研究了聚丙烯纤维在混凝土中的阻裂效应 ,比较了不同细度聚丙烯纤维阻止混凝土塑性开裂效应的强弱。研究结果表明 :聚丙烯纤维能有效阻止混凝土发生塑裂 ,阻裂效应随纤维细度的增大而增强。另外还对混凝土塑性开裂和纤维的阻裂机理进行了分析 The effect of polypropylene fiber in concrete cracking was studied. The effect of polypropylene fiber with different fineness on the plastic cracking of concrete was compared. The results show that polypropylene fiber can effectively prevent the plastic deformation of concrete, and the effect of blocking resistance increases with the increase of fiber fineness. In addition, the plastic cracking of concrete and the fiber crack resistance mechanism were also analyzed