Effects of interfacial transition zones on the stress–strain behavior of modeled recycled aggregate concrete

Based on nanoindentation tests and analysis, the constitutive relationship of the Interfacial Transition Zones (ITZs) in Recycled Aggregate Concrete (RAC) is put forward. Together with the meso/micro-scale mechanical properties of each phase in Modeled Recycled Aggregate Concrete (MRAC), the plastic-damage constitutive models are employed in numerical studies on MRAC under uniaxial compression and uniaxial tension loadings to predict the overall mechanical behavior, particularly the stress–strain relationship. After the calibration and validation with the experimental results, a parametric study has been undertaken to analyze the effects of ITZs and new mortar matrix on the stress–strain relationship of MRAC. It is revealed that the mechanical properties of new mortar matrix and relative mechanical properties between ITZs and mortar matrices play a significant role in the overall stress–strain relationship and failure patterns of MRAC under both uniaxial compression and uniaxial tension loadings.