Calcium leaching from cementitious materials in contact with bentonite in nuclear waste repositories can alter the functionality of an engineered barrier system. In this study, we contribute to the fundamental understanding of calcite precipitation at cement–bentonite interfaces by adding carbonate to bentonite. In addition, we accelerate the transport of charged reactants towards the interface using an electrochemical migration method. The carbonate admixture successfully promotes calcite precipitation at the surface of cement paste. The analysis also revealed that the amount of precipitated calcite is not simply correlated to the amount of added carbonate or the applied electrical potential. Experiments in which bentonite pore water contains high initial contents of carbonate exhibit rapid calcite precipitation in a very narrow region at the cement–bentonite interface, resulting in pore clogging. This is the second of two papers; the system evolution without an electrical gradient was discussed in the first paper. This paper is the extended version in English from the authors’ previous works [Watanabe and Nakarai, (2008). “Effect of NaHCO₃ in bentonite on calcium leaching from cementitious material.” Proc. of the JCI, 30(1), 717-722. Nakarai, et al., (2010). “Effect of carbonate mixing into bentonite on calcium leaching of cementitious material.” Proc. of the JCI, 32(1), 713-718. (in Japanese)]

在与核废料库中的膨润土接触时，从胶结材料中浸出的钙会改变工程屏障系统的功能。在这项研究中，我们通过向膨润土中添加碳酸盐来促进对方解石在水泥-膨润土界面上沉淀的基本理解。此外，我们使用电化学迁移方法来加速带电反应物向界面的传输。碳酸盐混合物成功地促进了方解石在水泥浆表面的沉淀。分析还表明，沉淀的方解石的数量并不简单地与碳酸盐的添加量或施加的电势相关。膨润土孔隙水中的碳酸盐含量较高的实验表明，方解石在水泥-膨润土界面的非常狭窄的区域内迅速析出，导致孔隙堵塞。这是两篇论文的第二篇；在第一篇论文中讨论了没有电梯度的系统演化。本文是作者先前作品的英文扩展版[Watanabe and Nakarai，（2008年）。“碳酸氢钠的影响从胶结材料中浸出钙时，膨润土中含有_3种。” 程序。JCI，30（1），717-722。Nakarai等人，（2010年）。“碳酸盐混入膨润土中对水泥质材料钙浸出的影响。” 程序。JCI，32（1），713-718。（日语）