Utilization of Steel Slag Waste as a Substitute for Coarse Aggregate in Concrete Mixture

Abstract

Concrete is a crucial building material used for various structural components in buildings. It consists of cement, water, fine aggregate (sand), and coarse aggregate (gravel). This research focuses on the development of steel slag concrete as a replacement material for coarse aggregate, aiming to appropriately utilize steel slag waste, which poses environmental and health concerns. The study investigates the effect of substituting steel slag for coarse aggregate on the compressive strength of concrete and determines the optimal steel slag to normal concrete ratio. Concrete samples aged for three, seven, and 28 days were prepared using SNI 7656:2012, incorporating different proportions of steel slag as a substitute for coarse aggregate. Results indicate that variations of 20%, 40%, and 60% show improvements in comparison to normal concrete after three and seven days of curing. However, the variations of 80% and 100% are less commonly used than standard concrete. The increase in compressive strength of steel slag concrete aged 28 days, compared to normal concrete, for variations of 20%, 40%, and 60% is 1.54%, 3.00%, and 6.57%, respectively, while the reduction for variations of 80% and 100% is 7.93% and 18.80%. Based on the results, steel slag concrete with a 60% substitution of coarse aggregate exhibits the optimal compressive strength ratio in the mixture.