Strength assessment of sustainable concrete using recycled concrete aggregate and steel slag

The growing use of natural aggregates in concrete manufacture has increased environmental concerns. Therefore, this study will focus on the feasibility of steel slag and RCA as partial substitutes in M40 grade concrete with respect to sustainable construction and valorisation of industrial wastes. The mixtures were prepared with various steel slag and RCA contents and were tested after 7 and 28 days for their compressive, flexural, and split tensile strengths. The findings indicated that concrete incorporating 40% steel slag substitution exhibited optimum mechanical performance. In addition, the combined use of steel slag and RCA maintained essential strength requirements, confirming that these by-products can replace natural aggregates effectively in structural-grade concrete. This research demonstrates that the inclusion of steel slag and RCA provides a sustainable alternative to natural aggregates by offering a data-driven experimental and statistical basis for environmentally friendly and resource-efficient concrete production.