混凝土窄条断裂区模型及其应用

以大量的实验观察结果为依据，提出了描述混凝土类半脆性固体材料失稳断裂前存在着裂缝稳定缓慢增长过程的窄条断裂模型．根据这一模型，提出了采用ＣＴＯＤｃ作控制参数来求解失稳断裂前的有效裂缝扩展量Δａｃ和等效断裂韧度～ＫＩＣ的计算方法．结果表明，将初始缝长ａ０加上Δａｃ进行有效裂缝长度修正后求得的～ＫＩＣ与试件尺寸无关，因而ＣＴＯＤｃ和～ＫＩＣ有希望作为控制混凝土类半脆性固体材料断裂的双参数准则．

Narrow strip model of fracture zone for concrete and its application

Based on a great many result of investigation ,a narrow strip model of the fracture zone for predicting the stable propagation of crack before unstable fracture is proposed. According to this model, methods of calculating effective fratcure toughness ~KIC and effctive length of crack growth before unstable frature, in which CTODc is taken as a control parameter, are suggested. The effective fracture toughness ~KIC is calculated by adding the effective length of crack growth before unstable fracture into the initial crack length. It is shown that the effective fracture toughness ~KIC is independent of the sizes of specimens. Therefore, CTODC and ~KIC could be taken as a doubleparameter criterion for evaluating fracture of the brittle materials ,such as concrete.