混杂纤维对铁路工程粉煤灰混凝土力学与耐久性能的影响研究

Research on the Influence of Hybrid Fiber on the Mechanical and Durability Performance of Fly Ash Concrete in Railway Engineering

在混凝土中添加2种不同长度的纤维材料有利于提升其力学性能和耐久性能。基于此,制备了玄武岩纤维和聚丙烯纤维的质量比1∶2的混杂纤维添加粉煤灰混凝土试件,混杂纤维掺量分别为0、0.2%、0.4%、6%和8%。测试了混凝土的抗压强度、劈裂抗拉强度、抗碳化深度以及冻融循环20、40、60、80和100次后的抗压强度和质量损失率,研究了混杂纤维添加后混凝土的力学与耐久性能。结果表明:铁路工程粉煤灰混凝土抗压强度和劈裂抗拉强度均随混杂纤维掺量的增大而先增大后减小;混凝土的碳化深度和冻融质量损失率随混杂纤维掺量的增大而先减小后增大;综合分析混凝土的力学与耐久性能,最佳混杂纤维掺量为0.2%~0.4%。

Adding two fiber materials of different lengths to concrete is beneficial to improve its mechanical properties and durability. Based on this, a hybrid fiber-added fly ash concrete specimen with a mass ratio of basalt fiber and polypropylene fiber of 1∶2 was prepared, and the hybrid fiber mass fraction was 0, 0.2%, 0.4%, 6%, and 8%,respectively. The compressive strength, splitting tensile strength, carbonization resistance of concrete, and the compressive strength and mass loss rate after freeze-thaw cycles of 20, 40, 60, 80 and 100 times were tested, and the mechanics and durability of the concrete specimens after adding the hybrid fiber were studied. The research results showed that the compressive strength and splitting tensile strength of fly ash concrete in railway engineering first increased and then decreased with the increase of the mixed fiber mass fraction;the carbonation depth and freeze-thaw mass loss rate of concrete first decreased and then increased with the increase of the mixed fiber mass fraction.Comprehensive analysis of the mechanical and durability properties of concrete proved that the best mixed fiber mass fraction was 0.2%~0.4%.