Sustainable infrastructure solution using slag and non-metallic polymer within waste aggregate concrete: Characterization and Optimization with TOPSIS

In recent years, significant attention has been directed toward the development of sustainable construction materials, particularly focusing on fine and coarse aggregates. Although numerous studies have investigated the use of alternative materials as replacements for conventional aggregates, considerable scope remains for further exploration. Addressing this complex, multi-criteria decision-making problem, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was employed in the present study. This method facilitates the identification of the most suitable alternative by selecting an option that minimizes the distance from the ideal solution while maximizing the distance from the negative-ideal solution, thereby enabling a rational and systematic comparison among different mix alternatives. This research investigates the effects of partial substitution of natural sand with copper slag, steel slag, and rubber waste in rates of 10%, 20%, and 30% in concrete. Different combinations of concrete were tested against standard concrete after 28 and 42 days of curing. Experimental results were further processed using numerical modelling techniques to enhance the reliability of the conclusions. Out of the combinations, the one with 20% copper slag, 20% steel slag, and 10% rubber waste had a better performance in strength and durability when compared to conventional concrete. However, more research is necessary to gain and determine deeper insights into the long-term performance and sustainability of the alternative materials over the long term. The novelty of this research lies in the synergistic incorporation of slag and non-metallic polymer within waste aggregate concrete to develop a high-performance sustainable construction material.