Cement Kiln Dust: Locust Bean Waste Ash Blend Stabilization of Tropical Black Clay for Road Construction

Abstract

This paper presents the result of a laboratory study carried out on an expansive tropical black clay (also known as black cotton soil because the cotton plant thrives well on it) treated with locust bean waste ash (LBWA) using cement kiln dust (CKD) as an activator. Compaction was carried out using British Standard light energy. Results of index properties, compaction characteristics (maximum dry density, MDD and optimum moisture content, OMC) and strength characteristics (California bearing ratio, CBR and unconfined compressive strength, UCS) of black cotton soil treated with a maximum 8% CKD/10% LBWA blend by dry weight of soil is presented. Test results show that the strength properties of the treated soil generally increased with higher additive contents and peak values were recorded at 6% CKD/6% LBWA content. Based on strength criterion, an optimal 6% CKD/6% LBWA is recommended for treatment of black cotton soil for use as sub base material in road construction.