利用楔劈拉伸试验研究混凝土的断裂特性

Study about the Fracture Properties of Concrete Using Wedge split Tensile Test

利用改进了的楔劈拉伸试验方法，对尺寸为２００ ｍ ｍ ×２００ ｍｍ ×１００ ｍ ｍ 的小型试件在不同的预制裂缝（ 初始裂缝）下的混凝土的开裂、裂缝稳定扩展进行了研究．试验结果表明，利用Ｓｈａｈ 等人提出的双参数模型所求得的混凝土稳定断裂韧度ＫｓＩｃ 与混凝土的初始裂缝长度ａ０ 无关，同时还发现混凝土临界裂缝尖端张开位移ＣＴＯＤｃ 及裂缝过程区长度ａｅ 与初始裂缝长度ａ０ 成反比关系．由于该方法所得到的结果同相应的三点弯曲试验所得到的结果几乎一致，因此其有可能成为判断混凝土失稳断裂材料参数的方法．

By using the improving wedge split tensile testing method, the crack of the concrete and the stable development of crack were researched. The samples of 200 mm×200 mm×100 mm under the different prefabrication condition were used. The test results showed that the stable fracture toughness K s Ic obtained by the double parameter model (suggested by S.P. Shah) has nothing to do with the initial crack length a 0. Meanwhile, we found that CTOD c and a e are inversely proportional to a 0. For the conclusion of this paper is almost coincide with three point bending test, it is possible to decide the unstable crack parameter of concrete material through this improving testing method.