水电能源科学

在盐湖、盐渍土水位变幅区，混凝土结构遭受硫酸盐侵蚀和干湿循环耦合作用，势必加速混凝土侵蚀劣化和性能衰退进程。在混凝土中掺入不同含量的玄武岩纤维，制备纤维增强混凝土试件，并进行硫酸盐干湿循环试验，分析了盐侵-干湿耦合作用下纤维混凝土质量和力学强度随不同纤维掺量的变化规律，并结合SEM观察微观结构形貌劣化演变。结果表明，低硫酸盐浓度下，质量和力学强度随干湿循环次数呈近似线性增加，而高浓度下，变化规律演变为先增后减的“抛物线”型；适量纤维的掺入可有效提高混凝土致密性，削弱硫酸盐侵蚀对混凝土性能劣化的影响；通过SEM分析，硫酸盐干湿作用下混凝土的腐蚀残余物主要为柱状钙矾石，伴有少许团簇状石膏晶体。

Under the fluctuation of water levels in salt lakes and saline soils, concrete structures are subjected to sulfate erosion and coupled effects of dry wet cycles, which inevitably accelerate the deterioration of concrete erosion and performance degradation. This article conducts sulfate erosion and dry wet cycle tests on basalt fiber-reinforced concrete, analyzes the changes in specimen quality damage and compressive strength with the number of dry wet cycles under different sulfate concentrations and fiber contents, and combines SEM to observe the deterioration of microstructure morphology. The results show that at low sulfate concentrations, the mass and compressive strength increased approximately linearly with the number of wet dry cycles, while at high concentrations, the change pattern evolved into a "parabolic" pattern of first increasing and then decreasing; The moderate addition of fibers can effectively improve the density of concrete and weaken the influence of sulfate corrosion on the deterioration of concrete performance. Through SEM analysis, the corrosion products under dry wet cycle sulfate erosion are mainly columnar ettringite and clustered gypsum crystals.