【摘要】 本文用试验的方法研究了混凝土的线弹性断裂性能.首先以79根试样测定了350^#凝混土的KIc为426.4千牛/米^3/2,450^#则为500.4千牛/米^3/2.关于凝混土KIc的尺寸效应问题,本文从脆性破坏统计理论导出了不同尺寸试样间KIc的换算公式,并进行了试验验证.应用声发射技术分析混凝土的裂纹扩展情况是有效的,本文介绍了这方面的试验和结果,并确定了混凝土的失稳扩展点.混凝土Ⅰ-Ⅱ复合型断裂的临界曲线和断裂角曲线是以40根（10种组合）斜裂纹试样和24根（6种组合）四点剪切试样的试验得出的,两类试样的结果十分接近.同时,还得出混凝土的KⅡc.更多还原

【Abstract】 In this paper the experimental method is used to study the linear elastic fracture properties of concrete. From 79 specimens, the kIc of 350# and 450# concrete are obtained strictly, being 426.4 kN/m^3/2 and 500.4 kN/m^3/2. Based on the statistical theory of brittle rupture, a conversion formula of kIc for the specimens of different sizes is derived considering the size effect of kIc of concrete and verified through experiments. The technique of acoustic emission is used to analyse the propagation of cracks and determine the instable cracking points of concrete. The fracture critical curves and the fracture cracking angle curves of mixed mode Ⅰ and Ⅱ of concrete are obtained from 40 inclined crack specimens（10 kinds of combinations） and 24 four-point shear ones（6 kinds of combinations）. The test results of these two types of specimens are very close to each other. The kIIc is also obtained from the tests.更多还原