The ingress of chloride ions is a serious threat for concrete structures. Superabsorbent polymers (SAPs) are interesting additions to cementitious systems due to their property of absorbing water during mixing and releasing it at a later time to provide internal curing, thereby reducing shrinkage and promoting durability. In addition, SAPs can improve the regain in impermeability of cracks by swelling and blocking the crack and promoting autogenous healing. The current study investigates the influence of the addition of SAPs without additional mixing water to the chloride ingress in cracked mortar via diffusion and quasi-steady-state migration testing. Filtration tests showed that the charge-screening effect in a NaCl solution is more dominant than for cement filtrate solution during swelling of SAPs. After wet/dry cycling for a month, subsequent chloride diffusion tests with 2 and 6 weeks of exposure showed that the addition of SAPs improved the performance with respect to a reference mix with the same total water-to-cement ratio. A reference mix with the same effective water-to-cement ratio as the SAP mix had a comparable performance to the SAP mix. One set of chloride diffusion experiments showed that the SAP mix was the only one successfully preventing chloride ingress into the deepest zone of the crack. The superior performance of the series with SAPs was also confirmed by migration testing where cracked and healed specimens obtained a migration coefficient which was only 12 % higher than uncracked specimens.

中文翻译：

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通过氯离子扩散和准稳态迁移试验测量高吸水性聚合物对砂浆氯离子侵入的影响


氯离子的进入对混凝土结构构成严重威胁。超吸水性聚合物 (SAP) 是水泥体系中有趣的添加物，因为它们具有在混合过程中吸收水并在稍后释放水以提供内部固化的特性，从而减少收缩并提高耐久性。此外，SAPs还可以通过膨胀、堵塞裂缝、促进自愈合来提高裂缝的抗渗回潮率。目前的研究通过扩散和准稳态迁移测试研究了在不额外搅拌水的情况下添加 SAP 对裂纹砂浆中氯化物进入的影响。过滤测试表明，在 SAP 膨胀过程中，氯化钠溶液中的电荷屏蔽效应比水泥滤液溶液中的电荷屏蔽效应更显着。湿/干循环一个月后，随后暴露 2 周和 6 周的氯离子扩散测试表明，相对于具有相同总水灰比的参考混合物，添加 SAP 改善了性能。与 SAP 混合物具有相同有效水灰比的参考混合物具有与 SAP 混合物相当的性能。一组氯离子扩散实验表明，SAP 混合物是唯一能成功防止氯离子进入裂缝最深区域的混合物。迁移测试也证实了该系列 SAP 的优越性能，其中裂纹和愈合的样本的迁移系数仅比未裂纹样本高 12%。