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CEMENT ROAD CONSTRUCTION

Construction of Cement Concrete Road

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Using mix Concrete , there are some steps to construct the road-

1. Preparation of base2. Form working3. Preparation of subgrade4. Watering of base5. Joints6. Material mix & placing7. Compaction

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8. Finishing of surface8A. Floating8B. Belting8C. Brooming9. Curing10. Joint filling11. Edging12. Open to traffic

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1. Preparation of subgrade

1. Rolling on sub grade by roller2. Filling the granular soil in the weak part and pot

holes3. Correct the soil coat , Camber , longitudinal

slope When concrete direct laid on subgrade, For preventing the water-seepaging into the soil , use water proof material on entire length

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2. Preparation of base

Choose any one type of base1. W.B.M. base As base material of W.B.M. Road; stone ballast, concrete 10-15cm layer are used. For bonding between concrete slab & W.B.M. used 1:2 cement wash on W.B.M.2. Concrete base On the road used 10cm Cement concrete(1:2:4) or lime concrete(16:32:64)

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3. Form work Material for form work- Wooden sheets, battens, plywood, fibre hard board, steel plates, angles, rope, minerals.

1. before using form work, it should free from all type material like as dust ,cement. 2. To place the concrete in appropriate depth use 2.5-5cm thick and 3mtr long wooden sheeting.

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3. The depth of wooden block must be same as level of slab thick. 4. After 24hrs form work displace next length of road.

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4. Watering of base

If base is dryThan using the sprinkling process on it properly after that placing the concrete.

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5. JOINTS

Wherever it is necessary to provide transverse, Longitudinal joints; there wedge of woods, metals to be fixed on level of concrete. After setting of concrete it should be pull out. If provided the dowel bar in joints, bars should be fit at right position.

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6. Material mix & placing

Mixer is equipment that mix the concrete using distinct amount of cement , concrete, sand and water. Concrete slab should have more than 5-10cm thick cause of drying.Used two type mixer-1. Batch mixer- at site, used for small road construction2. Continuous mixer- Continuous mixer used for large construction . if distance is more from site , mix concrete transported at site within setting time.

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Two methods generally used in placing of concrete-1. Alternate bay method- Placed the concrete on both side of road alternatively like as1,3,5… part at one side and 2,4,6… part other side . 1st side 2nd sideThis method have slow process due to road traffic problems.

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2. Continuous bay method- construct one side of road regularly, if completed some part of first side than construct other side. this method have fast process without no obstruction of traffic

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7. Compaction

Purpose of compaction is that to pull out air from void and make concrete harden. Compaction done by- 1.mechanically surface vibrator 2. manually hand tempers

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8. Finishing of surface

1.Floating- For levelling the surface use floating, scree-ding , power trowel. So that there is no acceptable more than 3mm variation in concrete level surface.2.Belting- For making surface clean used belting process. Belt is nothing but a 15-30cm thick sheets of canvass which have more length than road.

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3. Brooming- Brooming is the process in which we made rough surface parallel to road by brush. It useful in avoiding slip & comfortable travelling on road . the depth of line on road no more than 1.5mm.

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9. Curing

Curing is the name of increasing the hydration process of cement. after setting the concrete , curing process done till 14-28days.

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Some method of curing are-1.Shading concrete works2. Covering with hessian & gunny bags3. Sprinkling of water4.By ponding5. Membrane curing6. Steam curing

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10. Filling joint

After drying road, clean the joints and fill the shelling compound or hot bitumen . also bitumen fill road bank.

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11. Edging

To protect damaging the sides of concrete pavements use kerb of pre mix concrete and carefully finshing done by edging tool.

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12. OPEN TO TRAFFIC

Generally after a month, road should be open to traffic. If used rapid hardening cement it take 7 days to open traffic.

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Thank you