SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez nos Conditions d’utilisation et notre Politique de confidentialité.
SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez notre Politique de confidentialité et nos Conditions d’utilisation pour en savoir plus.
Summer Training Report
CONSTRUCTION OF CEMENT CONCRETE PAVEMENT
UTTAR PRADESH PUBLIC WORKS DEPARTMENT
CONSTRUCTION DIVISION-1, CHITRAKOOT
Submitted for Partial fulfilment of
Bachelor of Technology
SUBMITTED TO- SUBMITTED BY-DEPARTMENT
OF CIVIL ENGINEERING RAVI GUPTA
GLA UNIVERSITY, MATHURA B. TECH ,4TH YEAR
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. SHIV KUMAR SINGH SIR and MR. ARWIND
KR. NAMDEV SIR 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 PUBLIC WORKS
DEPARTMENT, CONSTRUCTION DIVISION-1, CHITRAKOOT, U.P. for
their kind support. They have always been a source of inspiration to me.
DATE: - 30/08/2014 RAVI GUPTA
TABLE OF CONTENTS
S. NO. CONTENT PAGE NO.
1 PUBLIC WORKS DEPARTMENT: AN OVERVIEW 4
2 INTRODUCTION 4
3 WHAT IS ROAD OR PAVEMENT? 6
4 TYPES OF PAVEMENTS 6
5 TYPES OF CONCRETE PAVEMENT 7
6 MINERALS USED 8
7 CEMENT 9
8 SAND 10
9 AGGREGATE 10
10 PROPORTIONING 12
11 PROCEDURE TO CONSTRUCT PAVEMENT 12
12 PREPARATION OF THE SUB- GRADE OR BASE
13 MIXING AND TRANSPORTATION OF
14 PLACING OF CONCRETE 14
15 SLIPFORM CONCRETE PAVING 15
16 EXECUTION OF JOINTS 17
17 CURING 19
18 PROTECTION OF THE CONCRETE PAVEMENT 19
19 SPECIAL MEASURES 20
20 OPENING TO TRAFFIC 21
21 COST ANALYSIS OF RIGID PAVEMENT 21
22 CONCLUSION 26
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 Bangladesh.
It is recognized as a leader and pacesetter in the construction industry because of its
consistently superior performance.
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.
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
National Highways (NH)
State Highways (SH)
Major District Roads (MDR)
Other 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
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-
The impact of traffic, particularly heavy vehicles.
Environmental factors such as weather, pollution.
Many people rely on paved roads to move themselves and their products rapidly and reliably.
One of the primary functions is load distribution. It can be characterized by the tire loads,
tire configurations, repetition of loads, and distribution of traffic across the pavement, and
Pavement material and geometric design can affect quick and efficient drainage. These
eliminating moisture problems such as mud and pounding (puddles). Drainage system
Surface drainage: Removing all water present on the pavement surface, sloping, chambers,
Subsurface drainage: Removing water that seep into or is contained in the underlying sub-grade.
TYPES OF PAVEMENTS
There are various types of pavements depending upon the materials used; a briefs description
of all types is given here-
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, ravelling 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, 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
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.
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.
TYPES OF CONCRETE PAVEMENTS
1. PLAIN CONCRETE OR SHORT PAVEMENT SLABS
This type of pavement consists of successive slabs whose length is limited to about 25 times
the slab thickness. At present it is recommended that the paving slabs not be made longer
than 5,even if the joints have dowels to transfer the loads. The movements as a result of
fluctuations in temperature and humidity are concentrated in the joints. Normally, these joints
are sealed to prevent water from penetrating the road structure. The width of the pavement
slabs is limited to a maximum of 4.5 m.
2. REINFORCED CONCRETE
Continuously reinforced concrete
Continuously reinforced concrete pavements are characterised by the absence of transverse
joints and are equipped with longitudinal steel reinforcement. The diameter of the reinforcing
bars is calculated in such a way that cracking can be controlled and that the cracks are
uniformly distributed (spacing at 1 to 3 m). The crack width has to remain very small, i.e. less
than 0.3 mm.
Reinforced pavement slabs
Reinforced concrete pavement slabs are almost never used, except for inside or outside
industrial floors that are subjected to large loads or if the number of contraction joints has to
Steel fibre concrete
The use of steel fibre concrete pavements is mainly limited to industrial floors. However, in
that sector they are used intensively. For road pavements steel fibre concrete can be used for
thin or very thin paving slabs or for very specific application.
Concrete is widely used in domestic, commercial, recreational, rural and educational
Communities around the world rely on concrete as a safe, strong and simple building
material. It is used in all types of construction; from domestic work to multi-storey office
blocks and shopping complexes.
Despite the common usage of concrete, few people are aware of the considerations involved
in designing strong, durable, high quality concrete.
There are mainly three materials used primarily-
Cement is a binder, a substance that sets and hardens independently, and can bind other
materials together. The word "cement" traces to the Romans, who used the
term caementicium to describe masonry resembling modern concrete that was made from
crushed rock with burnt lime as binder. The volcanic ash and pulverized brick additives that
were added to the burnt lime to obtain a hydraulic binder were later referred to as cementum,
cimentum, cement, and cement.
Cements used in construction can be characterized as being either hydraulic or non-hydraulic.
Hydraulic cements (e.g., Portland cement) harden because of hydration, a
chemical reaction between the anhydrous cement powder and water. Thus, they can harden
underwater or when constantly exposed to wet weather. The chemical reaction results in
hydrates that are not very water-soluble and so are quite durable in water. Non-hydraulic
cements do not harden underwater; for example, slaked limes harden by reaction with
atmospheric carbon dioxide.
The most important uses of cement are as an ingredient in the production of mortar in
masonry, and of concrete, a combination of cement and an aggregate to form a strong
TYPES OF CEMENT:-
Portland cement is by far the most common type of cement in general use around the world.
This cement is made by heating limestone (calcium carbonate) with small quantities of other
materials (such as clay) to 1450 °C in a kiln, in a process known as calcinations, whereby a
molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, or
quicklime, which is then blended with the other materials that have been included in the mix.
The resulting hard substance, called 'clinker', is then ground with a small amount
of gypsum into a powder to make 'Ordinary Portland Cement', the most commonly used type
of cement (often referred to as OPC). Portland cement is a basic ingredient
of concrete, mortar and most non-specialty grout. The most common use for Portland cement
is in the production of concrete. Concrete is a composite material consisting
of aggregate (gravel and sand), cement, and water. As a construction material, concrete can
be cast in almost any shape desired, and once hardened, can become a structural (load
bearing) element. Portland cement may be grey or white.
Portland fly ash cement
It contains up to 35% flyash. The fly ash is pozzolanic, so that ultimate strength is
maintained. Because fly ash addition allows lower concrete water content, early strength can
also be maintained. Where good quality cheap fly ash is available, this can be an economic
alternative to ordinary Portland cement.
Portland pozzolana cement
Its includes fly ash cement, since fly ash is a pozzolana , but also includes cements made
from other natural or artificial pozzolans. In countries where volcanic ashes are available.
Portland silica fume cement
Addition of silica fume can yield exceptionally high strengths, and cements containing 5–
20% silica fume are occasionally produced. However, silica fume is more usually added to
Portland cement at the concrete mixer
Sand is a naturally occurring granular material composed of finely divided rock and mineral
particles. The composition of sand is highly variable, depending on the local rock sources and
conditions, but the most common constituent of sand in inland continental settings and non-tropical
coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz.
The second most common type of sand is calcium carbonate, for example aragonite, which
has mostly been created, over the past half billion years, by various forms of life,
like coral and shellfish. It is, for example, the primary form of sand apparent in areas where
reefs have dominated the ecosystem for millions of years like the Caribbean.
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 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.
Natural gravel and sand are usually dug or dredged from a pit, river, lake, or seabed. Crushed
aggregate is produced by crushing quarry rock, boulders, cobbles, or large-size
gravel. Recycled concrete is a viable source of aggregate and has been satisfactorily used in
granular sub bases, soil-cement, and in new concrete. Aggregate processing consists of
crushing, screening, and washing the aggregate to obtain proper cleanliness and gradation. If
necessary, a benefaction process such as jigging or heavy media separation can be used to
upgrade the quality.
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:
particle shape and surface texture
abrasion and skid resistance
unit weights and voids
absorption and surface moisture
Grading refers to the determination of the particle-size distribution for aggregate. Grading
limits and maximum aggregate size are specified because grading and size affect the amount
of aggregate used as well as cement and water requirements, workability.
Fine aggregate shall consist of sand, or sand stone with similar characteristics, or
combination thereof. It shall meet requirements of the State Department of Transportation of
Uttar Pradesh , Section 501.3.6.3 of the Standard Specifications for Highway and Structure
Construction, current edition.
Coarse aggregate shall consist of clean, hard, durable gravel, crushed gravel, crushed
boulders, or crushed stone. It shall meet the requirements of the State Department of
Transportation of Uttar Pradesh , Section 501.3.6.4 of the Standard Specifications for
Highway and Structure Construction, current edition.
The following table sets forth the master limits of the job mix for the several grades of
concrete, and designates the quantities of materials and relative proportions for each grade of
concrete. For Air-Entrained High-Early-Strength Concrete, as required or permitted when
High-Early-Strength Cement is used, the proportions shall be as given in the table.
The quantities of aggregates set forth in the tabulations are for oven dry materials having a
bulk specific gravity of 2.65. For aggregates having a different specific gravity, the weights
shall be adjusted in the ratio that the specific gravity of the material used bears to 2.65 .
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 soft ware's.
after that a engineer prepares detailed estimate of proposed work and also prepares a
estimate regarding equipments required and labours 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.
and after these construction of soil sub grade , base coarse and then construction of
concrete slab is done.
PREPARATION OF THE SUB- GRADE OR BASE
The road sub grade has to be prepared carefully, in order to realize everywhere a pavement
structure of an adequate and uniform thickness. This allows to provide a homogeneous bond
between the concrete slab and its foundation which is important for the later behaviour of the
For roads with a base, drainage of the water must be provided. Mud, leaves, etc. have to be
When the base is permeable, it should be sprayed with water in order to prevent the mixing
water from being sucked out of the concrete.
However, if the base is impermeable (e.g. if the concrete is placed on a watertight asphalt
concrete interlayer) it can be necessary under warm weather conditions to cool down this
layer by spraying water on the surface.
The following points are important for roads without a foundation:
Drainage of all surface water;
Good compaction of the sub grade;
Filling and compaction of any ruts caused by construction traffic;
It is forbidden to level the sub grade by means of a course of sand. If the sub grade
has to be levelled, it is advisable to do this by using a granular material: either slag or
coarse aggregate e.g. with a grain size 0/20;
Provide an additional width of the sub grade for more lateral support.
It must always be avoided that water is sucked from the cement paste into the substructure or
the base. This can be accomplished by either moderately moistening the sub grade, or by
applying a plastic sheet on the substructure of the pavement. The latter work must be done
with care, to prevent the sheet from tearing or being pulled loose by the wind.
MIXING AND TRANSPORT OF CONCRETE
CONCRETE MIXING PLANT
The concrete mixing plant must have a sufficient capacity in order to be able to continuously
supply concrete to the paving machines. The mix constituents and admixtures have to be
dosed very accurately. The number of aggregate feed bins has to equal at least the number of
different aggregate fractions. The bins shall have raised edges to prevent contamination of the
aggregate fractions. The equipment for loading the materials shall be in good condition and
shall have sufficient capacity to be able to continuously feed the bins. The bucket of the
loaders shall not be wider than the bins. The content of the cement silos and the water tank
are in proportion to the production rates.
For small works, permanent concrete mixing plants are often called on. In that case, mixing
plants that are inspected and that can deliver Indian quality certification concrete should be
Furthermore it is useful and even essential to have a communication system between the
concrete mixing plant and the construction site in order to coordinate the batching and paving
TRANSPORT OF THE CONCRETE
Sufficient trucks must be available to continuously supply the paving machines. The number
depends on the yield at the construction site, the loading capacity of the trucks and the cycle
time (i.e. the transport time plus the time required to load and unload a truck). The loading
capacity and the type of truck to be used depend on the nature of the work, the haul roads and
the concrete paving machines.
Usually, the specifications prescribe that the concrete has to be transported in dump trucks as
paving concrete consists of a relatively dry mix having a consistency that makes transport and
unloading in truck mixers difficult. Furthermore, dump trucks can discharge the concrete
faster. For small works and in urban areas, the use of truck mixers is increasingly accepted.
Under these circumstances an admixture (e.g. a superplastisizer ) can be mixed in just before
discharging the concrete.
The necessary measures have to be taken to prevent changes of the water content and
temperature of the concrete during transport. To this end, the specifications prescribe to cover
the dump trucks by means of a tarpaulin.
PLACING THE CONCRETE
Usually the concrete is placed using slip form paving machines which applies for all
categories of roads. This equipment meets both the requirements for quality and for the
envisaged rate of production. Conventional concreting trains riding on set up rails, are hardly
used any more for roadwork's in our country. For this reason this manner of execution will
not be dealt with here. However, the technique of manually placing the concrete using forms
is still applied in certain cases, such as for the construction of roundabouts with a small
diameter, at intersections, for repair work or when the execution conditions are such that slip
form pavers cannot be utilized. This occurs increasingly often in urban areas for the
construction of pavement surfaces of exposed aggregate and possibly coloured concrete.
SLIP FORM CONCRETE PAVING
PREPARATION OF THE TRACK RUNWAY
The quality of the runway for the tracks of the paving equipment  is undoubtedly one of
the most important factors that contribute to the realisation of a smooth pavement surface. In
connection therewith, the following criteria have to be met:
sufficient bearing capacity, so that the slip form paver can proceed without causing
good skid resistance to prevent the tracks from slipping, especially when paving on a
good evenness to avoid that the self-levelling systems have to compensate for
excessive differences in height. The track runway is a determining factor for the
steering and consequently its surface has to at least as smooth as the concrete paving
surface itself. The runway surface has to be permanently cleaned prior to the passage
of the tracks.
The track runway has to be wide enough taking into account:
the greatest width of the paving machine plus an extra width (especially on
the necessary space for placing the sensor lines.
The supply of the concrete has to be arranged in such a way that a continuous placement can
be guaranteed without detrimental interruptions as each standstill can cause unevenness's.
This implies a sufficient capacity of the concrete mixing plant and of the means of
transportation of the concrete.
The concrete is discharged:
either directly in front of the machine, using dump trucks. The concrete must be
discharged gradually, in order to limit the drop height. A crane is often necessary,
especially for larger working widths, in order to adequately spread the concrete mix;
or in the bin of a side feeder, for example if transport by dump trucks on the
foundation is impossible because of the presence of dowel chairs or reinforcement
or in a supply container, from which the concrete is scooped with a crane.
It cannot be overemphasised that properly spreading the concrete in front of the slip form
paving machine is very important for the final quality of the work, especially with regard to
the smoothness. It is of great importance that in front of the slip form paver, a constant and
sufficient amount of concrete is available at all times so that a continuous paving process can
be guaranteed. The paver should never be used to push the concrete forward.
For large casting widths the concrete is preferably spread either by means of a placer/spreader
machine that operates in front of the paver or, by the slip form paver itself (side feeder,
spreading augers, wagon,…). The use of a placer/spreader, allows the slip form paver to
proceed more steadily. The distance between the placer/spreader and the slip form machine
has to be kept small enough to limit changes in the water content of the concrete mix.
The paving rate has to match the concrete delivery rate, but the consistency of the concrete
and the evenness of the track runways must also be taken into consideration. In practice, the
optimum speed of the paving machine lies between 0.75 and 1 m/min. A steady progress of
the paving operations without detrimental interruptions guarantees quality, whatever type of
machine is used.
All regulating devices of the paving machine have to be tuned before any paving is started.
However, this regulation should also be monitored during the entire course of the paving
process and adjusted if necessary, so that the concrete pavement is executed correctly:
thickness, flawless edges, surface smoothness.
Some machines are equipped with a dowel bar inserter or an anchor bar (also called tie-bar)
inserter. Dowel bars are inserted in the fresh concrete down to the correct elevation after the
vibrator but before the tamper bar. The dowel bar inserter preferably operates in a continuous
operation. Every precaution must be taken to place the dowels correctly and not to disrupt the
evenness of the concrete surface (composition of the concrete, paving speed, etc.).
The use of a 'super smoother' (longitudinal floating tool) is highly recommended and in some
specifications it is even made compulsory whenever a slip form paver is used and especially
for pavements for high speed roads. The super smoother is a beam float suspended from the
backside of the slip form machine and that moves back and forth in the longitudinal direction
while simultaneously traversing the freshly finished concrete surface. It allows to eliminate
small finishing errors or any remaining high and low spots behind the slip form paver. This
improves the driving comfort and limits the nuisance caused by unevenness's with a short
wave length (noise, vibrations). Small traces of cement slurry produced after the passage of
the super smoother, are subsequently removed by dragging a section of burlap or a drag plate.
The super smoother can also be used for other road categories, including bicycle paths.
MEASURES TO OBTAIN A GOOD EVENNESS
A good evenness depends primarily on the following factors:
a concrete mix with an uniform consistency, adapted to the paving machines and the
a regular supply of concrete and a uniform spreading in front of the paver,
correct operation of the paving machines, which in turn depends on the setting of the
forms or the sensor lines, the quality of the track runways, the regulation of the
steady progress of the paver, without interruptions and with a speed compatible with
the consistency of the concrete and the working circumstances,
use of specific tools or equipment to eliminate small bumps after the paving machines:
correction beam, super smoother, etc.
EXECUTION OF JOINTS
All the equipment that is necessary to make joints in the fresh or hardened concrete must be
present at the construction site.
The saw blades have to be suitable to the quality of the concrete, i.e. to the hardness and the
abrasion resistance of the aggregates. It is useful to have spare equipment available in case of
The beam for making a construction joint shall be rigid and shall allow the realization of a
straight joint perpendicular to the axis of the road. This beam has to be adapted to the type of
pavement (jointed pavement, continuously reinforced concrete pavement).
1. CONTRACTION JOINTS
Crack onsets are executed to avoid uncontrolled (“wild”) cracking of the concrete by
shrinkage. Contraction joints have a crack onset which extends to a depth of one third of the
slab thickness and can be equipped with dowels.
On main roads, the contraction joints are usually made by sawing. The saw cutting should
occur as soon as possible, usually between 5 and 24 hours after placement of the concrete. It
is obvious that the concrete should have hardened sufficiently in order to prevent the edges of
the joint from being damaged. In case of high temperatures, special equipment is available to
execute saw cutting within 3 hours subsequent to the placement of the concrete. In that case,
light equipment is used to make saw cuts of about 2.5 cm deep. Every saw cut that has not
instigated a crack within 24 hours is deepened up to 1/3 of the slab thickness.
Making crack onsets for contraction joints in the fresh concrete is a technique that is
practically no longer applied except for country roads or municipal roads whenever the traffic
intensity and evenness requirements permit so.
To make such a joint, a thin steel blade (no more than 6 mm thick) is vibrated into the fresh
concrete to a depth of 1/3 of the slab thickness.
The joint can be made both with flexible and with rigid joint strips. In the first method, a thin
plastic strip twice as wide as the depth of the crack point plus 2 cm is laid on the fresh
concrete. The steel blade is positioned in the middle of the strip and is subsequently vibrated
into the fresh concrete. In the second method the rigid joint strip is inserted into a groove
priory made by vibrating the steel blade in the concrete. The top of the strip must be flush
with the pavement surface.
After having made the crack onset, the concrete surface along the joint should be smoothened
again. However, manual corrections should be kept to a minimum as much as possible, since
they can cause spalling of the joint edges later.
2. EXPANSION JOINTS
Expansion joints are only used exceptionally. In these rare cases, they have to meet the
necessary requirements so as not to cause difficulties later.
The execution of expansion joints requires special attention when using slip form paving
Special attention shall be paid to the following:
the wooden joint filler board shall be firmly attached to the base by means of metal
stakes, so that it cannot move while the concrete is being placed;
the height of the joint filler board shall be slightly(2 to 3 cm) shallower than the
thickness of the concrete slab, in order not to hinder the placement of the concrete. As
soon as the slip form paving machine has passed, the concrete above the joint filler
board shall be removed over a width at least equal to the thickness of the board, so
that no “concrete arch” is made at the top of the joint;
expansion joints shall always be provided with dowels, even for roads with less
intense traffic. At one end of each dowel a cap filled with a compressible material
accommodates the movements of the concrete.
3. CONSTRUCTION JOINTS
Construction joints also called end-of-day or working joints - are made at the end of the daily
production or when the paving process is interrupted for at least 2 hours. The face of these
joints is plane, vertical and perpendicular to the axis of the pavement. They are always
Upon resuming the paving the fresh concrete is placed against the concrete that has already
hardened. The concrete is consolidated on both sides of the joint with a separate manual
Longitudinal joints run parallel to the axis of the road and are only necessary if the pavement
is wider than 4.5m. They can be provided with tie bars.
1. LONGITUDINAL CONTRACTION / BENDING JOINTS
These joints are realised between adjacent concrete lanes that are executed simultaneously.
They are saw cut in the hardened concrete, no later than 24 hours after the concrete has been
placed. The depth is at least 1/3 of the thickness of the slab.
2. LONGITUDINAL CONSTRUCTION JOINTS
These are joints between two adjacent concrete lanes that are executed successively.
Curing is the process of increasing hydration in cement; after setting the concrete, curing
process is done till 20 to 25 days.
There are some method of curing-
Shading concrete works
Covering with hessian & gunny bags
Sprinkling of water
PROTECTION OF THE CONCRETE PAVEMENT
1. PROTECTION AGAINST DRYING OUT
The quality of hardened concrete, and in particular, the durability of the surface, depends
directly on the protection of the fresh concrete against drying out. It is detrimental both to the
strength and to the shrinkage (risk of cracks forming) and also to the durability when the
fresh concrete loses water. As a result of their large exposed areas, pavements are greatly
subjected to drying out. E.g. at an ambient temperature of 20°C, a relative humidity of 60 %,
a temperature of the concrete of 25°C and a wind speed of 25 km/h, 1 litre of water will
evaporate every hour from every m2of pavement surface. Note that the upper surface layer (a
few cm thick) of the concrete only contains about 4 litres of water per m2.
A curing compound is usually used to protect road concrete against drying out . This
coating is sprayed on the concrete top surface and on the vertical surfaces immediately after
the paving train has passed and, if applicable, after the concrete surface has been broomed.
In case of an exposed aggregate finish, the setting retarder must also have the property that it
protects the concrete against drying out. If not, the concrete must be covered with a plastic
sheet as soon as the setting retarder is applied. As stated above, subsequent to the removal of
the skin of concrete mortar, the concrete is protected against drying out a second time by
spraying a curing compound or by covering the surface with a plastic sheet. The latter method
is particularly used in urban areas on coloured exposed aggregate concrete.
The curing compound has to be applied at a rate of at least 200 g/m2 and its effectiveness
coefficient shall be greater than 80%. Curing compounds are pigmented white or have a
metallic gloss so as to better reflect sunlight which limits the warming up of the concrete.
2. PROTECTION AGAINST RAIN
Concreting is stopped if it rains. Furthermore, the necessary measures have to be taken to
prevent that the concrete surface is washed out by rain. This applies both to freshly spread
concrete that has not been compacted yet and to smoothed concrete. Plastic sheets or mobile
shelters are suitable means of protection.
3. PROTECTION AGAINST FROST
When concrete is placed in cold weather (see also § 8.4.1) the pavement surface has to be
effectively protected against frost in such a way that the temperature at the surface of the
concrete does not drop below + 1 ºC for 72 hours after placement. This protection can consist
of, for example, non-woven geotextile or polystyrene foam plates with ballast.
4. PROTECTION AGAINST MECHANICAL INFLUENCES
Every necessary measure shall be taken to protect the fresh concrete from damage due to all
kinds of mechanical influences (cars, bicycles, pedestrians, animals, etc.).
In urban areas these measures are even more necessary.
It must always be ensured that the concrete is processed as quickly as possible, certainly
within 2 hours after batching including the surface treatment and the protection measures. In
hot, dry weather an even shorter workability time has to be observed (maximum 90 minutes).
Unless special precautions are taken that have been approved by the manager of the works,
concrete can only be laid if the air temperature at 1.5 m above ground under thermometer
shelter does not exceed 25°c.
Furthermore, all necessary measures shall be taken to keep the water content of the concrete
as constant as possible from the time of batching until completion of the placement.
Whenever the supply of concrete is interrupted, the driver of the paving machine shall
immediately take the necessary measures to lower the speed of the paving train and to ensure
that the machine stops as little as possible.
For a short interruption, the machine should be stopped before the deposited concrete in the
vibrating chamber has dropped to such a level that the vibrators become visible. If the supply
is interrupted for more than 60 minutes (45 min. in hot weather), a construction joint has to
Upon a long-lasting defect of the paving equipment, the supply of fresh concrete has to be
stopped immediately and an attempt must be made to complete the current paving phase. If
the circumstances and the elapsed workability time no longer make a proper completion
possible, the concrete, that has been deposited but not yet finished, has to be removed.
To achieve a continuous profile, particular care is taken of the execution of the construction
joints, both at the end of the day and every time work is resumed. The concrete is compacted
preferably with a separate vibrating needle before the paving machine is passing in order to
obtain properly compacted concrete on both sides of the joint.
PLACEMENT OF CONCRETE ON A SLOPE
When placing concrete on a slope of less than 4 % it is recommended to work uphill, in order
to prevent tension cracks at the surface. Furthermore, the consistency of the concrete and the
working speed of the paver have to be adapted to the working conditions.
However, if the longitudinal slope is more than 4 %, unevenness can occur as concrete falls
back when the machines have passed. In that case, a suitable composition of the concrete mix
has to be realized and it is recommended to work downhill. It must be ensured that enough
concrete is deposited in front of the paving machine to prevent the concrete from sliding
down. Concrete pavements have been successfully executed on slopes of 10 to 12 %. At one
time the slope was even 18 %.
OPENING TO TRAFFIC
Usually, a concrete pavement is only opened to traffic 7 days after the concrete has been laid
and after, in the presence of all parties, any possible cracks have been recorded. A concrete
pavement of less than 7 days old, can be opened to traffic if the contractor provides proof that
the concrete has reached the minimum compressive strength stipulated in the specifications.
Presently, special compositions of the concrete mix allow an early opening to traffic, i.e.
between 24 and 48 hours after placement. These mixes are used, for example, for pavement
repair works to reduce the nuisance to the public as much as possible.
It is pointless to talk about quality if not all employees, each at his own level, make a special
effort to understand the rules of good practice, upgrade their know-how and act accordingly.
COST ANALYSIS OF RIGID PAVEMENTS
The selection criteria of type of pavement, flexible or rigid, should be based not on the initial
cost of construction but life cycle cost, which includes the discounted maintenance and
pavement strengthening costs that are incurred during the design life of the pavement.
This is the cost of construction of the pavement which mainly depends upon the pavement
thickness, governed by the strength of sub grade soil and traffic loading, cost of materials and
cost of execution of the work. the above have a wide range of variability across the country
and is difficult to generalise.
The maintenance cost includes the maintenance of pavement during the design life of
pavement to keep the pavement at the specified service level.
In case of rural roads, maintenance of these roads is to be done by the respective state
government from its available financial resources. most of the states have poor past
performance record to maintain such low volume roads through other schemes, mainly
because of having inadequate funds for maintenance of road infrastructure in the state.
LIFE CYCLE COST ANALYSIS
Life cycle cost analysis can be defined as a procedure by which a pavement design alternative
will be selected , which will provide a satisfactory level of service at the lowest cost design
RIGID PAVEMENT DESIGN AND COSTOF CONSTRUCTION PER
The design of rigid pavement depends upon the CBR value of sub grade , design axle load of
commercial vehicles during the design life, which is generally 20 years or more for rural
roads, a typical pavement composition for rural road is given below :( refer: SP:62-2004):
MAINTENANCE COST OF RIGID PAVEMENT
The average yearly maintenance cost of rigid pavement will be about Rs. 10000per km for a
single lane rural road to cover filling of sealing compound in the joints, requires of concrete
LIFE CYCLE COST ANALYSIS OF RIGID PAVEMENT
Period of analysis has been considered as 20 years, being the design life of concrete
pavement in rural area. the discount rate of 10% has been taken. inflation rate of 5% has been
considered for future rise in prices of materials.
CEMENT CONCRETE PAVEMENT VS BITUMINOUS
PAVEMENT- A COST ANALYSIS
India„s economical growth plan of over 6% per annum for the next 20 years will, to a great
extent, depend on an efficient road infrastructure, not only national highways but other roads
too, including link roads for rural connectivity, which can provide fast movement of goods
and people with safety and economical cost to the user. government of India has drawn up
Pradhn Mantri gram Sarak Yojana(PMGSY) for implementation of rural connectivity. it is
estimated that in the next 7 years, road works under PMGSY worth Rs. 1,20,000 crores are to
be constructed .
Since road pavements are an important part of these projects, costing about 50% of the
investment , a careful evaluation of the alternatives is necessary to make the right choice on a
rational basis, which may be comparatively more beneficial to the nation.