The objective of this paper is to upgrade expansive soil as a construction material using rice husk ash (RHA) and flyash, which are waste materials. Remolded expansive clay was blended with RHA and flyash and strength tests were conducted. The potential of RHA-flyash 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 106% and 50% respectively when the flyash content was increased from 0 to 25%. When the RHA content was increased from 0 to 12%, Unconfined Compressive Stress increased by 97% while CBR improved by 47%. Therefore, an RHA content of 12% and a flyash content of 25% are recommended for strengthening the expansive subgrade soil. A flyash content of 15% is recommended for blending into RHA for forming a swell reduction layer because of its satisfactory performance in the laboratory tests.
Behak, L. (2017). Soil Stabilization with Rice Husk Ash. In Rice - Technology and Production. InTech. https://doi.org/10.5772/66311