Abstract: Having studied the influence of pelypropylene fiber and expansive agent to plastic shrinkage of mortar through the experiment of the ordinary mortar、minorexpansion mortar、polypropylene fiber mortar and minorexpansion polypropylene fiber mortar,the result shows：Polypropylene fiber not only can efdectively decrease plasticity crack can also roduce the speed of crack expansion．Minorexpansion mortar shrinks when losing water．

Key words: polypropylene fiber, expansive agent, plastic shrinkage

摘要： 通过对普通砂浆、微膨胀砂浆、聚丙烯纤维砂浆及微膨胀聚丙烯纤维砂浆的塑性收缩试验，研究了聚丙烯纤维和膨胀剂对水泥砂浆塑性收缩的影响．结果表明：聚丙烯纤维不但能有效的减小砂浆塑性开裂而且还可以延缓塑性开裂的时间；微膨胀砂浆有失水回缩的特性．

关键词: 聚丙烯纤维, 膨胀剂, 塑性收缩