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Construction Road Transportation

Equipment used in Road Construction

Road construction technology is that branch of Highway Engineering which deals withal all kinds of activities and technology for changing the preexisting ground surface to the designed shape, slope and to provide all necessary facilities for smooth, safe, and efficient traffic operation. It also includes the reconstruction of existing roads.

Different types of tools, equipment, and plants are used for the construction of roads. Those civil engineering students who are planning to work on the road in the future should have knowledge about Tools, Equipment, and Plants used in Road construction.

Equipment generally refers to a set of tools used for a single purpose.

Different types of equipments used for different purposes of work in road construction.

  1. Rollers: For the compaction of soil Roller is used in road construction. It is used to compact the base, sub-base, and surface course. There are different types of rollers with having different specific functions. 
  2. Grader: A grader is used for grading the road. It is used for thin layer excavation in the longer area. It contains a grading blade that can be rotated so that collected materials can be pushed horizontally.
  3. Bitumen Boiler: To change the solid bitumen to a liquid or semi-solid state bitumen boiler is used. On the top of the bailer, a manhole is provided for inspection and bitumen charging. Earlier boilers fired with wood or coal, but modern boiler uses diesel fuel burners.
  4. Bitumen Distributor: A tank mounted on a truck used to carry liquid state bitumen. Heated bitumen in the form of liquid is fed to bitumen distributors. To maintain the temperature of bitumen it is equipped with burners. A bitumen spraying is attached to the tank which sprays bitumen in fan shape through the nozzle. spraying is done under pressure.
  5. Aggregate Spreader: In dump trucks, a spreading is fixed on its tali which spread aggregate uniformly throughout the road section where bitumen is sprayed. Nowadays latest aggregate spreaders contain both the bitumen as well as an aggregate spreader. From which first Bitumen spreads and then followed by aggregate spreaders. So combined work can be done in the latest technology spreaders.

These are the main equipment used in the construction of the road.

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Road Transportation

Bitumen – Properties and Uses

Bitumen is known as petroleum in the fluid state, mineral tar in the semifluid state and asphalt in the solid-state. It is a solid or semi-solid black, sticky, ductile substance, obtained as a crucial byproduct from the distillation of crude fossil oil.

It may even be outlined as that portion of fossil oil asphalt and tar product, which is able to dissolve in carbon disulphide. Bitumen implies a bunch of hydrocarbons typically mixed with some organic matter.

Properties of bitumen

  1. It’s characteristically solid or semi-solid, black and sticky.
  2. It melts or softens on the application of warmth.
  3. Its specific gravity is 1.09.
  4. It is completely soluble in carbon disulphide.
  5. it’s a binder all told kinds of asphalt.
  6. It possesses nice chemical stability but is affected by oil.
  7. it’s low permittivity and high insulation resistance

Uses of bitumen

It is used as a damp proof course in walls and under-basements and inlining tanks, swimming pools, urinals, etc. Since it forms a smart growth joint so, it’s used for filling up the joints in leaky roofs.

Categories
Construction Road Transportation

Road Maintenance and its types.

The process of preserving and keeping the conditions of the highway serviceable and as best as practicable normally as far as possible is known as highway maintenance or road maintenance. The cost of road maintenance depends upon the road location, design of the road, the quality of construction and the quality of maintenance.

A) Roadside Maintenance

The maintenance activity on the structures and surface above as well as below the road having a direct or indirect influence on the road falls under roadside maintenance. It includes protection walls, retaining walls, cut slopes, fill slopes, unstable natural slopes, river protection activities and bio-engineering works.

B) Road Maintenance

All the maintenance activities are related to roadway and all the structures within and immediately adjacent to the roadway such as ditches, culverts, causeways, bridges, etc. 

Road maintenance is divided into the following subcategories:

A) ROUTINE MAINTENANCE: The maintenance activities that are done regularly or daily is called routine maintenance. The activities carried out under the routine maintenance are:-

  • Grass and bushes cutting
  • Grading and reshaping of unpaved shoulders
  • Road sign maintenance
  • Clearing and cleaning of ditches culverts etc.

B) RECURRENT MAINTENANCE: The maintenance activities that are done more and more or less regular intervals of six months to two years frequency is called recurrent maintenance. Maintenance’s under recurrent maintenances are

  • Sealing off cracks in highway and roads
  • Patching of potholes
  • Repairing depressions, holes and ruts
  • Repairing road edges

C) PERIODIC MAINTENANCE: The maintenance activities that are carried out at an interval of 5 to 7 years are periodic maintenance. The main activities under periodic maintenance are resealing and resurfacing.

D) EMERGENCY MAINTENANCE: It is divided into two subcategories:

i) Urgent emergency maintenance: It refers to the reopening of roads under any cost. The following activities fall under urgent emergency maintenance.

  1. Removal of debris.
  2. Obstacles removing
  3. Diversion works

ii) Reinstatement of roads: This activity is done generally when the rainy season is over by reconstruction or repair of pavement, structures, and the drainage as per the requirement of highway geometry.         

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Construction Road Transportation

Water bound macadam road construction procedure

The water-bound macadam construction named after john macadam. In the macadam road construction, the crushed or broken aggregates are bound together by using the rolling procedure.

Binding can be achieved by the use of stone dust as a filler in the presence of water.

The WBM roads are divided into the following types according to the materials used for construction:

  1. WBM roads with gravel including crushed gravel
  2. WBM roads with hard broken stones
  3. WBM roads with soft broken stone and brick residue

Procedure for macadam road construction

a) The thickness of WBM should be from 8cm to 30 cm with each layer of compaction from 7.5cm to 15 cm.

b) The camber provided should be a minimum of 1 in 36 to a maximum of 1 in 48.

c) Materials:

  1. Coarse aggregates:
    1. the crushed and broken stones should be hard,
    2. durable,
    3. strong,
    4. and free from excess of flaky and elongation.

The requirements of coarse aggregates are:

  • Aggregate impact value (AIV) = 30%
  • Los angles abrasion value (LAA) = 40%
  • Flakiness index (FI) = 15%

2. Screening materials of grade A with passing through screening size of 12.5 mm and grade B with a size of screening 10 mm

3. Filler materials of plasticity index (PI) up to 9 shall be used

d) Equipment used

  1. Aggregate spreader
  2. Water tankers
  3. Grader
  4. Compaction equipment (road roller)

e) Construction procedure

  1. 20% of extra broken stones should be provided than estimated.
  2. The subgrade surface is prepared
  3. Pavement construction is carried out by lateral confinement and spreading of coarse aggregates
  4. Dry rolling is done by roller with a load of 6 to 10 tons
  5. Application of screening materials
  6. Wet rolling is carried out to fil about 50% of remaining voids
  7. Filer materials with plasticity index up to 9 are applied in two successive thin layers
  8. Finishing off is done by 6 mm thick sand or earth spreading, sprinkled with water and rolled.
  9. Shoulders are prepared
  10. The WBM is opened for traffic after a few days of construction.

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