Evaluation of geotechnical characterization of recycled sand as a sustainable replacement for natural sand

The world is facing a significant challenge due to substantial production of construction and demolition waste (CDW), leading to accumulation of landfills. The escalation of construction activity in urban and rural regions, driven by rapid urbanization, intensifies the challenge of increased CDW. To overcome and address the concerns about environmental sustainability, the use of recycled materials in diverse engineering infrastructure applications needs to be recommended. Recycled sand (RS) is one of the major by-products of CDW that is capable of being used in various infrastructure applications. To ensure the use of recycled sand as an alternative material to substitute natural sand (NS). Extensive laboratory tests such as micro-, macro-, and large-scale testing were carried out using large-scale direct shear test, plate load test, and a lightweight deflectometer test, to evaluate the physical and mechanical characteristics of recycled sand. In addition, the results were compared with natural sand in terms of bearing pressure (q), deformation modulus (E_PLT and E_LWD) of unreinforced, mechanically reinforced RS and NS samples, and its corresponding modulus improvement factor (MIF). The results indicate that the behavior of recycled sand was observed as similar to unreinforced and reinforced natural sand fill, and conclude that the recycled sand is a feasible material in substituting the natural sand for geotechnical engineered applications such as embankment fills, sandy subgrades, filler layers, and mechanically stabilized earth walls.