摘   要：通过室内试验对比分析了钢纤维和聚丙烯纤维掺量、钢纤维单掺、聚丙烯纤维单掺和钢纤维—聚丙烯纤维混杂对混凝土高温抗渗系数（Ccp）的影响，并研究了降温方式对钢纤维混凝土Ccp的影响。试验结果表明，温度越高Ccp越大，随钢纤维掺量的增加，Ccp逐渐减小，而Ccp随聚丙烯纤维掺量的增加出现先减小后增大的趋势，当聚丙烯纤维掺量为0.05%时，Ccp最小；在混凝土中添加钢纤维、聚丙烯纤维和混杂纤维，分别使Ccp降低33.7%、26.6%和42.7%，表明混杂纤维对混凝土的高温抗渗性能改善效果最好；将钢纤维混凝土加热至相同温度，自然降温时抗渗性能最好，洒水降温次之，淬冷时抗渗性能最差，随着温度的升高，三者引起的抗渗性能差异逐渐减小。

 Abstract：In order to study the impermeability of fiber concrete at high temperature, the effect of the content of steel fiber and polypropylene fiber, single-doped steel fiber and polypropylene fiber and co-doped of steel fiber and polypropylene fiber on the high temperature impermeability coefficient (Ccp) of concrete and the influence of cooling mode on Ccp of steel fiber reinforced concrete are studied based on the indoor test. The test results show that the higher the temperature，the higher Ccp of concrete. And with the increasing of the fiber content，Ccp of concrete decreases gradually, while with the increasing of polypropylene fiber content, Ccp of concrete increases at first and then decreases. When the polypropylene fiber content is 0.05%，Ccp of concrete is minimum；by adding steel fibers, polypropylene fibers and hybrid fibers into the concrete, the Ccp of concrete at high temperature will fall 33.7%, 26.6%and 42.7% respectively, which indicates the improvement effect of hybrid fiber on the permeability performance at high temperature is best； after heating the steel fiber concrete to the same temperature, it’s found that the impermeability of concrete is the best by the mode of natural cooling, and quenched is the worst cooling mode for the impermeability of concrete, but with the increasing of temperature, the differences of concrete impermeability caused by these cooling modes are gradually reduced.