The effects of wetting and drying cycles on the dry density of compacted cohesive soils

The objective of this study was to determine the factors that control the change in dry density of a soil when subjected to cyclic wetting and drying. The Gasconade Clay, a cohesive soil of low plasticity, was used in this study. Three samples for each of four different dry densities, were tested in this study. For each density, the samples were tested at two different confining pressures. The amount of accumulative volume change for each cycle was recorded in all cases. Samples tested dry of OMC experienced a greater amount of shrinkage at a confining pressure of 8 psi rather than 3 psi. As the dry density of the soil increased the amount of volume change decreased. For the samples compacted wet of OMC, the amount of shrinkage increased as the dry density decreased. The samples tested at a confining pressure of 8 psi experienced less shrinkage than the samples tested at 3 psi. It was found that for each dry density and confining pressure, the amount of volume change experienced was different. It was determined that the final dry density of a soil, after being subjected to cyclic wetting and drying, depends upon the initial dry density and water content --Abstract, page iii