DRY DENSITY VARIATION OF COHESIVE SOILS WITH THEIR PLASTICITY CHARACTERISTICS

The increase in the dry density of soil produced by compaction depends mainly upon the moisture content of the soil, the amount of compaction applied and the type of soil. Plasticity is a major characteristics of cohesive soil which is useful in evaluating the behaviour of soil intended for raking a fill. A laboratory investigation was carried out to study the moisture content-dry density relationship and plasticity characteristics of cohesive soils and corelate the various parameters. Six different type of soils collected from different areas of Peshawar were studied. Relationships of maximum dry density and optimum moisture content of soils with their liquid limit, plastic limit and plasticity index have been developed and presented in the form of curves. The investigation has shown that the maximum dry density decreases but the optimum moisture content increases with increase in the liquid limit, plastic limit and plasticity index of cohesive soils.