This study investigated the coupled effect of calcium leaching and chloride erosion on concrete subjected to hydraulic pressure by combining experiments and numerical simulations. Several tests including titration, pH, XRD, TG, MIP, and SEM-EDS were employed to analyze chloride concentration, pH value, solid phase compositions, and microstructure of concrete under hydraulic pressure. Concurrently, a model based on the physicochemical interactions between the pore solution and the hydration products was constructed to elucidate the process of calcium leaching and multi-ion transport. The experimental and simulation results reveal that hydraulic pressure accelerates calcium leaching in concrete, leading to a maximum porosity that reaches 1.5 times the initial porosity after a year. In addition, both the pH value and chloride binding capacity in the zone close to the exposure surface decrease. The enrichment of Ca2+ and OH− occurs at a specific depth within concrete during the calcium leaching process, and over time, this enrichment effect grows increasingly significant. Along the depth within the concrete, a transient increase in chloride binding capacity can be observed, which can be attributed to OH− and Ca2+ enrichment.

中文翻译：

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水压下混凝土中钙浸出与氯化物输运耦合效应的实验与模拟


本研究通过结合实验和数值模拟，研究了钙浸出和氯化物侵蚀对水压混凝土的耦合效应。采用滴定、pH、XRD、TG、MIP 和 SEM-EDS 等多项测试来分析液压下混凝土的氯化物浓度、pH 值、固相组成和微观结构。同时，构建了一个基于孔隙溶液和水合产物之间物理化学相互作用的模型，以阐明钙浸出和多离子传输的过程。实验和仿真结果表明，液压加速了混凝土中的钙浸出，导致一年后最大孔隙率达到初始孔隙率的 1.5 倍。此外，靠近暴露表面的区域的 pH 值和氯结合载量都会降低。在钙浸出过程中，Ca2+ 和 OH− 的富集发生在混凝土内的特定深度，随着时间的推移，这种富集效应变得越来越显着。沿着混凝土内的深度，可以观察到氯化物结合载量的瞬时增加，这可归因于 OH− 和 Ca2+ 富集。