Exploring the role of recycled aggregates in modern concrete technology

Abstract

This research evaluates the performance of concrete mixtures incorporating fly ash, Ordinary Portland Cement (OPC), and varying proportions of recycled coarse aggregate (RCA) along with natural coarse aggregate (NCA). The study including slump, compressive strength, split tensile strength, flexural strength, sulfate resistance, and water absorption, to determine both the mechanical properties and the durability of the concrete mixes. The slump test revealed a reduction in workability with increasing RCA content, while the compaction factor indicated improved compactness in these mixes. Compressive, tensile, and flexural strength tests showed enhanced strength characteristics for mixes with up to 20% RCA, outperforming conventional concrete at 28 days. Sulfate resistance tests indicated that increasing RCA content reduced durability, while flyash improved resistance in certain mixes. Water absorption tests demonstrated con-sistent increase in absorption with higher RCA proportions, highlighting the difference between sustaina-bility and durability. The results were analyzed using ANOVA, confirming statistically significant variations in performance across different mixes. The study concludes incorporating RCA with flyash can improve strength properties while slightly compromising durability. This work underscores the potential of recycled aggregates in sustainable concrete production and provides a framework for optimizing concrete mixes balance environmental benefits with mechanical and durability performance.