不同龄期混凝土断裂试验研究

为探究不同混凝土的双K断裂参数和材料基本参数(抗压强度、劈裂抗拉强度、弹性模量)的内在联系,开展了龄期为2,3,7,21,28,60,90 d混凝土的力学性能试验及三点弯曲梁断裂试验,分析了不同龄期混凝土的力学性能与断裂性能。结果表明:混凝土的抗压强度、劈裂抗拉强度、弹性模量与双K断裂参数随龄期的变化趋势基本一致;各个龄期混凝土的双K断裂参数与材料基本参数近似满足双线性关系。以材料基本参数作为输入参数,借助扩展有限元软件模拟不同龄期试件的断裂过程,得到各个龄期下的P-CMOD曲线及双K断裂参数计算值,与实测结果对比,两者吻合良好。

Test and analysis on concrete fracture at different ages

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.