关键词: 混凝土, 龄期, 双K断裂参数, 材料基本参数, 扩展有限元法

Abstract: In order to explore the intrinsic relationship between the double-K fracture parameters of the concrete and the basic material parameters (compressive strength, splitting tensile strength, elastic modulus), the mechanical performance test and the three-point bending beam fracture test on concrete samples at different ages are carried out, and effects of the age on the mechanical and fracture properties of the concrete are analyzed. The results show that the variation law of compressive strength, the splitting tensile strength, the elastic modulus and the double-K fracture parameters with age are basically the same. The double-K fracture parameters of the concrete at different ages pose double-linear relationships with the basic parameters. Taking the basic material parameters as input, the XFEM software is used to simulate the fracture process of specimens at different ages. The P-CMOD curves and the calculated values of the double-K fracture parameters are obtained at each age, and the results were in good agreement with the measured ones.

Key words: concrete, age, double -K fracture parameters, basic material parameters, XFEM