EFFECT OF MAIZE POD ASH AS STABILISATION OF SUBGRADE SOIL

Abstract

This study focused on effect of Maize Pod Ash (MPA) as stabilisation of subgrade soil and MPA have been found to be promising stabiliser due to its pozzolanic properties. The soil sample was obtained from a borrow pit located at Orita Ara, Ede–Iwo road in Osun State, South Western Nigeria. Maize pod was obtained from maize vendors in Ifon, a rural community in South Western Nigeria. It was dried in the sun to eliminate moisture and was later ground and took to furnace at 650oC temperature to obtain the MPA. Laboratory tests carried out on the soil sample and MPA include X–Ray Fluorescence (XRF), particle size analysis, and the soil stabilisation with 0%, 4%, 8%, 12% and 16% MPA using Atterberg limit, compaction, and California Bearing Ratio (CBR) tests. Chemical analysis using XRF test revealed that MPA is class F pozzolan while the soil was classified as A–2–7(4) according to American Association of State Highway Transportation Official. The compaction test showed that as the percentage of MPA increases, the Maximum Dry Density (MDD) decreases and the Optimum Moisture Content (OMC) increases with the highest MDD (23.2 kN/m3) and lowest OMC (11 %) observed at 8% MPA. It was also observed that 8% MPA have the highest CBR value of 12.94 % compared with the soil sample with 1.40 %. This observation showed that the MPA can upgrade the geotechnical properties of subgrade soil.