This study aims to enhance environmental sustainability in the construction sector by examining the mechanical and durability characteristics of polymer-treated recycled aggregate concrete (RAC). The incorporation of recycled concrete aggregates (RCA) in the manufacturing of RAC presents a viable strategy for mitigating environmental effects and advancing sustainable construction methodologies. The quality differences between natural aggregate (NA) and recycled concrete aggregate (RCA) are addressed by applying varying amounts of hydrophobic polymer to the aggregate in order to enhance the performance of RAC. The research methodically assesses the mechanical and durability characteristics of concrete by integrating treated recycled concrete aggregate at different substitution rates (25%, 50%, 75%, and 100%) as coarse aggregate. The results demonstrate that a 25% replacement with treated RCA improves compressive strength by 2.91% compared to conventional concrete (CC), while also enhancing durability by 3.21 to 9.28% for water absorption and acid resistance by 0.55 to 4.51% relative to concrete produced with untreated RCA. However, the application of polymer treatment may increase material costs and pose long-term durability uncertainties under varied environmental exposures. This study offers significant insights into enhancing environmental sustainability in construction through the optimisation of treated recycled aggregates in concrete manufacturing.