Dept. of Civil and Environmental Engg., Temple University, 1947 N. 12th Street, Philadelphia, PA 19122, USA.
The objective of this paper is to stabilize expansive soil using rice husk ash (RHA), a waste material and lime. Remolded expansive clay was blended with RHA and lime and strength tests were conducted. The potential of RHA-lime blend as a swell reduction layer between the footing of a foundation and subgrade was studied. In order to examine the importance of the study, a cost comparison was made for the preparation of the sub-base of a highway project with and without the admixture stabilizations.
Stress strain behavior of unconfined compressive strength showed that failure stress and strains increased by 100% and 29% respectively when the lime content was increased from 0 to 4%. When the RHA content was increased from 0 to 12.5%, Unconfined Compressive Stress increased by 127% while CBR improved by 100%.
Therefore, an RHA content of 12.5% and a lime content of 4% are recommended for strengthening the expansive subgrade soil. A lime content of 5% is recommended for blending into RHA for forming a swell reduction layer because of its satisfactory performance in the laboratory tests.
Rice Husk Ash, Lime, Expansive Clay, UCS, CBR and Swell Tests
