摘   要：研究了高弹模聚乙烯醇纤维和低弹模聚丙烯纤维及其共同作用对混凝土力学性能和早期抗裂性能的影响，同时研究了混杂纤维、减缩剂及两者复掺对混凝土早期塑性收缩和干燥收缩的影响，讨论了复掺纤维和减缩剂对混凝土抗裂和收缩性能的作用机理。结果表明，纤维可明显提高混凝土的力学性能，改善抗裂能力，其中混杂纤维的效果要优于单一种类的纤维；减缩剂可显著降低混凝土塑性和干燥收缩，但与纤维复掺时作用效果稍有降低，需要采取适当措施保证纤维混凝土中减缩剂作用的发挥。

Abstract: The influences of polyvinyl alcohol fiber, polypropylene fiber and hybrid fibers on the mechanical property and early age crack resistance of concrete are investigated. Meanwhile, the combined effects of fibers and shrinkage-reducing agent on the plastic and dry shrinkage of concrete are studied. The mechanism of combined effects of fibers and shrinkage-reducing agent on crack resistance and shrinkage reduction of concrete is discussed. The results indicate that the mechanical property and crack resistance are obviously improved by fibers, and hybrid fibers have better effect than any other single kind fiber. The plastic and dry shrinkage of concrete are evidently reduced by shrinkage-reducing agent. When combined with fiber, the effect of shrinkage-reducing agent slightly decreases. The adequate measures are taken to ensure the normal effect of shrinkage-reducing agent in fiber reinforced concrete.