Changes on the nanostructure of cementitius calcium silicate hydrates (C–S–H) induced by aqueous carbonation
Changes on the nanostructure of cementitius calcium silicate hydrates (C–S–H) induced by aqueous carbonation
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DOI：
10.1007/s10853-011-5852-6
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发表时间：
2011
影响因子：
4.5
通讯作者：
V. Morales-Flórez;N. Findling;F. Brunet
中科院分区：
文献类型：
--
作者：
V. Morales-Flórez;N. Findling;F. Brunet
使用 TEM、氮物理吸附和 SAXS 表征了水合水泥的主要粘结相、硅酸钙水合物 (C-S-H) 的纳米结构及其由于水碳酸化而导致的结构变化。合成的 C-S-H 已用于此目的。鉴定出两种不同的形态，类似于高密度和低密度 C-S-H 类型。当将样品置于 CO2 通量中时，低密度相完全碳酸化。还对碳酸化副产物碳酸钙和硅胶进行了鉴定和表征。硅胶的沉淀将比表面积从 95 增加到 132 m2/g，其结构由典型半径约为 5 nm 的颗粒形成，通过小角 X 射线散射观察到。此外，还报道了高密度C-S-H的抗碳化性能，并讨论了沉淀碳酸钙的钝化作用。最后，将结果与井下条件下实验碳化波特兰水泥观察到的碳化特征进行了比较。
The nanostructure of the main binding phase of the hydrated cements, the calcium silicate hydrates (C–S–H), and their structural changes due to aqueous carbonation have been characterized using TEM, nitrogen physisorption, and SAXS. Synthetic C–S–H has been used for this purpose. Two different morphologies were identified, similar to the high density and low density C–S–H types. When submitting the sample to a CO2flux, the low density phase was completely carbonated. The carbonation by-products, calcium carbonate, and silica gel were also identified and characterized. The precipitation of the silica gel increased the specific surface area from 95 to 132 m2/g, and its structure, formed by particles of ~5 nm typical radius, was observed by small angle X-ray scattering. In addition, the resistance of the high density C–S–H to carbonation is reported, and the passivating effect of the precipitated calcium carbonate is also discussed. Finally, the results have been compared with carbonation features observed in Portland cement carbonated experimentally at downhole conditions.