硫酸盐侵蚀环境下隧道衬砌混凝土的胶凝材料组分研究

Gel Material Component of Tunnel Lining Concrete under the Environment of Sulfate Attack

采用三因素四水平正交试验法设计了16组胶砂配合比,研究粉煤灰、矿渣粉、硅灰常见矿物掺合料种类及掺量对胶砂试件强度、抗硫酸盐侵蚀性能及微观结构的影响。结果表明:标准养护条件下,粉煤灰的掺入降低水泥基材料28 d龄期强度,且随着掺量的增加强度降低幅度增大。随矿渣粉掺量的增加,28 d龄期强度呈现先增大后减小的趋势,硅灰对水泥基材料28 d龄期强度的贡献率大于粉煤灰和矿渣粉。硫酸盐侵蚀环境下,不同胶凝体系的水泥基材料随干湿循环次数的增加,其抗折强度和抗压强度均呈现先增大后减小的趋势。与矿渣粉相比,粉煤灰和硅灰对改善水泥基材料抗硫酸盐侵蚀性能效果更为显著。

16 groups of gel-sand mix proportion are designed by adopting the orthogonal test of three factors and four levels,researching on the influence of mixing types and mixing amount of common mineral admixtures such as coal ash,slag powder,silicon ash on gel-sand test piece strength,sulfate resistance and microstructure.The result shows that under the standard curing condition,the strength of cement-based materials at 28 d age decreases with the addition of coal ash,and the strength decreases with the increase of the amount of coal ash.With the increase of slag powder,the 28 d strength increases first and then decreases.The contribution rate of silica fume to the 28 d strength of cement-based materials is greater than that of coal ash and slag powder.In the sulfate attack environment,the breaking strength and compressive strength of cement-based materials with different cementitious systems increases first and then decreases with the increase of the number of dry and wet cycles.Compared with slag powder,coal ash and silica fume are more remarkable in promoting the efficiency of sulfate resistance of cement-based materials.