Potentials of Processed Palm Kernel Shell Ash (Local Stabilizer) and Model Prediction of CBR and UCS Values of Ntak Clayey Soils in Akwa Ibom State, Nigeria

Abstract

It is very essential to improve on the study of stabilization, as we investigate the potential of Processed Palm Kernel Shell Ash (PPKSA) as a Local stabilizer in stabilizing clay soil. The ever-increasing cost of construction materials in Nigeria and other developing countries has created the need for improved research into locally and readily available materials and also on how to convert these local materials such as Palm Kernel Shell Ash for use in construction and soil improvement. To achieve this; soil samples were collected from Ntak – Uyo, Akwa Ibom State classified as an A-2-5 soil on AASHTO and CL on UNIFIED SYSTEM of classification, were sieved and passed through sieve No. 36. It was then stabilized with (2-7%) Processed Palm Kernel Shell Ash (PPKSA) by weight of the dry soil. The investigation includes evaluation of the engineering and geotechnical properties of the soil. The results obtained shows that the increase in PPKSA content at 4.5% increase the Optimum Moisture Content (OMC) by 16.74%, Maximum Dry Density (MDD) by 1.89 gm/cm3, Unconfined Compressive Strength (UCS) by 433.12 kN/m2, California Bearing Ratio (CBR) by 55% for unsoak and 36% for soak while there was a significant reduction in the value of Liquid Limit (LL) by 30.92% and Plasticity Index (PI) by 10%. The predictive models were developed, and these models showed a good correlation with experimental results in the control tests as they possess a reasonable significant difference and a strong relationship between the measured and predicted values. The study concluded that PPKSA can be used to improve the properties of soil for construction purposes and 4.5% PPKSA content was observed to yield maximum improvement for OMC, MDD, CBR and UCS values.