Waste glass powder on the properties of treated granular rubber modified concrete

The valorization of solid waste and efficient use of natural resources directly contribute to achieving Sustainable Development Goals (SDGs) No. 11 "Sustainable Cities and Communities" and No. 12 "Responsible Consumption and Production." This study aims to determine the optimal substitution ratio of sand with treated granular rubber (TGR) and subsequently evaluate the effect of replacing cement with waste glass powder (WGP) on the physical and mechanical properties of concrete. The experimental methodology followed two phases: First, fine aggregate was replaced with TGR at 2.5%, 5%, 7.5%, and 10% to identify the best-performing mixture. Second, using the optimal TGR proportion, cement was partially substituted with WGP at 4%, 10%, 16%, and 22%. Nine mix designs were prepared, totaling 180 specimens, with evaluations of workability, fresh density, temperature, air content, compressive strength, flexural strength, and modulus of elasticity at 7, 14, and 28 days of curing. Results indicate that TGR-modified concrete exhibited reduced density and improved workability, a trend that reversed in hybrid mixtures combining optimal TGR dosage with WGP as partial cement replacement. The 2.5% TGR + 16% WGP hybrid combination achieved mechanical performance improvements up to 54.76%, demonstrating viability for non-structural applications while promoting sustainable development through waste valorization.