Performance Evaluation of Recycled Self-Compacting Concrete Incorporating Recycled Concrete Aggregate and Recycled Steel Fiber

Self-compacting concrete (SCC) is an innovative type of concrete that can flow and settle into every corner of the formwork solely under its own weight, without segregating. It enables quicker placement, faster construction, and smooth movement around heavily reinforced areas. The use of waste materials in concrete production has grown significantly due to environmental and economic factors. Recycled concrete, as one such material, plays a role in reducing construction-related pollution. This approach not only enhances the efficient use of natural resources but also aids in environmental conservation, promoting a sustainable and eco-friendly construction industry [1], [24]. This study explores the use of recycled concrete aggregate (RCA) as a partial replacement for natural aggregate in self-compacting concrete (SCC) of grade C30/37.5. It aims to provide valuable insights into the practical application of recycled aggregate in advanced concrete production. RCA was used to replace coarse aggregate at levels of 25%, 50%, 75%, and 100% along with recycled steel fibers obtained from scrap tires. Recycled steel fibers were added at 0.25%, 0.5%, and 0.75% by volume of concrete. A control mix (plain SCC) was also prepared for comparison reasons The flow properties of SCC were evaluated through tests such as slump flow, J-ring, L-box, and V-funnel. The hardened properties including compressive strength, split tensile strength and flexural strength were tested after 28 days. The study concluded that the optimal replacement level for coarse aggregate with recycled aggregate combined with recycled steel fiber was 35% in SCC. Also using 0.25% or 0.50% waste steel fibers improves compressive strength, while a 0.75% fiber content leads to a reduction. However, the 0.75% fiber fraction achieves the highest splitting tensile and flexural strengths.