Layered double hydroxide (LDH) is reported to improve the durability of concretes, primarily due to its ability to exchange anionic species, including chloride, which is implicated in corrosion-driven durability issues. However, there is no comprehensive study investigating the effect of LDH on the properties of different cement systems at both early and mature ages. In this study, the early age and mature age properties of Portland cement (OPC) and calcium sulfoaluminate (CSA) cement pastes seeded with submicron-sized calcium aluminum-NO LDH (CaAl-NO LDH) were investigated. The effects of the 1–5% dosage of LDH on the hydration of both cement systems were characterized by rheology, isothermal calorimetry, porosimetry, compressive strength tests, thermogravimetric analysis, and x-ray diffraction. Time-dependent rheology results indicate that CaAl-NO LDH seeding enhanced the buildability of cement pastes, as evidenced by increased plasticity loss, hardening, and yield stress. While LDH seeding accelerated hydration kinetics for both CSA and OPC pastes, interestingly, the OPC exhibited reduced heat release, suggesting potential applications of LDH as heat sink in various areas, including building in hot climates, reducing heat and crack-propensity in mass concrete placements, and 3D-printed OPC-based concretes. Although LDH slightly decreased compressive strengths at both 1d and 28d, its primary role was to expedite the hydration process without enhancing the microstructure or strength of the final product.

中文翻译：

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亚微米 CaAl-NO3 LDH 颗粒对硅酸盐水泥和硫铝酸盐水泥浆体水化和性能的影响

据报道，层状双氢氧化物（LDH）可以提高混凝土的耐久性，主要是因为它能够交换阴离子物质，包括氯化物，而氯化物与腐蚀驱动的耐久性问题有关。然而，目前还没有全面的研究调查 LDH 对不同水泥体系在早期和成熟阶段性能的影响。在这项研究中，研究了含有亚微米级钙铝-NO LDH（CaAl-NO LDH）的波特兰水泥（OPC）和硫铝酸钙（CSA）水泥浆体的早期和熟龄特性。通过流变学、等温量热法、孔隙率测定法、抗压强度测试、热重分析和 X 射线衍射来表征 1-5% LDH 用量对两种水泥体系水化的影响。随时间变化的流变学结果表明，CaAl-NO LDH 晶种增强了水泥浆体的可施工性，塑性损失、硬化和屈服应力的增加证明了这一点。虽然 LDH 晶种加速了 CSA 和 OPC 浆料的水化动力学，但有趣的是，OPC 表现出减少的热量释放，这表明 LDH 作为散热器在各个领域的潜在应用，包括在炎热气候下的建筑、减少大体积混凝土浇筑中的热量和裂缝倾向，以及 3D 打印的 OPC 混凝土。尽管 LDH 在 1 天和 28 天时均略微降低了抗压强度，但其主要作用是加速水合过程，而不增强最终产品的微观结构或强度。