Depending on the requirement of the project and the soil to be compacted, different types of rollers are used for compaction work. There are different types of rollers used for compaction:

  1. cylindrical rollers
  2. sheep’s foot rollers
  3. Pneumatic Tire Rollers
  4. Smooth Wheeled Rollers
  5. vibratory rollers
  6. grid rollers

The following types of road rollers are commonly used.

1. cylindrical roller

  • This is a light roller of iron, concrete or stone; drawn by hand or bull. The size varies, but it is usually about 1 meter in diameter. and about 1.5 meters long.
  • This ground pressure generated by this type of roller is approximately 7kg/cm2,

2. sheep’s foot roller

sheep's foot roller
sheep’s foot roller
  • As the name indicates, this type of roller consists of a drum consisting of several round or rectangular shaped protrusions or “Feet” on it. These rollers are also called tamping rollers,
  • There are a variety of drums available with different diameters and widths and different lengths and sizes of feet. The most common type consists of two drums 1.22 m wide and 1.06 in either taper-foot or club-foot rollers depending on the size of the foot.
  • The area of ​​each protrusion may differ from 30 to 80 cm2,
  • coverage area is approx 8 to 12%.
  • The thickness of the compaction layer is kept approximately 5 cm more than the length of each foot,
  • This type of roller is mostly used for compaction of compacted soils such as heavy clay and silty soils. Not effective with sandy soils.
  • The weight of the drum can be increased by filling the drum with water or moist sand.
  • The factors that control the amount of soil compaction are as follows:
    • Gross Weight of Roller
    • area of ​​each foot
    • number of feet or lugs in contact with the ground
    • Total number of feet per drum
    • Maximum pressure is exerted on the soil when one foot is vertical.
  • Soil should be consolidated when the impression by the protruding teeth is no more than 12 mm deep or when the surface has been rolled 16 to 20 times,
  • 10 to 20 pass Generally it is required to give full coverage.
  • The density of the consolidated soil is about 1.48 kg/cm. should be3, The top layer will need to be finished with a smooth wheel roller.
  • The pressure on the feet can be increased by filling the drum with wet sand or some other material, which may be 4 to 7 kg/cm.2 For light rollers and 25 to 70 kg/cm. So far2 For giant rollers.

3. Pneumatic Tire Rollers

Pneumatic Tire Roller
Pneumatic Tire Roller
  • This type of roller consists of a heavy wagon with several rows of four to six closely spaced tyres. It is also called rubber tiered roller.
  • This provided uniform pressure across the entire width.
  • The 2 factors that control the amount of compaction are as follows:
    • tire pressure
    • area of ​​contact
  • Tire pressure approx. can be up to 7kg/cm2
  • coverage area is approx 80%,
  • The aggregate weight of the roller is about 6 to 10 tonnes which can be increased to 25 tonnes by ballasting by steel section or other means.
  • The maximum density can be obtained by 8 pass Why roller? The optimum speed of the roller is between 6 to 24 km/h,
  • Used for compacting layers of cold lay bituminous pavement, soft base course material or loose soil. These rollers are also suitable for compacting finely graded sand, and the moisture content in fine-grained adhesive soils approaches their plastic limits, although compaction is not as high as with a smooth wheel roller. .
  • They are especially efficient when used with a sheep’s foot roller or for dismantling embankments on loose sandy soils.

4. Smooth Wheeled Roller

tandem roller
tandem roller
  • This type of roller consists of a large steel drum at the front and one or two wheels or drums at the rear end.
  • Depending on the number of rear wheels, it can be of the following two types:
  1. Tandem rollers (one wheel back and one wheel forward)
  2. Three wheel rollers (with two wheels on the back and one in the front)
  • tandem roller weight Changes 2 to 8 tons and that two wheel roller Changes 8 to 10 tons

    three wheel roller
    three wheel roller

  • This ground coverage Smooth wheeled roller is provided by 100%,
  • The weight of the roller can be increased by filling the space inside the drum with water or wet sand. it is called loose rock,
  • ground pressure Mounted by tandem rollers approx. Is 10 to 17 kg/cm2,
  • The performance of smooth wheel roller depends on the load per cm width and diameter of the roll.
  • The speed and number of passes of a smooth wheel roller depend on the type of soil and the requirements of the project. The optimum working speed has been found to be 3 to 6 km/h and about 8 passes are enough to compress a 20 cm layer,
  • Smooth wheel rollers are best suited for reinforcing stone sawing, gravel, sand, hard core, ballast and surface dressing. Not suitable for fortifying embankments and soft subgrades, but better suited than any other plant on loaming silty and sandy soils and with fewer passes. It will compress more easily when the moisture content is slightly higher than optimal.
  • The two types (ie steam and diesel) are very similar, the difference is mainly in the power unit. Adjustable weight devices are available that can be fitted on wheels to vary the rolling pressure to suit different cohesion needs. When doing heavy work, the sliding load should always be behind the roller. The sliding load should never be moved when the roller is on the slope.
  • Steam road roller can withstand heavy wear and tear and is much simpler to operate than diesel roller but it takes more than an hour to start and cannot be stopped temporarily, Whereas the diesel type can be started and stopped in no time. Minutes and does not consume fuel when temporarily standing idle on the job. Steam road rollers are getting old now. Diesel rollers are cheap in running cost.
  • Some rollers are built with its prime movers or engine as a separate unit which is a tractor, and is mounted on the roller, and this has its own advantages.
  • To scrape off the mud during rolling and keep the wheels clean, scrapers are provided on all wheels in an adjustable position covering the entire width of the roll, with a water sprinkler system.
  • The maximum grade a road roller can climb is 1 in 5.

5. vibratory rollers

vibratory roller
vibratory roller
  • This type of roller consists of one or two smooth surface steel wheels 0.9 m to 1.5 m in diameter and 1.2 m to 1.8 m wide.
  • Self propelled vibratory rollers are now available for weighing 4 to 6 tons,
  • Vibrations are produced by the rotation of an eccentric shaft inside.
  • A vibratory roller is used to compress the granular base courses. It is sometimes used for asphalt concrete work.

6. grid rollers

grid roller
grid roller
  • These rollers have a cylindrical heavy steel surface with a network of steel bars forming a grid with square holes and may be ballasted with concrete blocks.
  • They are usually towing units and can operate at speeds between 5 and 24 km/h,
  • Specific weight varies between 5 ton net And 15 ton ballast,
  • grid rollers provide high contact pressure But little kneading action and most coarse grained soils are suitable for compacting.

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.