The accumulation of end-of-life tires and the rapid increase in demolition activities pose significant environmental and waste-management challenges. The redevelopment of construction materials incorporating this waste is a potentially promising strategy for minimizing environmental impact while promoting the principles of a circular economy. This study investigates the performance of self-compacting concrete (SCC) incorporating up to 20% rubber aggregates (sand and gravel) and 40% recycled concrete aggregate (RCA) for non-structural applications. A series of tests was conducted to assess fresh and hardened properties, including flowability, compressive strength, tensile strength, flexural strength, water absorption, and density. The results indicated that increasing RCA content reduced density and compressive strength, while tensile and flexural strengths were only moderately affected. Response surface methodology (RSM), utilizing a Box–Behnken design, was employed to optimize compressive, tensile, and flexural strength responses. Statistical analysis was used to identify the optimal mix proportions, which balance the mechanical performance and sustainability of SCC with recycled components. Mixtures incorporating moderate rubber content—specifically, 5–5.5% sand rubber and 0–6% coarse rubber—and 40% recycled-concrete aggregate (RCA) achieved the highest predicted performance, with compressive strength ranging from 20.00 to 28.26 MPa, tensile strength from 2.16 to 2.85 MPa, and flexural strength reaching 5.81 MPa, making them suitable for sidewalks and walkways. Conversely, mixtures containing higher rubber proportions (5.5–20% sand rubber and 20% coarse rubber) combined with the same RCA level (40%) showed the lowest mechanical performance, with compressive strength between 5.2 and 10.08 MPa, tensile strength of 1.05–1.41 MPa, and flexural strength from 2.18 to 3.54 MPa. These findings underscore the broad performance range achievable through targeted optimization. They confirm the viability of recycled materials for producing environmentally friendly SCC in non-structural applications.

This research investigates the effect of adding recycled rubber to concrete mixes as part of efforts to enhance environmental sustainability and improve the mechanical properties of concrete. The study focuses on evaluating the mechanical and physical performance of rubberized concrete by analyzing its properties such as compressive strength, tensile strength, and workability. Partial replacement of rubber by 0% to 15% of fine aggregate in concrete was studied, with standard tests conducted to determine the effect of rubber on overall performance. The importance of the research lies in providing a dual solution of reducing environmental waste from used tires, while improving some properties of concrete in non-structural applications. The results show that rubberized concrete achieves important advantages such as improved flexibility, abrasion resistance, and light weight, despite a slight decrease in compressive strength. The research also highlights the potential of using rubberized concrete in non-structural applications such as pavements, road barriers, and shock absorption systems. The research concludes by recommending further studies to improve the adhesion between rubber and concrete mix components, while exploring innovative applications to expand the use of rubberized concrete in sustainable construction projects.