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Traning report on pwd cement concrete road pavement

hello frends i am NIWASHISH VISWAS from VITS GZB this is my
industrial traning report at pwd cement concrete road pavement

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Traning report on pwd cement concrete road pavement

  1. 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. 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
  4. 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. 5
  5. 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) 6
  6. 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 7
  7. 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. 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. 9
  9. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 23
  23. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 33
  33. 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 34
  34. 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. 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. 36
  36. 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. 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. 38
  38. 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. 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. 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 41
  41. 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. 42
  42. 42. 43
  43. 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. 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. 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. 46
  46. 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 47
  47. 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. 48
  48. 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 49
  49. 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 50
  50. 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. 51
  51. 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 52
  52. 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 % 53 .
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  54. 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. 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): 56
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  58. 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 59