Abstract: Fiber-reinforced concrete was prepared using seawater and sea sand, and the erosion resistance of concrete under freeze-thaw cycles coupled with sulfate and its mechanism were investigated using concrete prepared from ordinary seawater and sea sand as a comparison. Salt freezing resistance was assessed by concrete appearance and morphology, compressive strength, and mass loss rate and micro-morphological features to obtain the optimum fiber mixing ratio. The results showed that the appropriate amount of fiber could improve the compressive strength of seawater and sea sand concrete, reduce the mass loss, and effectively improve the salt-freeze corrosion resistance of concrete. In the 50 coupling tests, the combination of 0.1% polypropylene fiber and 0.2% basalt fiber had the best effect. At this time, the compressive strength was 13.3% higher than that of ordinary seawater and sea sand concrete, and the mass loss rate was 22.4% lower than that of ordinary seawater and sea sand concrete, which made the salt-freeze erosion resistance of the seawater and sea sand concrete reach the best level.

Key words: seawater and sea sand concrete, sulfate erosion, freeze-thaw cycle, fiber reinforcement, microscopic mechanism

摘要： 使用海水与海砂制备纤维增强混凝土,并与普通海水海砂制备的混凝土作对比,研究了冻融循环与硫酸盐耦合作用下混凝土的抗侵蚀性能及其机理。通过混凝土外观形貌、抗压强度、质量损失率和微观形貌特征,评估抗盐冻性能,得到最佳纤维掺量的配合比。结果表明:适量掺加纤维能够提高海水海砂混凝土的抗压强度,降低质量损失,有效提升混凝土的抗盐冻侵蚀性能。在50次耦合试验中,0.1%聚丙烯纤维与0.2%玄武岩纤维的组合掺量效果最佳,此时抗压强度较普通海水海砂混凝土增加了13.3%,质量损失率较普通海水海砂混凝土减少了22.4%,使得海水海砂混凝土的抗盐冻侵蚀性能达到最佳水平。

关键词: 海水海砂混凝土, 硫酸盐侵蚀, 冻融循环, 纤维增强, 微观机理