Microstructural and other properties of copper slag-coal bottom ash incorporated concrete using fly ash as cement replacement

Increased demand for concrete leads to an increase in utilization of cement and sand, and increased consumption of cement leads to increased CO2 emissions. Furthermore, mining restrictions in certain areas and the growing need for natural ecological sustainability lead to additional problems with river sand availability. This study promotes the utilization of industrial waste in concrete for long-term environmental sustainability and safe disposal. Out of various types of industrial byproducts, combined use of copper slag and bottom ash as sand and simultaneously fly ash as cement, the replacement has not yet been studied out. Hence, the primary goal of this research was to evaluate their usage in concrete to replace sand with copper slag and coal bottom ash waste, as well as cement with fly ash. Concrete mixtures were made using varying amounts of waste copper slag (CS) and bottom ash (CBA) (0-60%) in equal proportions as a partial substitute for natural sand, as well as fly ash (0-30%) as cement. Slump, unit weight, split tensile strength, compressive strength, and microstructural characteristics such as X-ray diffraction, SEM, and EDS of concrete mixtures were investigated. Test results reveal that workability, compressive and split tensile strength improve with increment in percentage replacement of FA, CS, and CBA. Improvement in strength with the percentage replacement is also confirmed by change in morphology by SEM and X-ray diffraction analyses.