Sustainable concrete production: Optimizing recycled aggregates with advanced treatments and marble dust as filler

This study explores the potential of treated recycled coarse aggregates (RCA) to enhance the properties of concrete, addressing the demand for sustainable construction materials. Two distinct treatments, Polyvinyl Alcohol (PVA) and Sodium Silicate + Fly Ash (SS + FA), are applied to the recycled aggregates. Natural aggregates are partially replaced by treated coarse aggregates at a 50% substitution rate, and concrete is produced using the sand envelope mixing method with varying levels of sand replacement. Additionally, the study assesses the impact of incorporating marble dust as a sand replacement in conjunction with the treated RCA. Extensive tests examine the mechanical, durability, and non-destructive properties of Recycled Aggregate Concrete (RAC) and conventional concrete. The findings reveal that RAC matches or even surpasses control concrete in terms of strength particularly showing improvements in PVA-treated aggregates with an impressive increase of 20.06% for PT 30. Uniformity is observed in ultrasonic pulse velocity (UPV) values and water sorptivity between RAC and control concrete. RAC exhibits higher water absorption and rebound hammer strength than control concrete. While all RAC specimens show increased permeability in the Rapid Chloride Penetration Test (RCPT), SFT 30 shows the highest enhancement of 44.84%, while PT 10 exhibits reduced permeability compared to control concrete. Thus, it can be concluded that treated recycled coarse aggregates have significant potential to enhance concrete performance and offer sustainable alternatives to traditional construction materials.