硫酸盐溶液干湿循环作用下玄武岩纤维混凝土强度演化模型

Strength evolution model of basalt fiber reinforced concrete under dry-wet cycles of sulfate solutions

开展不同质量分数硫酸盐溶液干湿循环作用下玄武岩纤维混凝土侵蚀试验、强度试验和微观测试,分析混凝土抗压、抗拉强度和细观结构演变规律,引入相对强度系数,建立玄武岩纤维混凝土强度演化模型,并应用于某输水渡槽结构受力特性分析.结果表明,在质量分数7%的硫酸钠溶液中,试件的相对强度系数随侵蚀周期单调递增,而在质量分数15%的硫酸钠溶液中则表现为先增后减.硫酸盐溶液干湿循环作用40次后,纤维增强效果逐渐突显.强度演化模型结果与试验值的平均相对误差最大值和均方根误差最大值分别为0.9840%和1.4703×10^(-2),决定系数最小值为0.9821,说明该模型可较好地描述硫酸钠溶液干湿循环作用下玄武岩纤维混凝土强度演化规律.相比于未掺纤维混凝土,在混凝土中掺入玄武岩纤维可有效减缓渡槽受硫酸盐溶液干湿循环侵蚀的劣化进程.

The erosion tests,strength tests and micro tests of basalt fiber reinforced concrete under dry-wet cycles of sulfate solutions with different concentrations were conducted to analyze the evolution laws of the compressive strength,tensile strength and microstructure of concrete specimens.The strength evolution models of basalt fiber concrete were proposed by introducing the relative strength coefficient and applied to the analysis of the mechanical characteristics of aqueduct.The results show that the relative strength coefficient of the specimen increases monotonically with the erosion cycle in the sodium sulfate solution with the mass fraction of 7%,while it first increases and then decreases in the sodium sulfate solution with the mass fraction of 15%.After 40 dry-wet cycles,the strengthening effect of the fiber is gradually prominent.The maximum values of the mean relative error and the root mean square error of the strength evolution model results and the experimental values are 0.9840%and 1.4703×10^(-2),respectively,and the minimum determination coefficient is 0.9821,indicating that this model can describe the strength evolution law of basalt fiber reinforced concrete under the dry-wet cycles of sodium sulfate solutions.Compared with concrete without fiber in aqueduct,basalt fiber can effectively slow down the deterioration process of aqueduct under dry-wet cycles of sulfate solutions.