Geotechnical properties of clayey soil stabilized with cement-sawdust ash for highway construction

Abstract

The study was conducted to investigate the different effects of cement-sawdust ash and cement on a clayey soil sampled from Mandate Lodge, Landmark University, Omu-Aran, Nigeria. The binder mix of cementsawdust ash (CSDA) was mixed in a ratio of 1:1. The CSDA and cement were added to the soil samples at varying percentages of 1.5, 3.0, 4.0, and 7.0% by weight of the soil. Atterberg limits and strength tests (unconfined compressive strength (UCS) and direct shear (DS) test) were performed on the samples to determine the suitability of the stabilized soil as a construction material in highway pavement.Atterberg limit test result showed that the addition of 7% cement decreased the liquid limit from 58% to 42% and plasticity index from 18% to 3%, while the addition of 7% CSDA decreased the liquid limit from 58% to 48% and plasticity index from 18% to 4%. The atterberg limit test results also showed that the stabilized clayey soil samples met the requirements of the Nigerian General Specifications of maximum plasticity index (PI) of 30% and liquid limit (LL) of a maximum of 50% when used as a subgrade material in highway construction. The strength test result showed that the strength values of the samples increased with binder addition and met with the requirement for use as a subgrade material in highway construction.

Keywords: Cement, Saw dust, strength test subgrade material, highway construction