Properties of concrete incorporating recycled aggregate processed via a novel three-stage technique Available to Purchase

The use of recycled aggregate (RA) from construction and demolition waste in concrete reduces dependence on natural aggregate (NA) and supports sustainable construction. This study presents a triple-stage processing method to enhance RA quality through (i) pre-soaking in mild acetic acid for 24 h, (ii) mechanical grinding using a Los Angeles (LA) abrasion machine, and (iii) surface coating with a cement–silica fume slurry to fill micro-pores. The triple processed recycled aggregates (TPRAs) were categorised based on abrasion revolutions (RVNs): TPRA (0 RVNs), TPRA (100 RVNs), TPRA (200 RVNs), TPRA (300 RVNs), TPRA (400 RVNs), TPRA (500 RVNs), and TPRA (600 RVNs). M40 grade concrete mixes were prepared by replacing NA with TPRA, specifically 0%, 20%, 40%, 60%, 80%, and 100% to evaluate workability, strength, and durability properties of concrete. Among these, the mix with 60% replacement level of NA with TPRA (500 RVNs) showed a 12.84% reduction in compressive strength, but increased sorptivity (28%), drying shrinkage (19%), and rapid chloride penetration test value (34%) compared to the control mix. Despite strength reduction, the durability and environmental benefits suggest that 60% TPRA (500 RVNs) is a viable option for structural applications. The optimal process for high-quality TPRA involves 24-h mild acetic acid soaking, 500 revolutions in the LA abrasion machine, and cement–silica fume slurry coating.