Carbonation of calcium silicate (CS) minerals to produce hardened construction materials has attracted increasing interest, but the efficiency of conventional CS minerals is low. This study prepared a highly reactive β-CS derived from a C-S-H precursor through hydrothermal synthesis. The potential CO uptake ability, product compositions, microstructural characteristics, and carbonation mechanisms of the hydrothermal β-CS were investigated. The results showed that the hydrothermal β-CS achieved 3.7 times higher carbonation efficiency compared to the reference β-CS prepared by traditional calcination and reached a carbonation degree of 56.1 % within 10 min. Its high reactivity was attributed to large specific surface area, unique thin lath structure, and fine grain size. The novel type of C-S-H produced, special thin lath structure evolution and sufficient ACC led to an almost complete carbonation degree of hydrothermal β-CS. The developed carbonation process could be used to valorize recycled concrete waste which contains a large amount of C-S-H.

中文翻译：

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高碳酸化效率硅酸钙（β-C2S）的开发：相演化、微观结构和碳酸化机制


硅酸钙 (CS) 矿物的碳化生产硬化建筑材料引起了越来越多的兴趣，但传统 CS 矿物的效率较低。本研究通过水热合成从 C-S-H 前体制备了高反应活性的 β-CS。研究了水热β-CS的潜在CO吸收能力、产物组成、微观结构特征和碳酸化机制。结果表明，与传统煅烧制备的参比β-CS相比，水热β-CS的碳酸化效率提高了3.7倍，并且在10 min内达到了56.1%的碳酸化度。其高反应活性归因于大的比表面积、独特的薄板条结构和细晶粒尺寸。所产生的新型C-S-H、特殊的薄板条结构演变和足够的ACC导致热液β-CS几乎完全碳化。所开发的碳化工艺可用于回收含有大量 C-S-H 的混凝土废料。