Interface Damage Mechanism and Mechanical Properties of Carbon Fiber Recycled Concrete Based on M‐C Simulation Model

With the increasing prominence of construction waste accumulation and resource shortages, the application of recycled concrete has attracted much attention. Addressing the issues of weak interfacial transition zones and insufficient mechanical properties in recycled concrete, this study constructs an interfacial damage analysis model for carbon fiber (CF) recycled concrete based on Monte Carlo stochastic simulation and plasticity theory. The influence of CF parameters and concrete matrix properties on interfacial damage behavior and mechanical properties is systematically investigated. Numerical simulation and plasticity experiments were conducted to explore the effects of various CF lengths and volumetric admixtures on the mechanical properties of CF recycled concrete. Experimental results show that when the CF length is 8 mm and the volumetric admixture is 0.3%, the compressive, tensile, and flexural strengths of CF recycled concrete are increased by 18.7%, 48.3%, and 41.5%, respectively, compared with recycled concrete without CF. However, excessive admixture easily causes fiber agglomeration, leading to a decrease in strength gain. Furthermore, the mechanical properties of CF recycled concrete reach their optimal level when the concrete grade is C60. This study can reveal the interfacial damage mechanism and quantify performance improvements, promoting the mix design optimization and engineering applications of CF recycled concrete.