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
相关论文
共 20 条
  • [11] KOCABA V, GALLUCCI E, SCRIVENER K L., Methods for determination of degree of reaction of slag in blended cement pastes, Cem Concr Res, 42, 3, pp. 511-525, (2012)
  • [12] KANG X, ZHU X, LIU J, Et al., Hydration of C<sub>3</sub>A/gypsum composites in the presence of graphene oxide, Mater Today Commun, 23, (2020)
  • [13] TAJUELO RODRIGUEZ E, GARBEV K, MERZ D, Et al., Thermal stability of C-S-H phases and applicability of Richardson and Groves' and Richardson C-(A)-S-H(I) models to synthetic C-S-H, Cem Concr Res, 93, pp. 45-56, (2017)
  • [14] TREVOR L H, CLAIRE M M, TIMOTHY G J J, Et al., Determining cement composition by Fourier transform infrared spectroscoy, Adv Cem Based Mater, 2, pp. 91-104, (1995)
  • [15] FROST R L, KLOPROGGE J T., Infrared emission spectroscopic study of brucite, Spectroc Acta Pt A-Molec Biomolec, 55, 11, pp. 2195-2205, (1999)
  • [16] LODEIRO I G, MACPHEE D E, PALOMO A, Et al., Effect of alkalis on fresh C-S-H gels FTIR analysis, Cem Concr Res, 39, pp. 147-153, (2009)
  • [17] RICHARDSON I G, GIRO A V, TAYLOR R, Et al., Hydration of water- and alkali-activated white Portland cement pastes and blends with low-calcium pulverized fuel ash, Cem Concr Res, 83, pp. 1-18, (2016)
  • [18] GROVES G W, BROUGH A, RICHARDSON I G, Et al., Progressive changes in the structure of hardened C3S cement pastes due to carbonation, J Am Ceram Soc, 74, 11, pp. 2891-2896, (1991)
  • [19] SAOUT G L, HAHA M B, WINNEFELD F, Et al., Hydration degree of alkali-activated slags: A <sup>29</sup>Si NMR study, J Am Ceram Soc, 94, 12, pp. 4541-4547, (2011)
  • [20] BERNAL S A, PROVIS J L, WALKLEY B, Et al., Gel nanostructure in alkali-activated binders based on slag and fly ash, and effects of accelerated carbonation, Cem Concr Res, 53, pp. 127-144, (2013)
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