THE PRODUCTION OF LIGHTWEIGHT CONCRETE USING COCONUT SHELL

This study investigates the production of lightweight concrete using coconut shells as partial replacements for conventional coarse aggregates, aiming to assess strength characteristics, feasibility, and develop effective mix designs. The particle size distribution analysis indicated that the highest percentage of aggregates fell within the 14-20 mm range, ensuring proper grading. Moisture content was found to be 2.66% for fine aggregates and 1.34% for coarse aggregates, while specific gravities were 2.64 for fine, 2.77 for coarse, and 1.35 for coconut shells. The coconut shell aggregate exhibited impact values between 1.31 and 1.34 and a crushing value of 1.159%, well below the maximum of 30%, confirming its suitability for lightweight concrete. However, workability decreased with increased coconut shell replacement; at a water-cement ratio of 0.5 and a 1:2:4 mix, the control mix achieved a compressive strength of 17.26 N/mm² at 7 days, dropping to 12.67 N/mm² with 12% replacement. After 28 days, the control mix reached 22.44 N/mm², with lower strengths observed for higher replacements. While coconut shells effectively reduce density, they also lead to significant reductions in compressive strength, highlighting the need for further research and mix design adjustments for optimal application in concrete.