Feasibility of waste copper slag with coal bottom ash in concrete as partial substitution of fine aggregate

Copper (Cu) slag is a by-product of copper industries whereas Coal BA (bottom ash) is a waste product of thermal power plants. The objective of this research study was to examine the compressive strength parameters and microstructure investigation like SEM, EDS, and XRD of concrete-incorporated waste Cu slag and Coal BA as partial substitutes of fine aggregate. Compressive strength in 7 and 28 days curing ages, and 1 day and 28 days unit weight were assessed experimentally. Experiment results show that the workability of the fresh mix first slightly decreases and then increases with an increase in sand replacement. There is no remarkable difference seen in 1 day and 28 days unit density of design concrete mixes with reference to control concrete. Effect of combined utilization of waste Cu slag and coal BA improves the compressive strength up to 50% replacement with reference to control concrete (without substitution of river sand) in concrete. As compared to the reference mix, the design concrete mix containing Cu slag and coal BA gives the higher initial strength. Scanning electron micrograph of concrete samples shows the development of C-S-H gel, calcium hydroxide, and ettringite and change in morphology by the replacement.