Experimental Study on Strength Characteristics of Fly Ash and Rice Husk Ash added Clay Soil

Abstract. Clay soil is usually stiff in dry state, but in wet state, it loses its stiffness and becomes softer. Various types of clay minerals have unique characteristics of low bearing capacity and certain compressibility. Especially Montmorillonite clay mineral exhibits more degree of swelling and shrinkage and loss of strength when moisture added. According to recent research, rice husk ash is a potential improving material based on its pozzolanic activity. In this study, to improve the engineering properties of expansive clay the admixture such as fly ash and rice husk ash will be added in different percentages as 5, 10, 15 and 20. For the laboratory test that includes atterberg’s limits test, standard proctor compaction test and unconfined compression test were conducted on locally collected expansive soil with various percentages of these two stabilizers in order to examine their influences. The maximum values of Unconfined Compressive Strength were obtained corresponding to 15% Rice Husk Ash and 20% Fly ash.