MODELING AND PERFORMANCE EVALUATION OF CBA, CCA, FA, POCP, RHA, POFA ADDITIVES ON THE GEOTECHNICAL PROPERTIES OF LATERITIC SOIL FOR SUSTAINABLE ROAD CONSTRUCTION

Lateritic soils are widely used in road construction across tropical regions due to their abundance, yet their natural geotechnical properties often fall below the requirements for sustainable pavement performance. In order to enhance their strength, durability, and long-term serviceability, chemical stabilization with industrial and agricultural waste additives has emerged as a viable approach, both technically and environmentally. This study evaluates the performance of six supplementary materials which includes Corn cob Ash (CCA), Coal bottom Ash (CBA), Fly Ash (FA), Palm Oil Clinker Powder (POCP), Rice Husk Ash (RHA), and Palm Oil Fuel Ash (POFA), as potential stabilizers for lateritic soil in road construction. The objective was: i) to assess the impact of different pozzolanic materials (CBA, CCA, FA, POCP, RHA, and POFA); ii.) to evaluate the strength and durability performance of stabilized lateritic soil under varying proportions of pozzolanic additives for potential application in road construction. on the strength and compressive properties of lateritic soil; and iii.) to determine the optimum blend of pozzolanic additives by evaluating their CEC behavior in order to achieve improved long-term stability of roadworks materials. Laboratory tests were conducted at varying additive replacement levels to determine the optimum percentage for improved soil performance. Findings revealed that all additives enhanced soil properties to varying degrees, with FA and RHA showing the most significant improvement in strength and bearing capacity, while POFA and CCA contributed to better durability and reduced plasticity. POCP provided moderate but consistent enhancement in compaction and UCS, making it effective in blended applications. The combined use of certain additives demonstrated synergistic effects, particularly FA-RHA and POFA-CCA mixtures, which achieved higher CBR values suitable for sub-base and base course layers in road pavement. The study recommends the utilization of FA and RHA as primary stabilizers for lateritic soil in heavily trafficked roads, while CCA, POCP, and POFA are more suitable for secondary or blended applications where cost and availability are key considerations. Overall, the adoption of these industrial and agro-waste materials in soil stabilization not only enhances geotechnical performance but also promotes sustainable waste management and reduces reliance on conventional cement and lime stabilizers.