Drawing inspiration from the design of Metal-Organic Frameworks (MOFs), this study developed Calcium Silicate Hydrate (C–S–H) gels-Organic Frameworks (COFs), as a novel internal curing agent for cement-based materials, through coordination bond self-assembly reaction. Compared with conventional superabsorbent polymers (SAP), the developed COFs were endowed with equivalent autogenous shrinkage mitigation ability but higher internal curing efficiency to cement paste. More importantly, the addition of COFs enhanced the compressive strength of mortar by 7 %–32 % due to the better volume stability of COFs and their stronger interface with cement matrix. Besides, the hydration degree of cement paste was accelerated by incorporating COFs owing to the seeding effect of C–S–H gels in COFs. In summary, the so-prepared COFs not only showed significantly improved performance than conventional SAP as internal curing agent, but also brought new insights into the design of organic-inorganic composites with tunable pore structure through coordination bonds self-assembly.

中文翻译：

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MOF结构启发的介孔复合材料作为内部固化剂增强水泥材料


本研究从金属有机框架（MOF）的设计中汲取灵感，通过配位键开发了硅酸钙水合物（C-S-H）凝胶-有机框架（COF）作为水泥基材料的新型内固化剂自组装反应。与传统的高吸水性聚合物（SAP）相比，所开发的COF具有同等的自收缩缓解能力，但对水泥浆体具有更高的内部固化效率。更重要的是，由于COF更好的体积稳定性及其与水泥基体更强的界面，COF的添加使砂浆的抗压强度提高了7%–32%。此外，由于COF中C-S-H凝胶的晶种效应，掺入COF加速了水泥浆的水化程度。综上所述，所制备的COF不仅比传统SAP作为内固化剂的性能显着提高，而且为通过配位键自组装调节孔结构的有机-无机复合材料的设计带来了新的见解。