This study investigates the performance enhancement of recycled aggregate concrete (RAC) using supplementary cementitious materials (SCMs) and hybrid fibers (HFs). A binary mix containing 10% silica fume and 100% recycled coarse aggregate was used as the reference. Ternary blends incorporated 15% metakaolin and rice husk ash, 20% fly ash and waste glass powder, and 30% ground granulated blast furnace slag, evaluated with and without hybrid fibers (1% steel +0.5% glass fibers). Mechanical properties, including compressive strength, elastic modulus, and split tensile strength, were assessed alongside durability indicators such as water absorption, chloride penetration, and acid resistance. Results showed that SCMs primarily improved durability, while hybrid fibers significantly enhanced mechanical performance and acid resistance. The combined use of SCMs and HFs produced synergistic effects, yielding superior results compared to individual applications. Among all mixes, the blend containing 15% metakaolin and rice husk ash with hybrid fibers exhibited the best overall performance, achieving notable improvements in strength and reductions in water absorption and chloride penetration. Acid resistance was also significantly enhanced. These findings highlight the effectiveness of integrating SCMs and hybrid fibers in producing sustainable, high-performance RAC with improved mechanical and durability characteristics suitable for structural applications.
Al-Naghi et al. (Tue,) studied this question.