Question

Sheepfoot rollers used for soils compaction are most suitable for
1. Clean coarse grained soil with 4-8% passing 75 micron sieve
2. coarse grained soil with less than 12% passing 75 micron sieve
3. Coarse grained soils with less than 4-8% passing 75 micron passing 
4. Pavement subgrades
5. Fine-grained soils with more than 20% passing 200 micron sieve

Answer 1

Correct Answer - Option 5 : Fine-grained soils with more than 20% passing 200 micron sieve

Explanation:

• In the construction of highway embankments and earth dams, the soil is first dumped in the form of loose fills and then compacted to improve the density and strength of characteristics.
• In the field, the soil is compacted by applying energy through mechanical equipment.
• The choice of equipment will depend on the type of soil and economic consideration. The main compaction equipment along with suitability of soil and nature of the project are summarized below:

Type of equipment	Suitability for soil type	Nature of project
Rammers or Tampers	All soil	In confined areas such as fills behind retaining walls, basement walls, etc.
Sheep foot roller	Clayey soil	Core of earth dam
Smooth wheeled roller	Crushed rocks, gravels, sand	Road construction
Pneumatic tyred roller	Sand, gravels, silts, clayey soil	Base, sub-base and embankment compaction for highways, airfield and earth dam
Vibratory roller	sands	Embankment for oil storage tanks etc.