Performance Study of Sustainable Concrete Containing Recycled Aggregates from Non-Selected Construction and Demolition Waste

In the present study, we investigated the mechanical performance of concrete composed of non-selected construction and demolition waste (C&DW) sourced from both old and new sections of an inactive waste landfill site in Karaj, Iran. Initially, we determined the composition of the coarse and fine C&DW used in concrete production. Subsequently, we meticulously examined the physical and chemical properties of both the C&DW and virgin materials to enable thorough comparisons of the results. We then conducted experimental analyses on 33 concrete mixtures containing recycled C&DW, utilizing various tests, including a compressive strength test (CST) for cylindrical and cubic samples, modulus of elasticity (MOE), wide wheel abrasion test (Capon test), British pendulum number (BPN), and ultrasonic pulse velocity (UPV) test. We considered both non-separated fine and coarse C&DW at different replacement ratios in the recycled concrete (RC). Our findings indicate that using non-separated coarse and fine C&DW in concrete yielded satisfactory results, leading to significant savings in virgin materials required for concrete preparation and promoting sustainable development. Furthermore, non-selected C&DW proved to be a viable sustainable material for similar concrete applications. The results revealed a decrease in brick material consumption in various constructions over the past 20 years in Karaj, contributing to the enhanced strength of C&DW concrete. However, the presence of clay minerals in aged landfill sites can adversely affect concrete performance as a potential destructive factor. Despite the possible negative impact of incorporating fine recycled C&DW materials on concrete mechanical performance, the Capon test results demonstrated that the presence of coarse C&DW can enhance concrete’s wear resistance.