Stabilization of Soil with Cassava Peel Ash – Lime Admixture

Abstract

This project examined the geotechnical properties of lateritic soils modified with Cassava Peel Ash-Lime admixture with a view to obtaining a cheaper and effective road stabilizer. After collecting samples 1, 2 and 3 from three borrow pits meant for road construction works, preliminary tests was performed on the samples for identification and classification purposes, followed by the consistency limit tests. Engineering property tests (compaction, California bearing ratio (CBR) and Unconfined Compressive Strength) was performed on both at the stabilized and unstabilized states with the addition of 2, 4, 6 and 8% Cassava Peel ash and 1%, 2% and 3% lime contents. The results showed that the soil samples were well graded sand with fair to poor rating as subgrade material for pavement construction. However, the engineering properties of the samples were further improved with the addition of Cassava Peel Ash-Lime Admixture. This caused reductions in the PI of samples 1 from 9% to 1% and 6%. Optimum values of maximum dry densities (MDD) and shear strengths were obtained at 4% for sample 1 and 3, 6% at sample 2 CPA+Lime stabilization. MDD increased to 1.680, 1.680 and 1.920 Mg/m³ respectively in samples A, B and C. We therefore concluded that Cassava Peel Ash-Lime Admixture has a good potential for improving the geotechnical properties of lateritic soils.

Keywords: Cassava peel ash, Compaction, California bearing ratio, unconfined Compressive Strength