A.B Fajobi - Department of Civil Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria
O.O Adekanye - Department of Civil Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria

Sawdust is a waste product which has for many years, contributed significantly to the increasing levels of environmental pollution in Nigeria. Sawdust ash (SDA) is a direct product of the total incineration of sawdust. SDA contains a considerable amount of silica (SiO2) needed for pozzolanic stabilization of soil. Lime on the other hand is an additive, which is constantly being used to modify/stabilize soils for civil engineering construction purposes. This paper therefore presents result of a laboratory investigation to establish the suitability of SDA as a complementary additive with lime for stabilizing clayey soils. Clayey soils from a site location in Ile-Ife, Nigeria were treated with different percentages of SDA and lime, individually and in combination, and the Atterberg‟s limits tests and the standard Proctor compaction test were conducted to determine the suitability of SDA as an effective agent of clayey soils. The results of the experiment conducted showed that some mixes of both lime and SDA reduced the plasticity index of the clayey soil considerably. The optimal percentage was 6% lime and 10% SDA in combination which reduced the plasticity index and increased the maximum dry density of the soil. It can be concluded that this optimum mix of lime-SDA combination could be used for construction work in which the reduction of swelling and shrinkage of clayey soils is of prior importance.

Lime, Sawdust Ash, Stabilisation, Plasticity, Compaction