混杂纤维高强混凝土断裂性能试验研究

Experimental study on fracture properties of hybrid fiber reinforced high-strength concrete

采用楔劈拉伸试验方法,对14组共42个混杂纤维(钢纤维-聚丙烯纤维)高强混凝土试件进行楔劈拉伸试验,研究混杂纤维高强混凝土的断裂性能。研究结果表明:在钢纤维体积率为1.5%、聚丙烯纤维掺量为0.6kg/m3时,混杂纤维高强混凝土表现出较好的断裂韧性,但随着聚丙烯纤维掺量的增大,其增韧效果变化不大;当聚丙烯纤维掺量为0.9kg/m3时,混杂纤维高强混凝土断裂韧度、断裂能、裂缝嘴张开位移及其增益比均随钢纤维体积率的增加表现出良好的增加趋势;钢纤维在高强混凝土断裂性能的改善方面起着主导作用,随着钢纤维体积率的增加,聚丙烯纤维的增韧作用逐渐减弱;钢纤维类型对混杂纤维高强混凝土的断裂性能具有不同程度的影响。

Through the test on fracture properties of steel fiber and polypropylene fiber hybrid reinforced high-strength concrete（S-PFRHSC） with 42 specimens by means of the wedge-splitting tension, the fracture behavior of S-PFRHSC was investigated. The results show that S-PFRHSC exhibite better fracture toughness when the volume fraction of steel fiber is 1.5% and the polypropylene fiber content is 0. 6kg/m^3 , but the increasing extent on fracture toughness is smaller with the increase of the polypropylene fiber content. All of the KIC, GF, critical crack mouth opening displacement CMODc and their ratio of gains increase with the increase of the volume fraction of steel fiber when the polypropylene fiber content is 0. 9kg/m^3. Steel fibers exhibites dominant action on improving the fracture behavior of S-PFRHSC than polypropylene fiber, the toughening effect of the polypropylene fiber reduces gradually when the volume fraction of steel fiber increases. Varying degree of influences of steel fiber types on the fracture properties of SPFRHSC are identified.