Nano-Structural Change of C(N)-A-S-H Gel in Alkali-Activated Slag Pastes Subjected to Wetting-Drying Cyclic Sulphate Attack

被引：0
|
作者：
Zhu X. [1 ]
Li Q. [2 ]
Kang X. [3 ]
Deng J. [2 ]
Yang K. [2 ]
机构：
[1] School of Civil Engineering, University of Leeds, Leeds
[2] College of Materials Science and Engineering, Chongqing University, Chongqing
[3] Department of Civil Engineering, The University of Hong Kong, Hong Kong
来源：
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | 2021年 / 49卷 / 11期
关键词：
Alkali-activated slag cement; Attack; Gel; Silicon oxide tetrahedron; Structural change; Sulphate; Wetting-drying cycle;
D O I：
10.14062/j.issn.0454-5648.20210038
中图分类号：
学科分类号：
摘要：
Nano-structural change of calcium(sodium) aluminium silicate hydrates ( C(N)-A-S-H) gel in alkali-activated slag (AAS) mortars after wetting-drying cyclic attack in 5 % (mass fraction,the same below) and 10% sulphate solutions was investigated. The structural and compositional changes of aluminosilicate chains in the main binding phases (C(N)-A-S-H) in AAS mortars were analyzed by Fourier-transform infrared spectroscopy, thermogravimetry-differential scanning calorimetry, 29Si magic angle spinning nuclear magnetic resonance, backscattered scanning electron microscopy and transmission electron microscopy-energy dispersive X-ray spectroscopy. The results show that the sulphate attack increases the degree of reaction of ground granulated blast-furnace slag regardless of sulphate salt type. The main corrosion products in MgSO4 solutions are gypsum, which is not detected in the samples subjected to Na2SO4 solutions. The C(N)-A-S-H with longer chains prefers to be attacked in MgSO4 solutions, whilst the end-members of the chains or short chains of C(N)-A-S-H are broken in Na2SO4 solutions. The C(N)-A-S-H after cyclic water attack is a mixture of tobermorite/jennite dimer to undecamer (T/J2-T/J11), while the Na2SO4 solutions attack results in the destroy of shorter chains and the increase of protonation (or Na-balanced ratio), thus forming a new C(N)-A-S-H gel. © 2021, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.
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页码：2529 / 2537
页数：8
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