Effect of Rubber and Steel Fibers Obtained from Waste Tires on Mechanical and Physical Properties of Concrete: An Experimental Study

This study investigates the incorporation of rubber particles and steel fibers, derived from end-of-life vehicle tires, into concrete as partial replacements for fine aggregates, with the goal of enhancing sustainability in construction materials. Twelve concrete mixtures containing varying proportions of rubber (5%, 10%, and 15%) and steel fibers (0.4% and 0.8%) were prepared. The mechanical and physical properties of these mixtures were evaluated through compressive and flexural strength tests, ultrasonic pulse velocity measurements, water absorption analyses, and scanning electron microscopy. The results showed that while rubber reduced compressive strength and increased porosity, it improved flexibility at low contents. In contrast, steel fibers increased density and flexural strength, and counteracted the negative effects of rubber by reducing internal voids and inhibiting crack propagation. The combined use of rubber and steel fibers yielded a complementary improvement in both mechanical performance and durability. These findings confirm the technical feasibility of incorporating waste tire materials into concrete and underscore their relevance in sustainable construction practices.