硫酸盐-氯盐环境下粉煤灰-水泥砂浆物相演变及定量分析

Phase Evolution and Quantitative Analysis of Fly Ash-Cement Mortar in Sulfate-Chloride Environment

为了分析硫酸盐-氯盐环境下的水泥基材料的物相演变规律,本工作粉煤灰-水泥砂浆为研究对象,开展腐蚀溶液中的长期浸泡实验,并通过QXRD、SEM、MIP微观测试,分析砂浆中氯离子和硫酸根离子的交互作用、物相演变规律以及微结构变化。结果表明:在硫酸盐-氯盐侵蚀前、中期,离子间竞争作用导致侵蚀产物含量降低,延缓了试件中氯盐和硫酸盐的侵蚀进程;侵蚀后期,试件中侵蚀产物累积造成孔结构劣化,导致更多离子进入其内部,加速氯盐和硫酸盐侵蚀进程,此时,氯盐的存在不能再延缓硫酸盐的侵蚀。

In order to investigate the phase evolution and characteristics of cement-based materials in sulfate-chloride environments,some fly ash(FA)-blended cement mortar specimens were taken as the research object to perform the long-term immersion experiments in sulfate and chloride solutions with different concentrations.By using QXRD、SEM、MIP measurements,the evolution of product phases and the change of microstructures as well as the interactions between chlorides and sulfates in FA-blended mortar were analyzed.Results show that,at the early and middle stages of solution immersion,the competitions between sulfates and chlorides can reduce the contents of their corrosion products,and it can slow down the process of sulfate and chloride attacks.Moreover,at the late stage of solution immersion,the continuous formation of corrosion pro-ducts can deteriorate the pore structure of FA-blended mortar,causing the penetration of more sulfates or chlorides into the specimens,and this can accelerate the process of chloride and sulfate attack,so the presence of chlorides in the solutions can no longer delay the sulfate attack on the FA-blended mortar.