Effect of Lime Treatment on Expansive Soils at High Initial Water Content

Abstract

Deep soil mixing is widely used technique for stabilizing thick deposits of soft clays. A laboratory trail was carried out to extend its application for stabilizing the expansive soils at high water content. Lime was used as a principal stabilizing agent and in addition to that pond ash was mixed at proportions of 10, 20 and 30% based on dry weight basis. The degree of shrinkage, swell and unconfined compressive strength characteristics were studied to evaluate the efficacy of the treatment method. The experimental findings show that the addition of 4–8% lime increased the unconfined compressive strength from 35 to 650 kPa at different initial water contents of 0.8–1.2 times the liquid limit (w_L). The swell potential of the stabilized soil reduced to zero percentage on first wetting because of its high initial water content and pozzolanic reactions, but it showed a significant swell during second wetting which varied from 4.4 to 6.4% at 1.0 w_L. The strength of lime-pond ash admixed soil shows a significant increment at 10% pond ash and further addition resulted in reduction in the strength characteristics. However, during the second wetting, the swell increased for 10 and 20% pond ash admixed soil and then it deceases for 30% pond ash admixed soil.