COMPACTION TEST(Method Based On BS1377 : Part 4 1990)

Scope :

Compaction tests furnish the following basis for soil data:1. The relationship between dry density and moisture content for a given degree of

compaction effort.2. The moisture content for the most efficient compaction that is, at which the maximum

dry density is achieved under that compaction effort.3. The value of the maximum dry density so achieved.

Objectives of proper compaction:

Soils may be as fill for many purposes, the most usual being :1. The refill an excavation, or a void adjacent to a structure, such as behind a retaining

wall.2. To provide made-up ground to support a structure.3. As a sub-grade, sub-base and crusher run for a road, railway or airfield runway.4. As a structure in itself, such as an embankment or earth dam, including reinforced

earth.

Type of test :

BS heavy compaction test (4.5 kg rammer method BS 1377 : 1975. Test 13 / 1990 Part 4)

This test is still often refered to as the modified proctor test and as the moisture-density relationship test. It is suitable for soils containing particles no larger than 20mm. The detailed procedure depends on whether or not the particles are susceptible to crushing during compaction. It gives the dry density-moisture content relationship for a soil compaction in five layers in the same mould, using 27 blows per layer with a 4.5kg rammer falling 450mm. The total compactive energy applied is 4.5 times greater than in the ordinary test. From the density-moisture curve the optimum moisture content and the maximum dry density, for this heavier degree of compaction can be determined.