Constitutive model of waste brick concrete based on Weibull strength theory

This paper presents a method to establish the constitutive relation of Waste brick coarse aggregate recycled concrete (WBC) based on Weibull strength theory. The damage of WBC material under uniaxial compressive stresses is simulated based on a parallel bar system. The principal structure model of uniaxial compression of recycled concrete with different waste brick contents is derived from the Lemaitre strain equivalence assumption and Weibull strength theory. The constitutive models of recycled concrete under uniaxial compression with different waste brick contents were presented. The parameters of the constitutive model of WBC are calculated by combining the results of uniaxial compressive tests of WBC. The failure pattern of WBC after the compressive test is observed. The mechanism of its destruction is investigated by scanning electron microscopy (SEM). Finally, the proposed model is compared with the finite element simulation results, and the difference in constitutive relations between the two methods is analyzed. The results show that, due to the weakness of WBC itself, the integrity of concrete after compression gradually decreases with the increase of WBC content. The error between the experimental results and the derived formula is small, which verifies the rationality of the proposed model. The initial damage of concrete is caused by adding WBC, and the total damage variable increases monotonically with the increase of strain in the S-shape. The numerical simulation results show a significant stiffness and a slightly leftward intrinsic curve compared to the proposed model.