Feasibility study of fine-metakaolin and coal bottom ash as cement and fine aggregate replacement in seawater-mixed concrete

Abstract

The combination effect of fine-metakaolin (FMK) and coal bottom ash (CBA) as cement and fine aggregate replacement in seawater-concrete was investigated to reduce environmental issues such as carbon emission, global warming, and insufficient water resource. Optimum percentages of 10%, 20% and 30% of fine-metakaolin was determined in Stage 1 through compression strength test. Stage 2 involved testing on mixture with FMK obtained in Stage 1 and 10%, 20%, 30%, 40% and 50% of CBA as the fine aggregate replacement. Nine series of concrete mixtures were prepared to conduct a compressive strength test and water absorption test at 7 and 28 days. It was observed that 10% of FMK and 10% of CBA incorporated with seawater had the highest compressive strength. Water absorption of the seawater-concrete mixed increased as the percentage of the CBA increased. It can be concluded that 10% to 50% replacement of CBA is suitable as the fine aggregate replacement with the substitution of FMK at 10%.