doi:10.3850/GI175

ABSTRACT

Expansive clay sub-grades suffer damage due to alternate swelling and shrinkage caused by seasonal moisture changes. Stabilization by mixing additives is time-consuming and bristles with the possibility of non-uniformity in mixing. An alternative in the form of lime- or cement-stabilized fly ash cushion over the expansive sub-grade is proposed. The cushion has been found to minimize heave of the sub-grade. In addition, the cushioning material, which has a high CBR value, serves as sub-base for the pavement. The reduction in heave as well as the increase in CBR was proportional to the thickness of the cushion. Cement-stabilized cushions were more effective than lime- stabilized cushions.

Keywords: Expansive clays; sub-grades; swelling; shrinkage; stabilization; cushions.

© 2010 by Geotechnical Society of Singapore (GeoSS)