Durability and strength characteristics of concrete through various experiments using treated recycled aggregates

In this study, recycled aggregate (RA) derived from construction and demolition waste (CDW) was used to replace natural aggregate (NA) in new concrete, aiming to reduce reliance on natural resources. The researchers introduced a novel method combining mild acetic acid pre-soaking with mechanical grinding to enhance RA quality. They tested six variations of treated recycled aggregates (TRAs), labeled TRA(0 min), TRA(3 min), TRA(5 min), TRA(7 min), TRA(10 min), and TRA(12 min), and used these to replace NA in an M40 grade concrete mix. Different replacement levels (0%, 25%, 50%, 75%, and 100%) were examined to evaluate their effects on concrete strength and durability. With 100% NA replaced by TRA(7 min), the compressive strength decreased by 15.95%, and the ISAT (Initial Surface Absorption Test) value increased by 17.14% compared to the control mix. Therefore, a 50% replacement of NA with TRA(7 min) is recommended for structural concrete. The optimal conditions for producing high-quality TRA were found to be 72 h of soaking in a 3% mild acetic acid solution, followed by 7 min of rotation in the Los Angeles Abrasion Machine.