单掺和混掺纤维面板混凝土抗盐冻耐久性试验研究

为了研究盐冻作用下掺纤维面板混凝土耐久性的问题,将钢纤维、聚丙烯纤维、聚丙烯腈纤维、聚丙烯-钢纤维、聚丙烯腈-钢纤维和聚丙烯-聚丙烯腈纤维掺入面板混凝土中,在质量分数为3.5%的氯盐浓度下进行冻融循环试验,并对盐冻循环后的试件开展电镜扫描。研究表明:掺纤维面板混凝土的质量损失率随盐冻循环次数增加呈现先减小再增大的趋势,相对动弹性模量和抗压强度则持续减小;单掺钢纤维面板混凝土抗盐冻性能最优,其次是混掺钢纤维面板混凝土,再次是混掺聚丙烯纤维面板混凝土,最差的是单掺聚丙烯纤维面板混凝土,但均优于普通面板混凝土抗盐冻性能。电镜扫描微观结果有效验证了单掺和混掺纤维对面板混凝土抗盐冻性能的作用效果。

Experimental study on salt-freezing durability of single and mixed fiber-doped panel concrete

In order to explore the concrete durability of fiber-doped panels under the action of salt-freezing, different fibers (steel fiber, polypropylene fiber, polyacrylonitrile fiber, polypropylene-steel fiber, polyacrylonitrile-steel fiber and polypropylene-polyacrylonitrile fiber) were doped in the panel concrete, which underwent freeze-thaw cycling test under the chlorine salt concentration of 3.5%. After the test, the specimens were inspected using a scanning electron microscope (SEM). The study found that as the number of salt-freezing cycles increased, the mass loss of the concrete specimens first decreased and then increased, whereas the relative dynamic elastic modulus and compressive strength kept decreasing. The salt-freezing resistance of panel concrete doped with single steel fiber was the best, followed by the panel concrete doped with polypropylene-steel fiber and polyacrylonitrile-steel fiber, and then polypropylene-polyacrylonitrile fiber, single polypropylene fiber-doped panel concrete performed the poorest; however they were all better than ordinary panel concrete. The microscopic test results of SEM verified the improving effect of single and mixed fibers on the salt-freezing resistance of panel concrete.