A hydration study of various calcium sulfoaluminate cements
A hydration study of various calcium sulfoaluminate cements
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DOI：
10.1016/j.cemconcomp.2014.07.002
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发表时间：
2014-10-01
影响因子：
10.5
通讯作者：
Monteiro, P. J. M.
中科院分区：
文献类型：
--
作者：
Telesca, A.;Marroccoli, M.;Monteiro, P. J. M.
本文研究了五种硫铝酸钙水泥和一种三元混合物（包括普通波特兰水泥）的水化过程和微观结构特征。采用差热-热重分析（DTA-TG）、压汞法（MIP）、扫描电镜（SEM）和膨胀收缩试验对浆体进行了研究。DTA-TG分析证实了涉及CSA熟料主要成分三铝硫酸四钙的水合反应的作用，其产生（i）当与石灰和硫酸钙结合时的钙钒石，（ii）在仅硫酸钙存在下的钙钒石和氢氧化铝，以及（iii）在不存在石灰和硫酸钙的情况下的单硫酸盐和氢氧化铝。MIP和SEM能够区分膨胀（三元混合物和CSA水泥含有50%石膏）和非膨胀水泥。膨胀水泥浆体具有（i）接近单峰的孔径分布向更高的半径移动，以及（ii）在固化的第一天，钙矾石晶体的尺寸更小。在含有50%石膏的CSA水泥的硬化膏的SEM图像中，观察到星状钙矾石簇。(c)2014爱思唯尔有限公司版权所有。
The present work studies the hydration process and microstructural features of five calcium sulfoaluminate (CSA) cements and a ternary mixture including also ordinary Portland cement (OPC). The pastes were studied with simultaneous differential thermal-thermogravimetric (DTA-TG) analysis, mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and expansion/shrinkage tests. The DTA-TG analysis confirmed the role of the hydration reactions involving the main CSA clinker constituent, tetracalcium trialuminate sulfate, which produced (i) ettringite when combined with lime and calcium sulfate, (ii) ettringite and aluminum hydroxide in the presence of calcium sulfate alone, and (iii) monosulfate and aluminum hydroxide in the absence of both lime and calcium sulfate. The MIP and SEM were able to discriminate between expansive (ternary mixture and CSA cement containing 50% gypsum) and non-expansive cements. Expansive cement pastes had (i) a nearly unimodal pore size distribution shifted toward higher radii and (ii) ettringite crystals smaller in size during the first day of curing. In a SEM image of a hardened paste of the CSA cement containing 50% gypsum, a stellate ettringite cluster was observed. (c) 2014 Elsevier Ltd. All rights reserved.