桥梁工程用不同纤维混凝土弯曲韧性影响比较研究

Experimental study on bending toughness of fiber reinforced concrete for bridge engineering

为了提高桥梁工程用混凝土的弯曲韧性,考察了PVA纤维、钢纤维以及混杂纤维对混凝土弯曲韧性的影响。试验结果表明,当PVA纤维掺量为0.3%时,混凝土试件的抗弯拉强度、峰值载荷以及弯曲韧性指数均可以达到最大值;而随着钢纤维掺量的不断增大,混凝土试件的抗弯拉强度、峰值载荷以及弯曲韧性指数均呈现出逐渐增大的趋势,其中混杂纤维对混凝土弯曲韧性的增强效果明显优于单一PVA纤维和钢纤维;综合考虑桥梁工程用混凝土的弯曲韧性和施工成本等因素,推荐在混凝土中掺入混杂纤维,其中PVA纤维的最佳掺量推荐为0.3%,钢纤维的最佳掺量推荐为1.5%。

In order to improve the flexural toughness of concrete used in bridge engineering,the effects of PVA fi⁃bers,steel fibers,and hybrid fibers on the flexural toughness of concrete were investigated.The experimental re⁃sults showed that when the PVA fiber content was 0.3%,the flexural tensile strength,peak load,and flexural tough⁃ness index of concrete specimens all reached their maximum values.With the continuous increase of steel fiber content,the flexural tensile strength,peak load,and flexural toughness index of concrete specimens showed a grad⁃ually increasing trend.Among them,the reinforcement effect of hybrid fibers on the flexural toughness of concrete was significantly better than that of single PVA fibers and steel fibers.Considering the factors such as bending toughness and construction cost of concrete for bridge engineering,it is recommended to add hybrid fibers to the concrete.The optimal dosage of PVA fibers is recommended to be 0.3%,and the optimal dosage of steel fibers is recommended to be 1.5%.