Traning report on pwd cement concrete road pavement
1. A Summer Training Report
On
Construction of Cement Concrete Road Pavement
At
UTTAR PRADESH PUBLIC WORKS DEPARTMENT
CONSTRUCTION DIVISION-1,GORAKHPUR
Submitted for Partial fulfillment for the award of degree
Bachelor of Technology
In
CIVIL ENGINEERING
Submitted to: - Submitted By:
Civil Department Niwashish Vishwas
VITSGZB BTech 4th
Yr
Roll No:-1422300014
Vivekanand Institute Of Technology & Science, Ghaziabad
Affiliated to
Dr. A.P.J. Abdul Kalam Technical University, Uttar Pradesh,
Lucknow
2. AKNOWLWDGEMENT
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 Assistant Engineer
and
Junior Engineer Mr. RAJESH KUMAR and Mr. P.S. PATEL 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 Building block-1 P.W.D. Gorakhpur (U.P.) Department for their
kind support. They have always been a source of inspiration to me.
DATE: - 20/07/2017 NIWASHISH VISHWAS
3. TABLE OF CONTENT
S NO. CONTENT PAGE NO
1 PUBLIC WORKS DEPARTMENT: AN OVERVIEW 5
2 INTRODUCTION 6
3 WHAT IS ROAD OR PAVEMENT 9
4 SITE CLEARANCE 15
5 PLANTS AND EQUIPMENTS 16
6 MINERALS USED 19
7 TEST 25
8 PROPORTIONING 32
9 PROCEDURE TO CONSTRUCT PAVEMENTS 33
10 PREPARATION OF THE SUB- GRADE OR BASE COARSE 34
11 MIXING AND TRANSPORT OF CONCRETE 35
12 SURFACE COURSE 37
13 PLACING THE CONCRETE 39
14 EXECUTION 40
15 MEASURES TO OBTAIN A GOOD EVENNES 44
16 EXECUTION OF JOINTS 45
17 CURING 49
18 SPECIAL MEASURES 52
19 OPENING THE TRAFFIC 55
20 COST ANALYSIS OF RIGID PAVEMENTS 55
21 CEMENT CONCRETE PAVEMENT VS BITUMINOUS
PAVEMENT-A COST ANALYSIS
57
22 CONCLUSION 59
23 REFERENCE 59
4. 1. PUBLIC WORK DEPARTMENT:AN OVER VIEW
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 Work.
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.
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5. 2.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. 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 categories.
National Highways (NH)
State Highways (SH)
Major District Roads (MDR)
Other District Roads (ODR)
Village Roads (VR)
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6. 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 trafficpoint
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
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7. 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.
Fig (1) National Highway (NH)
8
8. Fig (2) Major District Road (MDR)
Fig (3) Village Road (VR)
3.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-
The impact of traffic, particularly heavy vehicles.
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9. Environmental factors such as weather, pollution.
PURPOSE
Many people rely on paved roads to move themselves and their products
rapidly and reliably.
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, ravelling and unevenness which makes the pavement
unsuitable for use.
➢ 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.
10
10. ➢ 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.
➢ Cement concrete roads save a substantial quantity of stone aggregates
and this factor must be considered when a choice pavements ismade.
➢ Concrete roads can withstand extreme weather conditions – wide
ranging
temperatures, heavy rainfall and water logging.
11
11. ➢ 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 semiself- compacting concrete techniques and the use of closely
spaced thin joints. R&D efforts should be initiated in this area.
12
12. 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
13
13. 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 be limited.
14
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.
14. 4.SITE CLEARANCE
General:
Site clearing generally consists of the cutting and/or taking down,
removal and disposal of everything above ground level, including
objects overhanging the area to be cleared such as tree branches, except
such trees, vegetation, structures or parts of structures and other things
which are designated in the contract to remain or be removed by others
to which the engineer directed to be left undisturbed.
The material to be cleared usually but not necessarily is limited to
trees, stumps, logs, brush, undergrowth, long grasses, crops, loose
vegetable matter and structure.
The entire road area shall be cleared as described above, unless
otherwise shown on the drawing and/or directed by the engineer.
Setting out:
The right of way (R.O.W) shall be surveyed and set out before anysite
clearance is cleared out. Wooden pegs usually indicate the surveyed
rights of ways.
Procedure for setting out:
1. Fixing of centre line of alignment by using total station, theodelite.
2. Calculating curvature and refractures (for curves and embankment) by
using auto levels or dumpy level.
3. To establish traverse bench mark (TBM) at required intervals adjacent
to alignments..
4. To mark the longitudinal and cross sectional pavement structure.
5. To make efficient, minimum and desired sight distance at major
conflicts and terrain and also setting out of horizontal curves
throughout the alignment was done by using theodolite and total
survey station
15
.
15. Steps involved in surveying:
Benchmark
Temporary benchmark at regular intervals.
Centre line marking
Road markings
Profile marking (for longitudinal and cross sectional structures)
Establishment of different levels providing gradients as per to
design considering different factors like-
Surveying using dumpy level.
5. PLANTS AND EQUIPMENTS
Site clearing of trees, vegetation, undergrowth, bushes and minor structures
are carried out by dozers and or hydraulic excavators. Trees that cannot be
felled by the aforesaid equipment shall be felled by using saws.
Major structures that cannot practically be cleared by hydraulic excavators
and/or dozers, these demolitions can be carried out using pneumatic tools,
explosives and/or otherspecialized equipment depending on the size and type
16
16. of structures. Before commencing explosive demolition all necessary permits
and licenses will be obtained and a blasting plan detailing the size of charges,
locations of holes, system of detonation and safety precaution will be
forwarded to the engineer together with the request sheets.
17
17. Sequence of works:
Prior to the commencement of the site clearance, the following shall be
carried out either independently or jointly with the Engineer’s
Representative.
(I) The right of ways (R.O.W) shall be surveyed and set out according to
the data stated in the drawings.
(II) Photographs shall be taken of structures, landscaping trees and shrubs,
fences, telephone and electrical poles and other if they are payable under
individual measured item apart from the general site clearance in the bill
of quantities.
(III) The above site clearance items shall be measured according to the
method of measurement jointly with the Engineer’s Representatives.
The location of these items shall be identified according to the survey
data or offsets from the centerline of the proposed alignment in road
construction.
(IV) Prior to demolition of existing buildings, liaison with the respective
authorities terminates the utilities supply to the building.
(V) Removal of landscaping trees and shrubs shall be carried out with the
prior approval of the concerned authority.
(VI) Fencing or others that are to be relocated or salvaged shall be carried out
according to the drawings or as per the instructions given by Engineer.
(VII) Obtain confirmation that the employer or relevant authority have
acquired the right of way lands.
(VIII) Access roads to the site shall be constructed if required to enable
vehicles, equipment and plants to be brought in it.
(IX) Solid waste dumps sites shall be predetermined within or outside the site
for the dumping of the site clearing materials.
(X) The site clearance then shall be proceeded to clear the trees,
vegetation, undergrowth, bushes and minor structures by hydraulic
excavators or dozers.
18
18. 6. MINERALS USED
Concrete is widely used in domestic, commercial, recreational, rural
and educational construction. 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
Sand
Aggregate
CEMENT
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 nonhydraulic. 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
19
19. 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
building material.
Portland cement
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.
20
20. 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
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
nontropical coastal settings is silica (silicon dioxide, or SiO2), usually
in the form of quartz. The second most common type of sand is
21
21. 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.
AGGREGATE
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.
22
22. 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
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
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.
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23. COARSE AGGREGATE
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.
24
24. Aggregate Equation
7. Test
There are four main tests to be done on concrete:
1- Compression Test
2- Impact Test
3- CBR test
4- Cube Test
5- Slump test
25
25. I. THE COMPRESSION TEST
The compression test shows the compressive strength of hardened
concrete. The testing is done in a laboratory off-site. The only work
done on-site is to make a concrete cylinder for the compression test.
The strength is measured in Megapascals (MPa) and is commonly
specified as a characteristic strength of concrete measured at 28 days
after mixing. The compressive strength is a measure of the concrete’s
ability to resist loads which tend to crush it.
Tools
Cylinders (100 mm diameter x 200 mm high or 150 mm diameter x 300
mm high)
( The small cylinders are normally used for most testing due to their
lighter weight )
Small scoop
Bullet-nosed rod (600 mm
x 16 mm) Steel float Steel
plate
Method
1 Clean the cylinder mould and coat the inside lightly with form oil,
then place on a clean, level and firm surface, ie the steel plate.
2 Collect a sample.
3 Fill 1/2 the volume of the mould with concrete then
compact by rodding 25 times. cylinders may
also be compacted by vibrating using a
vibrating table.
4 Fill the cone to overflowing and rod 25 times
into the top of the first layer, then top up the mould
26
26. till overflowing.
5 Level off the top with the steel float and concrete from around the
world.
6 cap clearly and put in a cool dry place tag cylinder to set for atleast
24hr
7.After the mould is removed the cylinder is sent to the
laboratory where it is cured and crushed to test
II. IMPACT TEST
This test is done to determine the aggregate impact value of coarse
aggregates as per IS: 2386 (Part IV) – 1963. The apparatus used for
determining aggregate impact value of coarse aggregates is
Impact testing machine conforming to IS: 2386 (Part IV)- 1963,IS Sieves
of sizes – 12.5mm, 10mm and 2.36mm, A cylindrical metal measure of
75mm dia. and 50mm depth, A tamping rod of 10mm circular cross
section and 230mm length, rounded at one end and Oven.
Preparation of Sample
i) The test sample should conform to the following grading:
– Passing through 12.5mm IS Sieve – 100%
– Retention on 10mm IS Sieve – 100%
ii) The sample should be oven-dried for 4hrs. at a temperature of 100 to
110oC and cooled.
iii) The measure should be about one-third full with the prepared
aggregates and tamped with 25 strokes of the tamping rod.
A further similar quantity of aggregates should be added and a further
tamping of 25 strokes given. The measure should finally be filled to
overflow, tamped 25 times and the surplus aggregates struck off, using a
27
27. tamping rod as a straight edge. The net weight of the aggregates in the
measure should be determined to the nearest gram (Weight ‘A’).
Procedure to determine Aggregate Impact Value
i) The cup of the impact testing machine should be fixed firmly in
position on the base of the machine and the whole of the test sample
placed in it and compacted by 25 strokes of the tamping rod.
ii) The hammer should be raised to 380mm above the upper surface of
the aggregates in the cup and allowed to fall freely onto the aggregates.
The test sample should be subjected to a total of 15 such blows, each
being delivered at an interval of not less than one second
3. CBR TEST
Tests are carried out on natural or compacted soils in water soaked or un-
soaked conditions and the results so obtained are compared with the
curves of standard test to have an idea of the soil strength of the subgrade
soil.
PROCEDURE
Normally 3 specimens each of about 7 kg must be compacted so
that their compacted densities range from 95% to 100% generally
with 10, 30 and 65 blows.
Weigh of empty mould
28
28. Add water to the first specimen (compact it in five layer by giving
10 blows per layer)
After compaction, remove the collar and level the surface.
Take sample for determination of moisture content.
Weight of mould + compacted specimen.
Place the mold in the soaking tank for four days (ignore this step
in case of unsoaked CBR.
Take other samples and apply different blows and repeat the
whole process.
After four days, measure the swell reading and find %age swell.
Remove the mould from the tank and allow water to drain.
Then place the specimen under the penetration piston and place
surcharge load of 10lb.
Apply the load and note the penetration load values.
Draw the graphs between the penetration (in) and penetration load
(in) and find the value of CBR.
Draw the graph between the %age CBR and Dry Density, and
find CBR at required degree of compaction.
29. III. CUBE TEST
Test applied to the concrete, this is the utmost important which gives an
idea about all the characteristics of concrete. By this single test one judge
that whether Concreting has been done
properly or not. For cube test two types of specimens either cubes of
15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the
size of aggregate are used. For most of the works cubical moulds of
size 15 cm x 15cm x 15 cm are commonly used.
This concrete is poured in the mould and tempered properly so as not
to have any voids. After 24 hours these moulds are removed and test
specimens are put in water for curing. The top surface of these
specimen should be made even and smooth. This is done by putting
cement paste and spreading smoothly on whole area of specimen.
These specimens are tested by compression testing machine after 7
days curing or 28 days curing. Load should be applied gradually at the
rate of 140 kg/cm2 per minute till the Specimens fails. Load at the
failure divided by area of specimen gives the compressive strength of
concrete.
APPARATUS
Compression testing machine
PREPARATION OF CUBE SPECIMENS
The proportion and material for making these test specimens are from
30. The same concrete used in field.
SPECIMENT
6 cubes of 15 cm size Mix. M15 or above
IV. SLUMP TEST
The slump test is done to make sure a concrete mix is workable.
Workability measures how easy the concrete isto place, handle and
compact.
Standard slump cone (100 mm top diameter x 200 mm bottom diameter x
300 mm high) Small scoop Bullet-nosed rod mm long x 16 mm diameter (
600 ) Rule Slump plate (500 mm x 500 mm)
Method
1 Dampen with water and place on the slump plate.
C lean the cone.
The slump plate should be clean, firm, level and non-absorbent.
2 Collect a sample.
3 Stand firmly on the footpieces and fill 1/ 3 the volume of the cone with
the sample.C ompact the concrete by 'rodding' 25 times.
Rodding
Rodding means to push a steel rod in and out of the
31. concrete to compact it into the cylinder, or slump cone.
Always rod in a definite pattern, working from outside into the middle.
4 Now fill to 2/3 and again rod 25 times, just into the top of the first layer.
5 Fill to overflowing, rodding again this time just into the top Top up the
cone till it overflows. o f the second layer.
6 Level off the surface with the steel rod using a rolling Clean any concrete
from around actio n.
the base and top of the cone, push down on the handles and step off the
footpieces.
7 Carefully lift the cone straight up making sure not to move the sample.
8. PROPORTIONING
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 .
32. 9. 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.
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33. 10. PREPARATION OF THE SUB- GRADE OR BASE COARSE
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 pavement structure.
For roads with a base, drainage of the water must be provided. Mud,
leaves, etc. have to be removed.
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
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34. latter work must be done with care, to prevent the sheet from tearing
or being pulled loose by the wind.
11. 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
35
35. 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 used. 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 operations.
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.
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36. 12.SURFACE COURSE(WMM)
General:
Wet mix macadam (WMM) is a base material in road pavement structure,
which is batched from a mixing plant, and laid in position with a paver.
Materials:
WMM consists of crushed graded aggregate and granular material pre
mixed
with water.
Equipments:
Constructional plants required are as follows:-
A) WMM MIXING PLANT 1
B) PAVER 1
C) MOTOR GRADER 1
D) VIBRATORY ROLLER 1
E) TIPPER 3
Procedures:
Work shall commence on site upon Approval and Acceptance of the sub-
base layer.
The wet mix macadam shall be plant mixed with moisture content within
reasonable limits of the Optimum Moisture Value, as determined in
accordance with IS 2720 (Part 8).
The approved wet mix macadam shall be delivered to site by tipper
trucks. To prevent the loss of moisture, the materials shall be covered, if
necessary.
(i) The wet mix macadam shall be laid by using a paving machine.
(ii) Segregation at localized areas shall be made good by back casting
with fines or by immediate removal and replacement of the freshly laid
wet mix macadam.
(iii) Transverse joint shall be lapped and longitudinal joints due to
stoppage of work will have the loose removed before paving resumes.
37. (iv) Compaction shall be carried out using vibratory roller and as per
specifications.
(v) The surface of the wet mix macadam shall be finished to the grade
and line as required by the drawings, and within specified tolerance
limits.
(vi) On completion of laying and compaction, approval of the Engineer
will be obtained for compliance with the specified requirement, before
proceeding with the next layer.
(vii) Sampling of mixture shall be carried out at the plant or site.
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38. 13.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
PREPARATIONOF 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 deformations;
good skid resistance to prevent the tracks from slipping, especially
when paving on a slope;
good evenness to avoid that the self-levelling systems have to
compensate for
39
39. 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 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
40
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 greatest width of the paving machine plus an
extra width (especially on
the necessary space for placing the sensor lines.
14.EXECUTION
40. 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 steel;
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
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41. 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.
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43. 15. 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 working circumstances,
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 sensors, etc.,
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
. 44
44. 16. 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 a defect. 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).
TRANSVERSE JOINTS-
45
45. 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.
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46. 1. 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 machines.
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.
2. 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 doweled. Upon resuming the paving the fresh concrete is
placed against the concrete that has already hardened. The concrete is
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47. consolidated on both sides of the joint with a separate manual needle
vibrator.
LONGITUDINAL JOINTS
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.
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48. 17.CURING
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
By ponding
Membrane curing
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49. 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
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50. 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.
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51. 4. PROTECTION AGAINST MECHANICAL INFLUENCES
(TRAFFIC SIGNPOSTING)
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.
18. SPECIAL MEASURES
WORKABILITY PERIOD
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
.
PAVING INTERRUPTIONS
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
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52. construction joint has to be made. 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 %
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.
54. 19. 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.
20. 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.
INITIAL COST
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.
55
55. MAINTENANCE COST
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 life.
RIGID PAVEMENT DESIGN AND COSTOF
CONSTRUCTION PER KILOMETERS
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):
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58. 22. CONCLUSION
India 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.
23. REFERENCE
www.Google.com
www.concrete.net.au
www.res.gov.in
www.upjl.com
www.concrete.com
www.sand.uk
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