Use of Lime and Bagasse Ash in the Modification of Laterite

Abstract

Laterite classified as A-7-6 using AASHTO soil classification, was collected from Shika area of Zaria and modified with up to 4 % lime content by dry weight of soil. Effect of bagasse ash on the lime modified soil was studied with respect to particle size distribution, plasticity characteristics, compaction characteristics and shear strength parameters, using British Standard Light (BSL) compaction energy. Results obtained indicate increase in the particle sizes (i.e curves shifted from the region of fine-grained soil to coarse-grained soil). Improvement in the plasticity of the soil was recorded with decrease in liquid limit and increase in plastic limit. The maximum dry density (MDD) generally decrease when treated with 1 % lime/6 % bagasse ash from 1.79 to 1.76 Mg/m3, while the optimum moisture content (OMC) increased from 16.25 to 18.40 %. The shear strength parameters also generally improved with a decrease in cohesion from 130 to 80 kN/m2, while angle of internal friction increased from 19 to 23° at 1 % lime/6 % bagasse ash contents. On the bases of the compaction and shear strength parameters results, 6 % bagasse ash content can be admixed with 1 % lime for optimal laterite modification.