纤维混杂效应对混凝土弯曲韧性的改善

本文采用在C30混凝土中以不同的方式掺入玄武岩纤维与聚丙烯纤维,通过对8种单掺纤维混凝土试件和16种混杂纤维混凝土试件的弯曲性能进行试验研究,分析玄武岩纤维、聚丙烯纤维及其混杂纤维对混凝土弯曲力学特征的影响。试验结果表明,玄武岩纤维、聚丙烯纤维及玄武岩-聚丙烯混杂纤维的掺入对基体混凝土弯曲破坏时承受的最大荷载、破坏点挠度值和韧性指数均有很大的改善,其中,混杂纤维优于单掺纤维。混杂纤维对基体混凝土韧性指数提高最大达到18.1%。本文提出"纤维混杂效应函数"概念,并利用Matlab数据拟合出玄武岩-聚丙烯混杂纤维改善基体混凝土弯曲韧性的混杂效应函数。通过对混杂效应函数求极值,得到玄武岩-聚丙烯混杂纤维对基体混凝土弯曲韧性改善的最佳的体积掺加率,该值与试验数据基本一致。

On the Effect of Fiber Hybrid Effect on the Improvement of Concrete Flexural Toughness

C30 concrete matrixes were mixed with two kinds of fiber,basalt fiber and polypropylene fiber,in various ways.Experimental study was carried out for 8 kinds of single fiber concrete specimen and 16 kinds of hybrid fiber reinforced concrete specimen to analyze the effect of basalt fiber,polypropylene fiber and basah-polypropylene hybrid fiber on the concrete flexural toughness,respectively.Experimental results show that when concrete was in bending failure,basalt fiber,polypropylene fiber and basalt-polypropylene hybrid fiber all greatly improve the maximum load,the failure point deflection value and toughness index,among which,the effect of hybrid fiber is better than that of single basalt and single polypropylene fiber.The toughness index of concrete matrix mixed with hybrid fiber increases up to 18.1％.Meanwhile,the concept of "fiber hybrid effect function" is proposed in this paper.Hybrid effect function of flexural toughness of basaltpolypropylene hybrid fiber reinforced concrete was fitted,based on Matlab program.By finding the extremum of hybrid effect function,the optimal volume fraction of basalt-polypropylene hybrid fiber for matrix concrete flexural toughness was obtained,and the value is basically in agreement with the experimental data.