Stabilization of lateritic soil with cement – oil palm empty fruit bunch ash blend for California bearing ratio base course requirement

Lateritic soil obtained from a borrow pit at Maya Aladiye, Ijebu – Itokin Road, Ikorodu Local Government Area in Lagos state was classified as an A-6(8) using the American Association of State Highway and Transportation Officials (AASHTO) soil classification system or CL using the Unified Soil Classification System (USCS). It was treated with cement – oil palm empty fruit bunch ash (OPEFBA) blend in stepped concentrations of 0, 2, 4, 6 and 8 % cement as well as 0, 2, 4, 6 and 8 % of OPEFBA, respectively, by weight of dry soil. Index, cation exchange capacity (CEC), compaction and California bearing ratio (CBR) laboratory tests were carried out on the natural and treated soil specimens. Compaction was done using three different effort levels namely, the British Standard light (BSL), West African Standard (WAS) and the British Standard heavy (BSH). The 2-day CBR values (soaked) of the natural soil for the BSL, WAS and BSH compaction efforts increased from 10, 6 and 8 % to 105, 120 and 110 %, respectively, at an optimum 8 % Cement / 2 % OPEFBA treatment. These CBR values met the 80 % requirement for base course materials with a beneficial environmental advantage of utilizing a palm oil mill waste.