Assessing the influence of construction and demolition waste materials on workability and mechanical properties of concrete using statistical analysis

In recent decades, because of the massive destruction of old structures, a large amount of construction and demolition (C&D) waste has been produced. These waste materials have the greatest volume and weight among solid waste with many environmental problems. Reusing them in concrete as substitute to virgin aggregates is considered an efficient practice unless significant mechanical properties and workability degradation occurs. In this study, the effect of different concentrations of C&D waste (0%, 10%, 20%, 30%, and 50%) as coarse aggregates on workability, compressive, tensile, and flexural strengths was investigated at the water-to-cement (W/C) ratios of 0.40, 0.45 and 0.50. The strengths were measured at the ages of 7 and 28days. The results proved that C&D waste has no significant effect on compressive strength, while its negative impact on workability was palpable. With respect to tensile and flexural strength, just 50% of C&D waste led to significant reduction.