Numerical and experimental studies on fracture process of recycled concrete

Abstract

ABSTRACT In this paper, an improved lattice model of heterogeneous cohesive frictional solids is developed to simulate the fracture process of recycled concrete under tensile and compressive loadings. In this numerical simulation, the recycled concrete is considered as a composite material of five phases, including natural aggregates, old hardened mortar (HM), new HM, new interfacial transition zone (ITZ) and old ITZ. In addition to the numerical simulation, a series of laboratory tests are designed to investigate the failure process of the recycled concrete. The fracture process of the numerical simulation is in a satisfactory agreement with the experimental observations. It is demonstrated that the cracks always appear around ITZs at first, extend to old HM secondly and then to new HM in the recycled concrete. Under the condition of this investigation, the simulated stress–strain relationship of recycled concrete is fit well with the laboratory test results under tensile loadings.