USE OF COCONUT SHELL AS COARSE AGGREGATE IN LIGHTWEIGHT CONCRETE

USE OF COCONUT SHELL AS COARSE AGGREGATE IN LIGHTWEIGHT CONCRETE

Abstract:

This research work reports the investigation carried out to determine the use of coconut shell as an aggregate in light weight concrete. Concrete samples were produced with different mix ratios, to determine the best and economic proportions that will give acceptable compressive strengths. Coconut shell aggregate exhibits low impact, crushing, and abrasion values of 1.3%, 1.16% and 2.23% respectively compared with normal aggregate with 19.23%, 25.60% and 27.67% respectively. Coconut shell, however, has high percentage of water absorption capacity, elongation index and flakiness index of 23.72%, 26.69% and 86.12% respectively compared with that of normal aggregate of 1.80%, 8.78% and 36.89% respectively. Concrete specimen were produced with coconut shell as coarse aggregate, ordinary river sand as fine aggregate and ordinary Portland cement as binders. Trial mixes which include (1:1:1, 1:1½:2, 1:2:2, 1:2½:3, 1:1½:3, 1:2:4, 1:2:3, 1:3:3, 1:3:4, 1:4:4) were done and it was observed that mix ratio 1:1:1 and 1:2:2 gave good consistency and workability with water cement ratio 0.5. The mix ratio 1:1:1; 1:2:2 gave compressive strength of 16N/mm2 and 7.71N/mm2 at 28day strength test respectively. In addition Partial replacement of normal coarse aggregate with coconut shell was also carried out using the following percentages of 0%, 25%, 50%, 75% and 100% for a mix ratio1:2:4 .The results shows that 25% to 50% normal coarse aggregate replacement with coconut shell results gave 28N/mm2 and 22.5N/mm2 at 28day with water cement ratio 0.5.

USE OF COCONUT SHELL AS COARSE AGGREGATE IN LIGHTWEIGHT CONCRETE