Early hydration of C2S doped with combination of S and Li
Early hydration of C2S doped with combination of S and Li
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DOI：
10.1007/s42452-020-2188-3
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发表时间：
2020-03-01
影响因子：
2.6
通讯作者：
Ludwig, H-M
中科院分区：
文献类型：
--
作者：
Bohac, M.;Stanek, T.;Ludwig, H-M
低能耗水泥的生产将节省能源，减少二氧化碳排放，这与减少燃料和高品位石灰石作为原材料的消耗有关。富贝利特熟料通过掺入S和Li的组合得到反应性更好的熟料，有可能成为波特兰水泥熟料的低能替代品之一。本文介绍了掺杂贝利石的制备，并对其早期水化和反应性进行了研究。采用高温固相合成方法，在实验室制备了富贝利特熟料。采用纯物质制备生料和熟料。采用等温量热法监测水泥浆体早期水化热流发展，采用原位x射线衍射和热重热分析（TGA/DTA）监测物相组成变化，采用SEM-SE监测水泥浆体微观结构。在给定时间，热流放热与定量相组成相关。与C3S水化有关的主放热峰的强度和位置随Li含量的增加而变化。S或S- Li复合掺杂C2S可显著提高富C2S水泥的反应性。C-S-H产物的形成是一个连续的过程，在前6 h主要依靠C3S，然后有β - c(2)5的缓慢反应支持。C(2)5的反应性受其他熟料相水化时间的影响。在TGA/DTA上检测到的两代波特兰岩形成为双吸热，可归因于C3S和β - c(2)5的水化作用。
Production of low-energy cements would result in energy saving and lower CO2 emissions related to reduced consumption of fuel and high-grade limestone as a raw material. Belite rich clinker, made more reactive by doping with combination of S and Li, could possibly be one of the low-energy alternatives for Portland cement clinker. Paper describes the preparation of doped belite and deals with its early hydration and reactivity. Belite rich clinkers were prepared in laboratory in high-temperature solid state synthesis. Pure substances were used for the preparation of raw meal and clinker. Early hydration heat flow development of cement pastes was monitored by isothermal calorimetry, changes in phase composition by "in situ" X-ray diffraction and TGA/DTA and microstructure by SEM-SE. Heat flow exotherms were correlated with quantified phase composition at given time. Intensity and position of main exothermic peak related to hydration of C3S is changing with increasing Li content. Doping of the C2S by the S or the combination of S and Li significantly increases the reactivity of the C2S-rich cement. The formation of C-S-H products is a continuous process that depends mainly on C3S during first 6 h and then is supported by slow reaction of beta-C(2)5. The reactivity of C(2)5 is affected by the timing of the hydration of other clinker phases. Two generations of portlandite formation detectable as a double endotherm on TGA/DTA can be attributed to hydration of C3S and beta-C(2)5.