Ⅱ型荷载下混凝土剪切断裂的测试研究

Study on the Test of Concrete Shear Fracture under Mode Ⅱ Loadings

有关混凝土的断裂行为己被广泛研究,但很少是针对剪切断裂的情况.本文采用 型(四点剪切)加载,进行一系列测试,研究了混凝土单边预制裂纹(SEN)直梁剪切断裂的技术和条件.初步实现了混凝土的剪切断裂,测得混凝土的 型断裂韧度因子K C.实验结果显示,试件的几何尺寸越大,养护的龄期越长,实验效果越理想,在这两个因素中,试件尺寸的影响更明显.此外,混凝土的配合比与粗集料对测试结果也有重要影响,而细集料的影响似乎并不明显.同时,文中对实验结果进行了详细的分析,最后,得出一些具有工程实用价值的结论.

Extensive research has been done on the fracture behavior of concrete, but very little on shear fracture. In this paper, the fracture performances of singleedge notched (SEN) concrete beams under mode Ⅱ (fourpointshear) loadings, as well as the shear fracture behavior of concrete, are reported, and the mode Ⅱ fracture toughness factors of concrete are gained. The experimental results indicate that with bigger size of specimen and the recuperating age longer, it is easier to achieve ideal effect, and the effect of specimen size is more evident between these two factors. Furthermore, the mix ratio of concrete and the size of coarse aggregation have also effect on the results of test, but it seems that the effect of the fine coarse aggregation is not evident. The results of experiment are analyzed in detail.