中文摘要：

通过正交化试验设计,研究常温下、受热150℃后钢纤维、聚丙烯纤维、粉煤灰对混凝土弯曲性能的影响,并进行钢纤维混掺、单掺、不掺的混凝土弯曲性能的对比。从试验结果的方差分析以及对比试验数据可以得出：（1）在混凝土中掺入钢纤维能够明显改善混凝土的弯曲性能,尤其是长度较大的钢纤维;（2）钢纤维的混掺对于混凝土弯曲性能的增强效果仅在受热前优于钢纤维的单掺;（3）高强混凝土的弯曲性能远不如强度等级低于它的钢纤维混凝土。

英文摘要：

By the orthogonal test design, the effect which steel fiber,polypropylene fiber and fly ash had to the flexural properties of concrete is researched at normal temperature and being heated to 150℃ ,meanwhile ,the flexural properties among the concrete which is classed by hybrid steel fiber, sole steel fiber and no fiber is compared.The conclusion is got from the variance analysis and the compare of test data： （ 1 ）steel fiber mixed into concrete can improve markedly the flexural properties of concrete, especially long steel fiber; （2）the increasing effect which hybrid steel fiber had to the flexural properties is better than sole steel fiber only before being heated; （ 3 ）the flexural properties of high strength concrete are lower than steel fiber concrete which compressive strength is lower.