeevaluated.Thepavementdesignassumessub-gradestrengthasthebasisfordesigning
the pavement. If strength properties of the sub-grade are inferior to the expected ones, it is given suitable
treatment to impart improvement in its performance. There are a number of tests which can be used to
measurestrengthpropertiesofthesoilsub-grade.Allthesetestsare usefulintheircorrelationinthedesign.
Followingaresomeofthestandardtests,usedtoevaluatethestrengthpropertiesofthesoil-
 CBRtest
 Platebearingtest
PREPARATIONOFSUBGRADELAYER
Prepare the sub-grade layer,it isdone after placing the drainage system,piping and electric cable.The sub-
gradesurfacewillbecompactedandlevelledandbecuttomakecamberasinplan.Ifthematerialofthesoil
didnothave agoodquality,it willbe changedwithsuitable material.Baseformation coverswith50-75mm
sand layer or quarry dust and will be compacted with 8-10 tone compactors. This job must be done to
preventtheclayfromabsorbingintothestonelayerofsub-base.
GRANULARSUB-BASE(GSB)
Agranularsubbaseislaidinbetweenthesubgradeandthebasecourseofallhighwaypavements.
Subbases serve a variety of purposes, including reducing the stress applied to the subgrade
and providing drainage for the pavement structure. The granular subbase acts as a load-
bearing layer, and strengthens the pavement structure directly below the pavement
surface, providing drainage for the pavement structure on the lowest layer of the pavement
system. However, it is critical to note that the subbase layer will not compensate for a weak

11. subgrade. Subgrades with a CBR of at least 10 should provide adequate support for the
subbase.
PREPARATION OF GRANULAR SUB BASE
As the granular subbase provides both bearing strength and drainage for the pavement
structure, proper size, grading, shape, and durability are important attributes to the overall
performance of the pavement structure. Granular subbase aggregates consist of durable
particles of crushed stone or gravel capable of withstanding the effects of handling,
spreading, and compacting without generation of deleterious fines. Granular subbases are
typically constructed by spreading the materials in thin layers compacting each layer by
rolling over it with heavy compaction equipment to achieve a density greater or equal to
70% relative density. Typically, the thickness of the subbase is 6 inches with a minimum of 4
inches. Additional thickness beyond 6 inches could allow consolidation of the subbase over
time as traffic loads accumulate. Pavement problems may result from this consolidation.
BASE COURSE
The base course is the region of the pavement section that is located directly under the
surface course. If there is a subbase course, the base course is constructed directly about
this layer. Otherwise, it is built directly on top of the subgrade. Typical base course thickness
ranges from 4 to 6 inches and is governed by underlying layer properties.
Heavy loads are continuously applied to pavement surfaces, and the base layer absorbs the
majority of these stresses. Generally, the base course is constructed with an untreated crushed
aggregate such as crushed stone, slag, or gravel. The base course material will have stability
under the construction traffic and good drainage characteristics.
The base course materials are often treated with cement, bitumen, calcium chloride, sodium
chloride, fly ash, or lime. These treatments provide improved support for heavy loads, frost
susceptibility, and serves as a moisture barrier between the base and surface layers The base
course must have sufficient quality and thickness to prevent failure in the subgrade and/or
subbase, withstand the stresses produced in the base itself, resist vertical pressures that tend
to produce consolidation and result in distortion of the surface course, and resist volume
changes caused by fluctuations in its moisture content.

12. The materials composing the base course are select hard and durable aggregates, which
generally fall into two main classes: stabilized and granular. The stabilized bases normally
consist of crushed or uncrushed aggregate bound with a stabilizer, such as Portland cement or
bitumen.The quality of the base course is a function of its composition, physical properties,
and compaction of the material.
PRIME COAT:-
A prime coat is an application of a low viscosity asphalt to a granular base in preparation for
an initial layer (or surface course layer) of asphalt. The purpose of the prime coat is; to coat
and bond loose material particles on the surface of the base, to harden or toughen the base
surface to provide a work platform for construction equipment, to plug capillary voids in the
base course surface to prevent migration of moisture, and to provide adhesion between the
base course and succeeding asphalt course. After applying the prime coat, it must cure for a
minimum of 48-72 hours before asphalt is placed, with no rain in the forecast.
There are four primary purposes for the application of a prime coat on an aggregate base
course;

13. 1-Coat and bond loose material particles on the surface of the base.
2-Harden or toughen the base surface to provide a work platform for construction
equipment.
3-Plug capillary voids in the base course surface to prevent migration of moisture.
4-Provide adhesion between the base course and succeeding asphalt course.
BINDER COURSE-
The bituminous surface, or wearing course, is made up of a mixture of various selected
aggregates bound together with asphalt cement or other bituminous binders.
This surface prevents the penetration of surface water to the base course; provides a
smooth, well-bonded surface free from loose particles, which might endanger aircraft or
people; resists the stresses caused by aircraft loads; and supplies a skid-resistant surface
without causing undue wear on tires.
TACK COAT:-
The pavement surface receiving the tack coat should be clean and dry to promote maximum
bonding. Emulsified tack coat materials may be applied to cool and/or damp pavement,
however, the length of time needed for the set to occur may increase (Flexible Pavements
of Ohio, 2001). Since existing and milled pavements can be quite dirty and dusty, their
surfaces should be cleaned off by sweeping or washing before any tack coat is placed,
otherwise the tack coat material may bond to the dirt and dust rather than the adjacent
pavement layers. This can result in excessive tracking of the tack coat material.

14. Tack coat application should result in a thin, uniform coating of tack coat material covering
approximately 90 percent of the pavement surface (Flexible Pavements of Ohio, 2001). To
achieve this result, application rate will vary based on the condition of the pavement
receiving the tack coat. Too little tack coat can result in inadequate bonding between layers.
Too much tack coat can create a lubricated slippage plane between layers, or can cause the
tack coat material to be drawn into an overlay, negatively affecting mix properties and even
creating a potential for bleeding in thin overlays.
SURFACE COURSE:-
The wearing course is the upper layer in roadway, airfield, and dockyard construction. The
term 'surface course' is sometimes used, however this term is slightly different as it can be
used to describe very thin surface layers such as chip seal. In rigid pavements the upper
layer is a portland cement concrete slab. In flexible pavement, the upper layer consists
of asphalt concrete with a bituminous binder. The wearing course is typically placed on the
binder course which is then laid on the base course, which is normally placed on
the subbase, which rests on the subgrade. There are various different types of flexible
pavement wearing course, suitable for different situations. Stone mastic asphalt is a type of
flexible pavement wearing course which is typically used for heavily trafficked roads.
The functions and requirements of this layer are:
 It provides characteristics such as friction, smoothness, drainage, etc. Also it will
prevent the entrance of excessive quantities of surface water into the underlying
base, sub-base and sub-grade,
 It must be tough to resist the distortion under traffic and provide a smooth and skid-
resistant riding surface,
 It must be water proof to protect the entire base and sub-grade from the weakening
effect of water.

15. SEAL COAT:-
Sealcoat or pavement sealer is a coating for asphalt-based pavements. Seal coating is
marketed as a protective coating that extends the life of asphalt pavements. There is not
any independent research that proves these claims. Seal coating may also reduce the
friction or anti-skid properties associated with the exposed aggregates in asphalt. There are
primarily three types of pavement sealers. They are commonly known as refined tar-based
(coal tar based), asphalt-based, and petroleum-based. All three have their advantages but
are typically chosen by the contractors’ preference unless otherwise specified.
Prior to application the surface must be completely clean and dry using sweeping methods
and/or blowers. If the surface is not clean and dry, then poor adhesion will result. Pavement
sealers are applied with either pressurized spray equipment, or self-propelled squeegee
machines or by hand with a squeegee. Equipment must have continuous agitation to
maintain consistency of the sealcoat mix. The process is typically a two-coat application
which requires 24 to 48 hours of curing before vehicles can be allowed back on the surface.
Once the surface is properly prepared, then properly mixed sealer will be applied at about
60 square feet per gallon per coat.
OPENING OF TRAFFIC:-
The curing period for bituminous surface course is less and hence the surface can be opened
to traffic within 24 hours