Studying the stress–strain behaviour of recycled aggregate concrete (RAC) is crucial for understanding the structural performance. This paper aims to investigate the stress–strain characteristics of RAC under uniaxial compression. Recycled aggregates, derived from construction and demolition waste, were used to partially replace natural aggregates in concrete mixes at various substitution levels. Experimental tests were conducted to evaluate the strain capacity of RAC. The results show that RAC exhibits a distinct stress–strain curve compared to conventional concrete, characterized by reduced peak strength, elasticity modulus, and increased strain capacity. The findings highlight the potential of RAC to meet structural performance requirements while promoting resource conservation and cost as well as waste reduction. Recycled aggregate (RA) is produced on-site using waste materials, reducing the need for transportation and project costs overall. According to a cost analysis, gradually substituting RA for natural aggregate (NA) results in considerable cost savings over time.