研究了不同尺寸聚丙烯纤维混杂对水泥混凝土的力学性能、自由收缩、抗裂性能及抗渗性能的影响。结果表明:掺入纤维可以明显改善其性能,而不同尺寸纤维的混杂优于单一纤维,且不同长短纤维的最佳混杂比例介于5∶5~7∶3之间。从不同尺寸的纤维在相应结构层次上的叠加效应角度来阐述纤维混杂的作用机理。 The effects of different sizes of polypropylene fiber hybrid on the mechanical properties, free shrinkage, crack resistance and impermeability of cement concrete were studied. The results show that the incorporation of fiber can significantly improve its performance, while the mixing of different size fibers is superior to that of single fiber, and the best mixing ratio of the different length of fiber is between 5: 5 ~ 7: 3. From the perspective of the superposition effect of the different sizes of fibers at the corresponding structural levels, the mechanism of action of the fiber hybrid is described.