# Numerical and Experimental Investigation of Recycled Brick Coarse Aggregate Concrete
## 1 Introduction
[19] found that RBCA content significantly impacted the water absorption and dry density of the saturated surface of mixed recycled coarse aggregate. [PERSON] et al. [20] experimentally studied the NCA replacement of concrete with different ratios of RBCA. The results showed that the mechanical properties of RBCA concrete exerted no significant decline when the replacement rate was less than 20%. However, the mechanical properties of RBCA concrete decreased significantly when the replacement rate was up to 50% and above. All of these observations concluded that the addition of RBCA reduces the performance of recycled aggregate. In order to improve the application of RBCA concrete, scholars have studied the stress-strain relationship of RBCA concrete to support the structural design of recycled concrete and the numerical simulation calculation of recycled concrete. [PERSON] et al. [21] tested the influence of red brick aggregate content on the mechanical properties of recycled red brick concrete. The red brick replacement rate parameter was introduced to correct the existing stress-strain relationship of recycled red brick concrete and a corrected stress-strain equation was presented. [PERSON] et al. [22] established the constitutive damage model of recycled coarse aggregate concrete based on the Weibull function and equivalent strain principle. The constitutive relationship was modified by combining distribution and substitution rate functions. The presented model was able to satisfy the stress-strain relationship of recycled concrete with different mix and replacement ratios. [PERSON] et al. [23] defined four characteristic points of a typical hysteresis loop according to experimental testing and established the constitutive equation of RAC under cyclic loading. [PERSON] et al. [24] proposed a uniaxial compression damage constitutive model of recycled aggregate concrete considering the recycled aggregate replacement rate. [PERSON] et al. [25] introduced the shape parameter of the stress-strain curve to present a theoretical stress-strain relationship considering the strength and replacement rate of reclaimed coarse aggregate. Finite element numerical simulation can be used to numerically simulate the testing process, reducing the required test specimens and allowing more parameters to be investigated. Researchers have recently studied recycled concrete's mechanical properties and crack damage through experiments and finite element models. For example, [PERSON] et al. [26] proposed a stochastic aggregate model for simulating the failure mechanism of concrete in order to predict the mechanical behavior of recycled concrete. [PERSON] et al. [27] simulated the crack propagation process and mechanical properties of recycled concrete uniaxial compression specimens according to the damage plastic method of concrete. [PERSON] et al. [28] presented a computational modeling method for controllable regenerative aggregate shape parameters, which was then mapped to the finite element model through an image analysis program. This method can more accurately simulate the arbitrary aggregate shape and aggregate distribution. [PERSON] et al. [29] randomly placed concrete materials using the Monte Carlo method. They used a finite element model to analyze the uniaxial compression fracture of reinforced concrete with recycled aggregate content of 0%, 40%, 70%, and 100%. [PERSON] et al. [30] obtained the macroscopic stress-strain relationship and failure process of RAC under uniaxial stress based on the three-dimensional finite element method. [PERSON] et al. [31] used finite element software ABAQUS to simulate recycled concrete and study the mechanical differences between ordinary concrete and recycled concrete. [PERSON] et al. [32] established a stochastic convex aggregate recycled concrete model and evaluated the uniaxial compressive strength and damage process of RCCA. While there are many mechanical properties and mesoscopic mechanics of RCCA concrete, there have been relatively few studies on RBCA recycled concrete.