Utilization of recycled construction and demolition waste to improve the bearing capacity of loose sand: an integrated experimental and numerical study

Abstract

ABSTRACT The present study examines the efficacy of the thickness of recycled construction and demolition waste (RCDW) layer (0.4D, 0.6D, 0.8D, 1D and 1.2D; D: diameter of footing) prepared at different relative densities (30%, 50% and 70%) overlaying on loose sand. Two sizes of RCDW, 5 mm named RCDW-I and 10.6 mm named RCDW-II, were used in this investigation. The plate load test and finite element analysis using ABAQUS were carried out on different combinations. Moreover, a large box direct shear test was conducted to determine the angle of internal friction (α) of RCDW-I and RCDW-II at relative densities (ID) of 30%, 50% and 70%. With the usage of RCDW layer over sand, the ultimate bearing capacity increases by 640% for RCDW-I and 597% for RCDW-II, and the corresponding decrement in the settlement was 36.86% and 33.54% (at ID = 70% and u = 1.2B), respectively. The conjoined analysis shows that RCDW-II performs better than RCDW-I at lower ID. Whereas the opposite trend is witnessed at higher ID. The experimental results were compared to the numerical model created in ABAQUS 3D. In addition, regression analysis was performed using SPSS software to build empirical expressions of the given results.