EVALUATION OF LIGHTWEIGHT CONCRETE USING CRUSHED COCONUT SHELLS AS PARTIAL REPLACEMENT FOR COARSE AGGREGATE IN RIGID PAVEMENT CONSTRUCTION

This study evaluates lightweight concrete produced by partially replacing conventional coarse aggregate with crushed coconut shells, aiming to develop an eco-friendly and cost-effective solution for rigid pavement construction. The research investigates the feasibility of using coconut shells (a readily available agricultural waste) as a substitute to reduce concrete's overall weight while maintaining adequate structural performance. A comprehensive experimental test was carried out in which concrete mixes were designed with varying levels of crushed coconut shell replacement (e.g., 0%, 10%, 20%, and 30%) for the coarse aggregate replacement. The fresh concrete properties were evaluated using standard slump tests, while the hardened concrete was tested for compressive, flexural, and splitting tensile strengths at 7, 14, and 28 days of curing. The tests were conducted following standard procedures, and the resulting data were tabulated and compared across different replacement percentages. The 7-day compressive strength for the control mix (0% replacement) was 21.09 N/mm², while the 10% replacement mix recorded 20.48 N/mm²; at 28 days, the control mix achieved 30.51 N/mm² compared to 28.27 N/mm² for the 10% replacement. Similarly, flexural strength values at 28 days decreased from 5.75 N/mm² for the control to 5.25 N/mm² at 10% replacement.