Usually, the costs of conventional additives (portland cement, lime, etc) for stabilizing roads are all on the high side. However, plantain peels ash (PPA) is an agricultural waste obtained from plantain. The lateritic soil sample used in this research was obtained from a borrow pit, laboratory tested and classified as A-7-5(3) [AASHTO classification]. It was then stabilized with varying percentages of PPA (2, 4, 6, 8 and 10%). Another set of soil samples was later stabilized with constant 5% ordinary portland cement (OPC) plus varying percentages of PPA (2, 4, 6, 8 and 10%). The maximum dry density (MDD), un-soaked and soaked CBR increased from 1.78 to 1.83%, 30 to 91% and 11 to 119.7%, respectively with PPA addition only; but interestingly, decreased from 1.78 to 1.75%, 265.9 to 148.5%, and 400 to 318% respectively with 5% OPC plus PPA. The optimum moisture content (OMC) increased from 16.93 to 18.52% with 5% OPC plus PPA; also, the UCS values increased from 78 to 170 kN/m2 on addition of PPA only and increased from 66 to 190 kN/m2 with addition of 5% OPC plus PPA. Conversely, as the MDD witnessed increment, the OMC witnessed decrement from 16.93 to 15.01% with PPA addition only. From these results, it can thus be concluded that PPA is a good stabilizer for lateritic soil, even without the addition of ordinary portland cement.

Keywords: Plantain peel ash, stabilization, ordinary portland cement, California bearing ratio, unconfined compressive strength.