Compaction is the process of removing air voids of soil in order it increase its dry unit weight. Mechanical effort is required in order to compact soils due to which rollers are used. Different rollers have different compaction mechanism and are suitable for different types of soils.

In the end summary is presented in order to guide which type of roller is suitable for a particular soil type.

Smooth-wheel roller (drum)

 

roller

  • 100% coverage under the wheel
  • Contact pressure up to 380 kPa
  • Can be used on all soil types except for rocky soils.
  • Compactive effort: static weight
  • Weaker aggregates crush
  • The most common use of large smooth wheel rollers is for proof-rolling subgrades and compacting asphalt pavement.

Pneumatic (or rubber-tired)

rubber

  • 80% coverage under the wheel
  • Contact pressure up to 700 kPa
  • Can be used for both granular and fine-grained soils.
  • Compactive effort: static weight and kneading.
  • Can be used for highway fills or earth dam construction

Sheep Foot Rollers

 

sheepfoot_roller_compactor_by_northtechmodels-d5yjtpl

  • Has many round or rectangular shaped protrusions or “feet” attached to a steel drum
  • 8% ~ 12 % coverage
  • Contact pressure is from 1400 to 7000 kPa
  • It is best suited for clay soils.
  • Compactive effort: static weight and kneading.

Tamping Foot Roller

 

sheep

  • About 40% coverage
  • Contact pressure is from 1400 to 8400 kPa
  • It is best for compacting fine-grained soils (silt and clay).
  • Compactive effort:  static weight and kneading

Mesh (Grid Pattern) Roller

 

mesh

  • 50% coverage
  • Contact pressure is from 1400 to 6200 kPa
  • It is ideally suited for compacting rocky soils, gravels, and sands. With high towing speed, the material is vibrated, crushed, and impacted.
  • Compactive effort: static weight and vibration

Vibrating Drum On Smooth-Wheel Roller

 

smooth

  • Vertical vibrator attached to smooth wheel rollers.
  • The best explanation of why roller vibration causes densification of granular soils is that particle rearrangement occurs due to cyclic deformation of the soil produced by the oscillations of the roller.
  • Compactive effort: static weight and vibration.
  • Suitable for granular soils

Rollers-Summary

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Civil Engineer MSc from National University Of Sciences And Technology.

1 COMMENT

  1. The most suitable soils for these roller type are well graded sand, gravel, crushed rock, asphalt etc. where crushing is required. These are used on soils which does not require great pressure for compaction. These rollers are generally used for finishing the upper surface of the soil. These roller are not used for compaction of uniform sands.

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