楔入式紧凑拉伸法确定混凝土的断裂能

本文采用楔入式紧凑拉伸法，对6组不同高度的36个楔入式紧凑拉伸试件进行了断裂试验，研究混凝土断裂能的确定方法和尺寸效应。根据断裂功的计算原理用所测得的荷载与裂缝张开口位移曲线，分别采用幂函数和指数函数拟合得到的尾部曲线对断裂能的贡献，计算出试件的断裂能。结果表明，两种函数拟合得到的尾部曲线有所不同，由此所计算出的断裂能也有一定差异，200mm高的试件的断裂能略小，当试件高度大于300mm后，断裂能不随试件高度的增大而变化，各种尺寸试件断裂能的平均值为204N/m。可认为采用本文试验方法所确定的断裂能在试验的试件高度范围内基本上是常值，无明显尺寸效应。

Determination of fracture energy of concrete using wedge splitting test on compact tension specimens

The wedge-splitting test with compact specimens is carried out to experimentally investigate the method for determining the fracture energy of concete and probable scale effect. The 36 specimens are divided into 6 sets with different dimensions. According to the principle of work-of-fracture the fracture energy of every specimen is calculated from the curve of P-CMOD with the contribution of tail section of the curve is taken into account. The result shows that the contributions of the tail section of the P-CMOD curve obtained from power function fitting are different from that obtained from exponential function fitting. The calculated fracture energy of specimen with height of 200mm is slightly lower than those of other specimens. However, in the range from 300mm to 1000mm, the fracture energy does not vary with the height of specimen. It may conclude that no size effect exists if the proposed test method for determining the fracture energy is adopted.