盐冻耦合作用下掺纤维面板混凝土耐久性研究

为了研究盐冻耦合作用下掺纤维面板混凝土的耐久性问题，采用不同纤维种类（聚丙烯、聚丙烯腈、钢纤维）及不同掺量的面板混凝土在不同氯盐浓度（2.0%、3.5%、5.0%）中进行冻融循环试验，并对冻融后的试件开展电镜扫描试验。研究表明：当盐冻侵蚀作用增强时，掺纤维面板混凝土试件的质量损失率先减小再增大，抗压强度则持续降低；氯盐浓度对盐冻耦合作用影响较大，其中氯盐浓度为3.5%时试件的质量损失率最高，抗压强度降低最快；不同类型的纤维可以有效地改善面板混凝土的抗盐冻性能，聚丙烯和聚丙烯腈纤维掺量在1.0 kg/m³时、钢纤维掺量在70 kg/m³时，试件的质量损失率较少，抗压强度降低幅度较小，抗盐冻性能较好。

Study on concrete durability of fiber doped panels under salt-freezing coupling

In order to explore the concrete durability of salt mineral fiber doped panels under the coupled action of freezing, panel concrete of different fiber types (polypropylene, polyacrylonitrile, steel fiber) under different dosages in different chlorine salt concentrations (2.0%, 3.5%, 5.0%) were tested in the freeze-thaw cycles, and the specimens were then inspected using a scanning electron microscope (SEM) after the freeze-thaw test. The results show that with the increase of salt freezing cycles the mass loss rate of the concrete specimens first decreased and then increased, while the compressive strength continued to decrease. The chlorine concentration had a great influence on the salt freezing coupling effect, among which the mass loss rate was the highest and the compressive strength decreased the fastest when the chlorine concentration was 3.5%. Different types of fiber could effectively enhance the salt freezing resistance of concrete. When the content of polypropylene and polyacrylonitrile fiber was 1.0 kg/m³, and the content of steel fiber was 70 kg/m³, the increase of mass loss rate of the specimens slowed down, so did the decrease of the compressive strength. So the salt freezing resistance performance of the specimens is satisfactory under these conditions.