Soil stabilization varies with engineering characteristics of any soil, stabilizing admixtures alters the pore structure which in turns alters the hydraulic characteristics of the soil. Silica based materials and waste ashes are widely used as stabilizing agents for swelling soil such as black cotton soil. Boiler feed ash (Precipitated silica (PS)) is used as stabilizing agents in this study and the hydraulic property variations with various proportions is studied. Up to 30% addition, the hydraulic property decreased and the increasing proportions increased the hydraulic conductivity. Thus, in this study, the optimal use of feed ash is suggested to be 10 to 30% by weight for Black cotton soil. © 2015 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.