Road Construction Technology December 2014 Road Construction Technology Prepared by- Er. Dipesh Pandey

CONTENTS Introduction Activities in Road Construction Tools, Equipment and Plant Earthwork Mass Haul Diagram

Definition Activities to change existing ground to designed shape, grade and provide necessary facilities for smooth, safe and efficient traffic operation, including reconstruction of existing road.

Activities in Road Construction Earthwork site clearance, E/W in filling, E/W in excavation, Excavation for borrow pit, Excavation for foundation, Disposal of surplus Structural Work Earth retaining str, Gully control works, Land slide stabilization, River training works, Bridge protection works Pavement Work Sub grade preparation, Sub-base, Base course and Wearing course Miscellaneous Work Road Ancillaries Traffic sign/signal, markings Boi-engineering works Drainage Work Side drains, Culverts, Sub surface drain, Causeway Minor bridge

Tools, Equipment and Plant Hand shovel, Chisel, Peak, Spade, Hand Rammer, Brushes, Trowel, Wheel Borrow Equipment Earth Moving Equipment Dozer, Scraper, Loader, Excavator, Backhoe, Dragline, Clamshell, Trench digger Leveling Equipment Motor Grader Paving Equipment Binder storage tank with heating device, binder spreader, aggregate spreader, cement concrete mixture, bituminous mechanical paver, cement concrete paver Compaction Equipment smooth wheel roller, vibrating roller, pneumatic roller, sheep foot roller, different capacity rammers

Cont.… Transporting Equipment Lifting Equipment Loader, Backhoe, Dumping trucks, Flat body trucks, mini dumper Lifting Equipment Loader, Backhoe, Different capacity crane Leveling Equipment Motor Grader Paving Equipment Binder storage tank with heating device, binder spreader, aggregate spreader, cement concrete mixture, bituminous mechanical paver, cement concrete paver Miscellaneous Equipment Rock driller, Core Cutter, Edge cutter

Cont.…. Plants Cement concrete plant, Asphalt concrete plant, cold mix plant, Aggregate crushing plant, Screening plant,

Earthwork Process to prepare sub grade level bringing it to design grade and shape may be in embankment and filling Quantity based on longitudinal and cross section Mass haul diagram necessary to decide economic haul E/W quantities are estimate based on L and X sections

Site Clearance Started just after survey works and before any construction works Clearing of grass, weeds, bushes, shrubs Removal of existing trees, stumps and roots along the road alignment Removal of existing structures along right of way

Earthwork in Filling Reasons: Necessary when we have to raise the sub-grade from existing ground level Reasons: To keep sub-grade high from ground water table To prevent damage due to surface and capillary rise To maintain vertical alignment

Design elements: Height, Fill material, Settlement, Stability of foundation, Stability of slope Equipment: Grader, Roller, Tripper and water tanker or manually for small project

Construction steps: Laying layer by layer Grading each layer Attaining desired density before next layer is placed The thickness of the layers may vary between 10 to 30 cm depending on various factors such as soil type, equipment, specifications etc. Quality Control Checking of suitability of filling material Checking of field moisture and dry density of each layer (> 93 % for below and > 95% for above) Proper finishing of formation slope as per design

E/W in Excavation In the process of cutting or loosening and removing earth including rock from its original position, transporting and dumping it as a fill or spoil bank. Also includes excavation for side drains Earth excavation work may be divided as excavation or cutting, grading and compaction.

Design Elements Equipment Depth, Stability of foundation, Stability of slopes, Accommodation of road side drain Equipment Grader, roller, tipper and water tanker

Construction Steps Quality Control Excavation Grading of sub-grade layer Compaction with roller Quality Control Fixing reference pegs Checking field moisture and dry density Proper finishing of formation slopes

Field Control of compaction Measurement of moisture content Measurement of max. dry density corresponding to optimum moisture content

Planning of E/W Mass haul Diagram Earthwork for a highway project involves cuts and fills. The most balanced design is one which utilizes the cut volumes in the adjacent fills. This is achieved by a mass haul diagram which is a graphical representation of amount of cut and the fill and the manner in which the earth is to be hauled from cut to fill.

Planning of E/W Mass haul Diagram The ordinate at any station along the MHD indicates the earthwork quantity accumulated up to that point, and is the summation of the differences between cut and fill. The maximum (+) ordinate indicates a change from cut to fill (D) and the minimum (-) ordinate indicates from fill to cut (A and G). Upward sloping curves indicate (rising left to right) indicate a cut Downward sloping (falling left to right) curves occur in a fill section peaks indicate a change from cut to fill and valleys occur when the earthwork changes from fill to cut

If the curve has steep slope it indicates heavy cuts or high fills If the curve has steep slope it indicates heavy cuts or high fills. Flat slopes indicate small earthwork quantities. The balance point is defined as a point where the volume in excavation balances the volume in embankment. Any line drawn parallel to the base line and intersecting two points within the same curve indicates a balance of cut and fill between these two points ( C and D). Such a line (HJ) is called a balancing line.

Haul: it has dual meaning Haul: it has dual meaning. Distance over which material is moved and also the volume distance of material used. Free haul: The certain amount of haulage is included in the earthwork rate itself and the contractor is expected to carry earth over this haulage within his quoted rate. Over haul: the haulage over the free haul distance paid for extra rate called over haul.

Economic over haul: the economic over haul distance can be determined by equating the cost of roadway excavation plus overhaul and tipping in embankment with the cost of borrow pit material plus excavation, haul and wasting of roadway material within the free haul distance a= cost of roadway excavation per cu. m. b= cost of overhaul and tipping per cu. m. c = cost of borrow material per cu. M. L= economic overhaul distance in stations a + b x L = c + a L= c/b

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