29Si and 27Al high-resolution NMR characterization of calcium silicate hydrate phases in activated blast-furnace slag pastes
29Si and 27Al high-resolution NMR characterization of calcium silicate hydrate phases in activated blast-furnace slag pastes
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DOI：
10.1016/s0008-8846(01)00530-0
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发表时间：
2001-07-01
影响因子：
11.4
通讯作者：
Panepucci, H
中科院分区：
文献类型：
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作者：
Schneider, J;Cincotto, MA;Panepucci, H
在改善矿渣水泥力学性能的框架内，采用Si-29和Al-27高分辨核磁共振（NMR）技术，对一组28天龄期的矿渣水泥硬化浆体进行了9.4T的分析。通过核磁共振表征了不同活化和固化条件下C-S-H相的结构和组成差异。用不同碱度的化合物（硅酸钠、氢氧化钠、氢氧化钙和石膏）并在蒸汽和湿养护下进行矿渣的活化。通过核磁共振谱分析得到了表征水化反应程度、硅酸铝链聚合度和C-S-H中Al/Si比的参数。Si ~（29）-NMR谱表明，所有浆体中硅酸盐四面体的连接体均符合C-S-H的“dreier-chain”结构模型。在用硅酸钠和石膏/氢氧化钙混合物活化产生的糊剂中观察到C-S-H中铝硅酸盐基团的显著聚合度。蒸汽养护和较高的碱浓度促进了Al在C-S-H中的掺入。即使在低浓度的碱的情况下，通过蒸汽固化，也可以获得与在较高碱添加的情况下一样高的Al在C-S-H中的结合程度。(C)2001爱思唯尔科技有限公司版权所有。
Within the framework of improving mechanical properties of activated blast-furnace slag cements, a set of hardened pastes of 28 days age were analyzed by Si-29 and Al-27 high-resolution nuclear magnetic resonance (NMR) at 9.4 T. Structural and compositional differences among C-S-H phases obtained with different activation and curing conditions were characterized by NMR. Activation of the slag was done with compounds of different alkalinity (sodium silicate, sodium hydroxide, calcium hydroxide and gypsum), and under steam and wet curing. Parameters characterizing the extent of the hydration reaction, the polymerization degree of the aluminum-silicate chains and the Al/Si ratio in C-S-H were obtained from NMR spectra. Si-29-NMR spectra indicated that connectivites of silicate tetrahedra in all pastes are compatible with the "dreierkette" structural model of C-S-H. A substantial degree of polymerization of the aluminum-silicate groups in C-S-H was observed in pastes resulting from activation with sodium silicate and gypsum/calcium hydroxide blend. Steam curing and a higher alkali concentration enhanced the incorporation of Al in C-S-H. Even with low concentration of alkali, through steam curing it is possible to obtain a degree of incorporation of Al in C-S-H as high as in the case of higher alkali addition. (C) 2001 Elsevier Science Ltd. All rights reserved.