Early hydration of calcium sulfoaluminate cement through electrical resistivity measurement and microstructure investigations
Early hydration of calcium sulfoaluminate cement through electrical resistivity measurement and microstructure investigations
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通过电阻率测量和微观结构研究硫铝酸钙水泥的早期水化
DOI：
10.1016/j.conbuildmat.2010.09.042
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发表时间：
2011-04-01
影响因子：
7.4
通讯作者：
Li, Guowei
中科院分区：
文献类型：
--
作者：
Liao, Yishun;Wei, Xiaosheng;Li, Guowei
用非接触式电阻率仪测量了不同水灰比(W/C)的硫铝酸钙(CSA)水泥浆体1440min(或24 h)的电阻率。混合后的电阻率-时间曲线略有下降，然后在凝结时间附近急剧增加，然后出现两个峰值，最后以很低的速度发展到1440min。在水化初期(初凝时间之前)，孔隙率对CSA水泥浆体的电阻率发展起主导作用，而在后期(第二个峰值之后)，离子浓度起主导作用。电阻率-时间曲线显示了钙矾石在CSA水化体系中形成并转化为一硫酸盐的过程，这一点得到了扫描电子显微镜和X射线衍射仪的证实。CSA水泥体系水化过程中的高温和石膏不足导致钙矾石在第一个峰分解，而在第二个峰由于石膏的缺乏而分解。1h的水胶比与电阻率呈负相关，24h呈正相关，不同水灰比的抗压强度与24h的电阻率呈负相关。(C)2010爱思唯尔有限公司。保留所有权利。
The electrical resistivities of the calcium sulfoaluminate (CSA) cement pastes at different water to cement (W/C) ratios, over a period of 1440 min (or 24 h) were measured by a non-contacting electrical resistivity apparatus. The electrical resistivity-time curve decreased slightly after mixing, and then increased sharply around the setting time, followed by two peaks, and finally developed at a very low rate up to 1440 min. The porosity plays a dominant role in the electrical resistivity development of the CSA cement paste in the earlier period of hydration (before the initial setting time), while the ion concentration plays a major role at the later period (after the second peak). The electrical resistivity-time curve demonstrates the process of ettringite formation and transformation to monosulfate in the CSA hydration system, and this is confirmed by the SEM and XRD observations. The high temperature and the insufficiency of gypsum in the CSA cement system during hydration result in the decomposition of ettringite at the first peak, while at the second peak the decomposition of ettringite is due to the lack of gypsum. The relationship between W/C and electrical resistivity at 1 h follows a negative trend but a positive trend is observed at 24 h. The relationship between the compressive strength and the electrical resistivity at 24 h for the different W/C ratios follows a negative relationship. (C) 2010 Elsevier Ltd. All rights reserved.