Stabilization of Highway Expansive Soils with High Loss on Ignition Content Kiln Dust
This study was carried out to evaluate the effect of high loss on ignition content cement kiln dust on the stabilization of highway expansive soils. Laboratory tests were performed on the natural and stabilized soil samples in accordance with BS 1377 (1990) and BS 1924 (1990), respectively. The preliminary investigation carried out on the expansive soil (also known as black cotton soil) found in Deba, Gombe State, Nigeria shows that it falls under Silt-Clay material of Group A-7-6 (16) using AASHTO classification and inorganic clay material CL according to Unified Soil Classification System (USCS). The maximum dry density (MDD) for British Standard Light (BSL) and British Standard Heavy (BSH) compactive efforts increased to peak values of 1.66 and 1.91 Mg/m3 at 6% and 4% cement kiln dust (CKD) contents respectively. The MDD for West African Standard (WAS) compactive effort increased with higher CKD content. The Optimum Moisture Content (OMC) for BSL and BSH compactive efforts increased up to 6% CKD content then decreased with higher CKD content. For the WAS compactive effort, the OMC generally decreased with higher CKD content. The unsoaked California bearing ratio (CBR) values of 3, 5 and 7% for the natural soil compacted with BSL, WAS and BSH compactive efforts, respectively, increased to 7, 10 and 19% at 10% CKD content. The 24 hour soaked CBR values of the natural soil of 3% for BSL, 3% for WAS and 5% for BSH compactive energies, respectively increased to their peak values of 5%, 6% and 8% respectively at 10% CKD content.