Stabilizing Potential Of Cement-Fly Ash Mixture On Expansive Clay Soil

Abstract

This study investigated the stabilizing potential of cement-fly ash on expansive clay with a view to discovering a more effective soil stabilization method for road works. It was carried out between July 2003 and March 2004 in Civil Engineering Department, Obafemi Awolowo University, Ile-Ife, Nigeria.The expansive clay soil samples were first subjected to general classification tests where three classes of samples evolved; 12% cement optimal mix, 9% cement plus 3% fly ash optimal mix, and the 0% (unstabilized) natural clay soil sample. The three different classes of samples were then subjected to engineering tests; Maximum Dry Densities (MDD), Optimum Moisture Contents (OMC), California Bearing Ratio (CBR), Unconfined Compression and the Undrained Triaxial. The results showed that the soil sample stabilized with a mixture of 9% cement plus 3% fly ash was better in respect to MDD, OMC, Bearing Capacity and Shearing Resistance, when compared with sample stabilized with 12% cement plus 0% fly ash. This showed that the addition of a certain percentage of fly ash will improve the stabilizing potential of cement on an expansive clay soil.

Keywords: Cement and fly ash stabilization; soil strength; expansive clay; amendment.

Journal of Technology and Education in Nigeria Vol. 12 (2) 2007: pp. 1-8