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HIGHWAY CONSTRUCTION

HIGHWAY CONSTRUCTION

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HIGHWAY CONSTRUCTION

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  1. HIGHWAYCONSTRUCTION IRC: 58 - 2002, Guidelines for the design of Plain Jointed Rigid Pavements for Highways IRC: 15 - 2002, Code of practice for Construction of Cement ConcreteRoads IRC:44-2008,Guidelinesforcement concrete mix design forpavements IRC:SP62 – 2004, Guidelines for design of CC roads for RuralRoads

  2. Types ofPavements

  3. HIGHWAYCONSTRUCTIONS • Pavement Design • Pavement means surfacing layeronly. • In terms of highway design, it means the total thickness of road including surfacing , base & subbase, ifany. • Thus pavement includes all the structural layers of road structure lying on subgrade of theroad

  4. Parameters for Design ofPavements Designofpavementsmainlyconsists aspects Design mix ofmaterials pavementthickness oftwo

  5. Factors for Design ofPavements • Following factors are responsible for pavementdesign • Climate : rainfall, Temp, Frostaction • Environment : Ht of embankment, foundationcutting • Geometry: • Pavementmaterials:theyhavetoresist conditions ,durability,maintenance. • Subgrade Soil : decides thickness ofpavement • Traffic:Repetitions,Speed,WheelLoads, pressure, volume of traffic , no of vehicles/day. climatic contact

  6. Design Approach for rigidPavements • Variables fordesign • Wheel Loads • Traffic • Climate • Terrain • Subgrade conditions • Properties of CementConcrete

  7. Flexible Rigid

  8. Components of CCpavement

  9. Types of RigidPavements • 1. Jointed Plain Concrete Pavement(JPCP) • – No temperaturesteel • 2. Jointed Reinforced Concrete Pavement(JRCP) • – Temperature steel placed at mid height and discontinued at thejoints • 3. Continuously Reinforced Concrete Pavement(CRCP) • – Not popular in India – verycostly • 4. Prestressed Concrete Pavement(PCP) • – Notpopular

  10. Design Approach for rigidPavements • Cement Concrete roads provides a highly rigid surface and hence for the success of such roads, following two conditions should besatisfied • They should rest on non- rigid surface having uniform bearingcapacity. • The total thickness or depth of the concrete pavement & the non rigid the base should be wheel load on a sufficient to distribute sufficient area of subbase so that the pressure on unit area remains with the permissible SBC of the soil.

  11. Design Approach for rigidPavements • Concrete slab hashigh modulus of elasticity, high rigidity & flexural strength, so wheel loads are distributed over large areas of Subgrade . This leads to small deflections and also leads compressive stresses imposed on the Subgrade. • This leads to fatigue damage in concrete slab in form of development of micro cracks, due to repeated application of trafficloads. • This is arrested by limiting flexural stresses and increasing the Concrete mixgrade.

  12. Design Steps ( parameters) Traffic parameters : Design Wheel load, Trafficintensity Environmental parameters : temp differential ( CRRI table) Foundation strength k ( modulus of subgrade reaction) Foundation surface characteristics ( As per IRC) Concrete characteristics ( IRC :58-1988) Modulus ofelasticity Coefficient of thermalexpansion. Design slabthickness

  13. Purpose of joints in ConcreteRoads To absorb expansion & contraction due to variation in temperature. ( horizontal movements ofslabs) To avoid warping of slabedges To grant facility in construction.

  14. TYPES OFJOINTS • Concrete pavements are provided with Joint in Transverse & Longitudinal directions whic are classifiedas • a) CONTRACTIONJOINTS • b) EXPANSIONJOINTS • d) CONSTRUCTIONJOINTS s h

  15. CONTRACTIONJOINTS • These are purposely made weakened planes which relieve the tensile stresses in theconcrete • Causedduetochangesinthemoisturecontent (Drying shrinkage) and/or temperatureand • Prevent the formation of irregular cracks due to restraint in free contraction of concrete. • They are also providedto • )Relieve stresses due towarping • To permit the contraction of theslab

  16. Details of the contractionjointsare given in IRC:SP62 • They are formed initially by sawing a groove of 3-5 mm with up toabout one-fourth to one-third the slab Details of the contraction joints are given in IRC:SP 62. They are formed initially by sawing a groove of 3-5 mm with up toabout one-fourth to one-third the slab thicknesses. This facilitates the formation of a natural crack at this location extending to the fulldepth. • In order to seal the joint, the top 10-20 mm of this groove is widened to 610mm. • Spacing of contraction joints may be kept at 2.50m to 3.75m. • Length of panel shall not be more than width of panel.

  17. LONGITUDINALJOINTS • Lanes are jointed together by joint known as Longitudinaljoint • Longitudinal joints areprovidedin multilane pavements and also when the pavement is more than 4.5 m wide. • They are provided normally at 3.5m c/cto • 1) Relieve stresses due towarping. • 2) To allow differential shrinkage & swelling moisture • 3) To prevent longitudinalcracking due to changes of subgrade • Procedure ofconstruction • Initially joint is cut to a depth 1/3rd slab Initially joint is cut to a depth 1/3rd slab thick ± 5mm. Tie bars are provided at the joints not for load transference but for keeping the adjoining slabs together. The details of such joints are given in IRC:SP62. • The top 15-20 mm of the joint is sawn to a width of 6-8 mm forsealing

  18. Expansionjoints • There are full-depth joints provided transversely into which pavement can expand, thus relieving compressive stresses due to expansion of concrete slabs, and preventing any tendency towards distortion, buckling, blow-up andspalling. • The current practiceisto provide these joints only when concreteslab • abuts with bridge orculvert. • They allow expansion of slabs due totemperature • TheypermitcontractionofslabsNormalDetailsofthesejointsaregivenin • IRC:SP62. • They are about 20 mm inwidth • A joint filler board of compressible material conforming to IRC:SP:62 is used to fill the gap between the adjacent slabs atthe • joint. • The height of the filler board is such that surface of the pavement. • The joint groove is filled by a sealant. its top is 23-25mm belowthe

  19. Constructionjoints The need for such joint arises when construction work is required to be stopped at a place other than the location of contraction or an expansion joint, due to some breakdown of the machinery or any otherreason. Such joints are of butt type and extend to the full depth of thepavement. The sealing of such joints shall be done in the same manner as for contraction joints, by cutting a groove 10-12 mm wide and 20-25 mmdeep. Generally, suchjointsare avoided in highways. The work is normally terminated at a contraction or expansionjoint

  20. JOINTFILLER • Joint spaces are first filled with compressible filler materials and top of the joints are sealed usingsealer • Joint filler should possess following properties oCompressibility • Elasticity i.e they should be capable of regaining their shape when compression is released • Durability

  21. Load Transfer at TransverseJoints • IRC:58-2001 had adopted equations developed by Friberg for analyzing long beam on elastic foundation (bar embedded in concrete) , for computation of maximum bending stress in the dowel bar & max bearing stress in concrete. • High bearing stress on the concrete surrounding the dowel bar can fracture the same, leading to the looseness of the dowel bar and the deterioration of the transfer system leading to faulting of theslab. • The dowel bars are installed at a suitable spacing across the joints and the system is assumed to transfer 40% of the wheel load.

  22. TYPES OFSEALANTS • Hotpouredrubberized (Thermoplastictype) • Cold applied poly sulphidesealants • Cold siliconeSealants Asphalts

  23. Cleaning of LongitudinalJoint

  24. Fixing of Back up Rod after InitialCut

  25. Widened Groove after 14days

  26. Finished PQC surface with SealedJoints

  27. Desirable Properties of Soil as SubgradeMaterial • Stability • Incompressibility • Permanency ofstrength • Minimum changes in volume and stability under adverse condition of weather and ground water • Gooddrainage • Ease ofcompaction

  28. Cements that can be used as per IRC:44-2008 Any of the following types of cements capable of achieving the design strength and durability may be used with the prior approval of theEngineer. Ordinary Portland Cement, 33 grade, IS:269 Ordinary Portland Cement, 43 grade, IS:8112 Ordinary Portland Cement, 53 grade, IS:12269 PortlandPozzalonaCement(flyashbased,IS: 1489, part1 Portland Slag Cement, IS:455

  29. Fly ash can be as a partial replacement of cement (OPC) up to an extent of35%. Fly ash for blending shall satisfy the following Properties conforming toIS:3812-2004

  30. Advantages in adding FlyAsh Increases CSH ( Calcium Silicate Hydrate) volume Denser CSH formed by secondaryreaction Better Pore structure andcomposition Low heat of hydration Resistance to adverse exposure conditions Reaction when Fly Ash isadded: CS + H  CSH +CaOH CaOH + Fly Ash CSH (cementinggel)

  31. DesignApproachforFlexible Pavements • Traffic is considered in terms of the cumulative number of standard axles (8160 kg) to be carried by the pavement during the designlife • For estimating the design traffic, the following Information isneeded: • Initial traffic after construction(CVPD) • Traffic growth rate during the designlife • By studying the past trends of trafficgrowth • As per the econometric procedure outlined in IRC:108

  32. DesignApproachforFlexible Pavements • Bituminous pavingmixes. • Following factors are involved in design of bituminous pavingmixes • Durability • fatigueresistance • flexibility • fracture or tensilestrength • permeability • Skidresistance • Thermal characteristics

  33. DesignApproachforFlexible Pavements MixDesign Methods Marshall method of MixDesign Hveem method of Mixdesign

  34. DesignApproachforFlexible Pavements • Marshall method of MixDesign • Stability FlowTest • Max load resistance that a Std specimen will develop at 60 DegC Flow is measured as a deformation or total amount in units of 0.25 mm between no of load & maximum during the stability test expressed as 0.10 mm

  35. DesignApproachforFlexiblePavements • Marshall method of Mix Designcriteria

  36. DesignApproachforFlexible Pavements Hveem method of Mix design This method of mix design starts with obtaining an estimate of optimum bitumen content by use of Centrifuge Kerosene equivalent (C.K.E) The % of kerosene retained in the aggregate afterbeing soaked and centrifuged as a specified is called C.K.E value & charts are available to find out the optimum bitumen content from C.K.Evalue

  37. DesignApproachforFlexible Pavements • Hveem method of Mixdesign • It consists of 3 tests on bituminous samplesof 100 mm diameter & • 63.50 mm ht. Each specimen is tested for subsequenttests • Following tests areconducted SwellTest StabilometerTest Cohesive meterTest 100 mmdia • Swell should not be <0.76mm 63.50mm • Stabilometer values for light, medium, heavy should be 30,35 & 67 respectively • Cohesive meter value should not be more than50 • Air voids % should have minimum value of4%

  38. Methods ofDesign Design ApproachforFlexible Pavements Group Index Method ( G I) California Bearing ratio ( C B R )Method

  39. DesignApproachforFlexible Pavements Group IndexMethod • GI is a arbitrary index given to the type of soil and is based on % of fines ,liquid limit, and plasticity index of thesoils • GI values range from 0 to20 • Greater GI value, poorer thesoil

  40. DesignApproachforFlexible Pavements Group IndexMethod