双参数模型法研究早龄期混凝土的断裂性能

本试验采用了RILEM推荐的“双参数模型”(TPM)(RILEM Technical Committee 89-FMT)研究了早龄期混凝土的临界应力集中因子KIC^3和临界裂缝尖端开口位移CTOD这两个断裂参数。试验同时采用普通混凝土和高强混凝土作为试验对象，取4根同一龄期的混凝土用于试验。试验龄期为12小时，1天，2天，3天，7天和28天。试验结果表明两参数值随水化的进行增大，相对于成熟混凝土来说，早龄期混凝土的这两个参数值比较低；在同一龄期，高强混凝土的这两个参数值要比普通混凝土的对应值高；从试验中还可以看出混凝土的断裂参数与强度有相类似的发展规律，可以作为材料的性能指标，用于表征混凝土的阻裂能力。

Fracture property investigation of young concrete using TPM

This paper presents the results of experimental investigations on the relationship between the age and fracture parameters of concrete. Test method is "two parameter model", including critical stress intensity factor Kjc and critical crack tip opening displacement CTODc. Four specimens are recommended for each type material tested. And three point bending was adopted. Both normal strength concrete and high strength concrete are chosen. Test ages are 12hours, 1 day, 2 days, 3days, 7days and 28days.Test results show that the values of these two parameters develop with the hydration, young concrete has lower Kc and CTOD, high strength concrete has higher Kc and CTOD than normal strength concrete at the same age and single edge notched beam specimen is plastic. Also, we can get from the test that fracture parameters are similar with the strength of concrete; all can be seen as the material property parameter to show the crack resistance capabilrty.