The Interfacial Transition Zone (ITZ) in concrete is considered to be the weakest region of the mechanical properties of concrete, owing to the prevalence of microcracks induced by various external factors. These microcracks facilitate the ingress of corrosive solution into the ITZ through pores or crevices, ultimately impacting its mechanical integrity. This study aims to investigate the effects of different erosive environments on the mechanical properties of concrete ITZ and to analyze the intrinsic weakening mechanism via molecular dynamics simulations. The effects of different water contents and different ionic solutions are individually discussed in this study. Simulation results demonstrate a distinct trend in the mechanical properties of ITZ, exhibiting an initial increase followed by a decrease with the rise of water content under various conditions. Moreover, the magnitude of the mechanical properties of ITZ exhibits a hierarchy under different ionic solution conditions, ranked as follows: dry >10 wt% NaSO+NaCl >5 wt% NaSO > 5 wt% NaCl >5 wt% NaSO+NaCl > HO. The mechanical properties of ITZ are significantly influenced by its internal chemical bonds, which are susceptible to erosion from the infiltrating solution, resulting in the rupture of original chemical bonds and consequent reduction in ITZ's mechanical strength.

中文翻译：

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揭示侵蚀环境下混凝土界面过渡区的脆弱性：分子动力学研究


由于各种外部因素引起的微裂纹的普遍存在，混凝土中的界面过渡区（ITZ）被认为是混凝土力学性能最薄弱的区域。这些微裂纹有利于腐蚀性溶液通过孔隙或缝隙进入 ITZ，最终影响其机械完整性。本研究旨在研究不同侵蚀环境对混凝土ITZ力学性能的影响，并通过分子动力学模拟分析其内在弱化机制。本研究分别讨论了不同含水量和不同离子溶液的影响。模拟结果表明，ITZ 的机械性能呈现出明显的趋势，在各种条件下，随着含水量的增加，ITZ 的机械性能呈现先增加后减少的趋势。此外，ITZ的机械性能大小在不同离子溶液条件下呈现出层次结构，排序如下：干燥> 10 wt% NaSO + NaCl > 5 wt% NaSO > 5 wt% NaCl > 5 wt% NaSO + NaCl > H2O 。 ITZ的机械性能很大程度上受到其内部化学键的影响，这些化学键很容易受到渗透溶液的侵蚀，导致原有化学键断裂，从而降低ITZ的机械强度。