Experimental Study on Cement and Fine Aggregate Replacement with Coal Bottom Ash in Seawater-Mixed Concrete

Abstract

An experimental studywas carried out tostudy the properties of concrete madewith seawater as total mixing water, ground coal bottom ash as binary cement and coal bottom ashas sand replacement.The first stage mixes were prepared with three percentages (0, 10, 20 and 30) of ground coal bottomash as partial replacement of binder.The second stage mixes involved10 percent of ground coal bottom ash with 25%,50%, 75% and 100% of coal bottom ash replacing naturalsand. Properties investigated were materials properties,binderchemical composition,concretehardened density,compressivestrength,and SEM. Test on hardened density was conductedon 7 and 28 days. Ground coal bottomash was identified as Class F, while coal bottom ash has lowspecific density and high-waterabsorption compared to naturalsand.Concrete density andcompressive strength decreased on use of coal bottom ash as fine aggregate. Compressive strength was seen to decrease as CBA percentagerose, with the maximum value being 44.4 MPa for combination of 10 percent ground coal bottom ash and 25 percent coal bottom ash.Series with 10% CBA (ground coal bottom ash) reduces by roughly 51% while maintaining a sufficient structural strength value.The findings of this investigation showed that it is possible to produce seawater-concrete, which incorporates coal ashin concrete.