The behavior of reinforced concrete two-way slabs incorporating waste plastic as partial replacement of coarse aggregate

This research focuses on using plastic water bottle caps (PWC), as a partial replacement for coarse aggregate in concrete. The compressive and flexural strengths were assessed. Mid-span deflection, mode of failure, and crack width have all been assessed for a simply supported reinforced concrete slab subjected to a concentrated load. Examined were six different plastic aggregate contents (by volume): 0%, 10%, 20%, 30%, 40%, and 50% PWC. Results showed that the best strength was at 10% PWC. It was noticed that the deflection of the slab decreased with a low content of PWC (≤ 30%). The reason for this result is that the shape of this type of aggregate makes it act like fibers in low percentages, which enhances their resistance to bending. For the reference slab, and compared to the theoretical failure pattern according to the yield lines theory, one can see that the failure pattern is very close to the theoretical pattern expected under concentrated load. The failure mode changed dramatically when 10% PWC was added. The slab members at failure were more interconnected, and the amount of deformation was less. Cracks appeared and extended between the quadrants as the plastic content increased.