Abstract
The thermodynamic stability of sulfate ions on synthesized calcium aluminosilicate hydrate (C-A-S-H) microstructure with different Ca/Si ratios and Al/Si ratios was investigated by XRD, SEM-EDS, 29Si and 27Al nuclear magnetic resonance (NMR) and thermodynamic modeling. The results indicate that sulfate attack leads to both decalcification and dealumination for C-A-S-H gels, and the amount of corrosion products (gypsum and ettringite) decreased gradually with decreasing Ca/Si ratios of C-A-S-H. Sulfate ions can also promote the polymerization degree of C-A-S-H gels, improving its resistance to sulfate attack. Moreover, the 4-coordination aluminum (Al[4]) in C-A-S-H, 5-coordination aluminum (Al[5]), 6-ccordination aluminum (Al[6]) in TAH (third aluminum hydrate) and Al[6] in monosulfate or C-A-H (calcium aluminate hydrate) can be transformed into Al[6] in ettringite by sulfate attack. Furthermore, through thermodynamic calculation, the decrease of Ca/Si ratios and increase of Al/Si ratios can improve the thermodynamic stability of C-A-S-H gels under sulfate attack, which agrees well with the experiment results.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Taylor H F W. Cement Chemistry, 2nd ed[M]. London: Thomas Telford, 1997
Irassar E F, Bonavetti V L, Gonzalez M. Microstructural Study of Sulfate Attack on Ordinary and Limestone Portland Cements at Ambient Temperature[J]. Cem. Concr. Res., 2003, 33(1): 31–41
Kalousek G L. Crystal Chemistry of Hydrous Calcium Silicates: I. Substitution of Aluminum in Lattice of Tobermorite[J]. J. Am. Ceram. Soc., 1957, 40(3): 74–80
Richardson I G, Brough A R, Brydson R, et al. Location of Aluminum in Substituted Calcium Silicate Hydrate (C-S-H) Gels as Determined by 29Si and 27Al NMR and EELS[J]. J. Am. Ceram. Soc., 1993, 76(9): 2 285–2 288
Richardson I G. The Nature of CSH in Hardened Cements[J]. Cem. Concr. Res., 1999, 29(8): 1 131–1 147
Richardson I G. Tobermorite/Jennite and Tobermorite/Calcium Hydroxide Based Models for the Structure of CSH: Applicability to Hardened Pastes of Tricalcium Silicate, ß-dicalcium Silicate, Portland Cement, and Blends of Portland Cement with Blast-furnace Slag, Metakaolin, or Silica Fume[J]. Cem. Concr. Res., 2004, 34(9): 1 733–1 777
El-Hachem R, Rozière E, Grondin F, et al. New Procedure to Investigate External Sulphate Attack on Cementitious Materials[J]. Cem. Concr Compo., 2012, 34(3): 357–364
Lothenbach B, Bary B, Bescop P L, et al. Sulfate Ingress in Portland Cement[J]. Cem. Concr Res., 2010, 40(8): 1 211–1 225
Kunther W, Lothenbach B, Skibsted J. Influence of the Ca/Si Ratio of the C-S-H Phase on the Interaction with Sulfate Ions and Its Impact on the Ettringite Crystallization Pressure[J]. Cem. Concr Res., 2015, 69(1): 37–49
Lippmaa E, Maegi M, Samoson A, et al. Structural Studies of Silicates by Solid-state High-resolution 29Si NMR[J]. J. Am. Chem. Soc., 1980, 102: 4 889–4 893
Justnes H, Meland I, Bjoergum J O, et al. NMR-a Powerful Tool in Cement and Concrete Research[J]. Adv. Cem. Res., 1990, 3(11): 105–110
Sun G K, Young J F, Kirkpatrick R J. The Role of Al in C-S-H: NMR, XRD, and Compositional Results for Precipitated Samples[J]. Cem. Concr Res., 2006, 36(1): 18–29
Andersen M D, Jakobsen H J, Skibsted J. Incorporation of Aluminum in the Calcium Silicate Hydrate (C-S-H) of Hydrated Portland Cements: a High-field 27Al and 29Si MAS NMR Investigation[J]. Inorg. Chem., 2003, 42(7): 2 280–2 287
Grimmer A R. Structural Investigation of Calcium Silicates from 29Si Chemical Shift Measurements[M]. In: P Colombet, A-R Grimmer (Eds.). Application of NMR Spectroscopy to Cement Science, London: Gordon and Breach, 1994
Brough A R, Dobson C M, Richardson I G, et al. In Situ Solid-state NMR Studies of Ca3SiO5: Hydration at Room Temperature Using 29Si Enrichment[J]. J. Mater Sci., 1994, 29(15): 3 926–3 940
Hu C G, Hu S G, Ding Q J, et al. Effect of Curing Regime on Degree of Al3+ Substituting for Si4+ in C-S-H Gels of Hardened Portland Cement Pastes[J]. Journal of Wuhan University of Technology-Mater. Sci. Ed., 2014, 29(3): 546–552
Faucon P, Delagrave A, Petit J C, et al. Aluminum Incorporation in Calcium Silicate Hydrates (C-S-H) Depending on Their Ca/Si Ratio[J]. J. Phys. Chem., 1999, B103: 7 796–7 802
Renaudin G, Russias J, Leroux F, et al. Structural Characterization of C-S-H and C-A-S-H Samples-Part II: Local Environment Investigated by Spectroscopic Analyses[J]. J. Solid State Chem., 2009, 182(12): 3 320–3 329
Andersen M D, Jakobsen H J, Skibsted. A New Aluminium-hydrate Species in Hydrated Portland Cements Characterized by 27Al and 29Si MAS NMR Spectroscopy[J]. Cem. Concr Res., 2006, 36(1): 3–17
Thoenen T, Kulik D. Nagra/PSI Chemical Thermodynamic Database 01/01 for the GEMS-Selektor (V.2-PSI) Geochemical Modeling Code, PSI, Villigen[EB/OL]. http://les.web.psi.ch/software/GEMS-PSI/doc/pdf/TM-44-03-04-web.pdf, 2003
Author information
Authors and Affiliations
Corresponding author
Additional information
Funded by Anhui Key Laboratory of Advanced Building Materials, Anhui Jianzhu University (No. JZCL201602KF), Major State Basic Research Development Program of China (973 Program) (No. 2015CB655101), State Key Laboratory of High Performance Civil Engineering Materials (No. 2015CEM005), Natural Science Foundation of Hebei Province (No. E2016209283), Hubei Key Laboratory of Roadway Bridge and Structure Engineering (Wuhan University of Technology) (No. DQZDJJ201504)
Rights and permissions
About this article
Cite this article
Hu, C., Ding, Q., Wang, H. et al. Thermodynamic Stability of Sulfate Ions on Calcium Aluminosilicate Hydrate Microstructure. J. Wuhan Univ. Technol.-Mat. Sci. Edit. 34, 638–647 (2019). https://doi.org/10.1007/s11595-019-2098-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11595-019-2098-7