Stabilization Potential of Openly Burnt Coconut Waste AshesonA-7-5 Soi

Soil materials are a vital element in all civil engineering designs hence the first step in any geotechnical engineering project is to identify and describe the soil condition if not suitable, disposal or stabilization of the soil should be carried out . In lieu of these, this research was carried out to study the effects of coconut waste ash (CWA) derived from open uncontrolled burning on lime stabilized A-7-5 soil for road construction. Natural soil was collected from a borrow pit location in Ikere Ekiti, Nigeria. Preliminary tests such as natural moisture content, specific gravity, particle size distribution and Atterberg limits were carried out on the soil for classification and identification purposes according to BS 1377 part 2 (1990). Strength tests such as compaction, California bearing ratio and unconfined bearing ratio were also carried out on the natural soil and stabilized soil according to BS 1924 (1990). The soil sample was mixed with lime in the proportions of 2, 4, 6, 8 and 10%, and were each subjected to Atterberg limits tests and strengths to determine the optimum quantity of lime for stabilizing soil. The plastic index varied from 13.93 – 9.33% for lime stabilized soil with optimum values obtained at 8%. Plastic index decreased as the percentages of lime and CWA increased for CWA of ratio 1:1, 3:2 and 2:3 i.e. PI varied from 8.63 to 11.91%. Notable improvements were also observed in the MDD, UCS, OMC and CBR values of stabilized soil therefore coconut waste ash can be used to stabilize A-7-5 soil.