Skip to main content
Springer Nature Link
Log in

Aluminosilicate Gel Formation in Alkali-Activated Fly Ash: An NMR Spectroscopic Study

  • MISCELLANEOUS
  • Published:
Save article
View saved research
Coke and Chemistry Aims and scope Submit manuscript

Abstract

This study investigates the impact of a CO2-rich environment on the aluminosilicate gel in alkali-activated fly ash (AAAFA) using NMR spectroscopy. After 24 h of curing at 80°C, the AAAFA samples were exposed to a 10% ambient CO2 concentration. Highly reactive elements such as Na and Al fully reacted within the initial hours and remained unaffected by carbonation under high CO2 levels. However, Si, which reacts more slowly, exhibited distinct behaviour. Monomeric silicates rapidly polymerized despite the carbonated sample showing a lower overall reaction extent. This indicates the formation of a binding gel phase due to intense CO2 exposure, leading to an increased gel content in the carbonated sample. These findings enhance the understanding of aluminosilicate gel chemistry and behavior under elevated CO2 concentrations, providing insights into the long-term performance of alkali-activated materials in carbon-rich environments.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Subscribe and save

Springer+
from €37.37 /Month
  • Starting from 10 chapters or articles per month
  • Access and download chapters and articles from more than 300k books and 2,500 journals
  • Cancel anytime
View plans

Buy Now

Price includes VAT (India)

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1.
The alternative text for this image may have been generated using AI.
Fig. 1.
The alternative text for this image may have been generated using AI.
Fig. 2.
The alternative text for this image may have been generated using AI.
Fig. 3.
The alternative text for this image may have been generated using AI.
Fig. 4.
The alternative text for this image may have been generated using AI.

Similar content being viewed by others

Explore related subjects

Discover the latest articles, books and news in related subjects, suggested using machine learning.

DATA AVAILABILITY

Up on reasonable request the corresponding author will share the data created as well as analyses during this study.

REFERENCES

  1. Bernal, S.A., Provis, J.L., Walkley, B., San Nicolas, R., Gehman, J.D., Brice, D.G., Kilcullen, A.R., Duxson, P., and van Deventer, J.S.J., Gel nanostructure in alkali-activated binders based on slag and fly ash, and effects of accelerated carbonation, Cem. Concr. Res., 2013, vol. 53, pp. 127–144. https://doi.org/10.1016/j.cemconres.2013.06.007

    Article  CAS  Google Scholar 

  2. Roviello, G., Ricciotti, L., Ferone, C., Colangelo, F., Cioffi, R., and Tarallo, O., Synthesis and characterization of novel epoxy geopolymer hybrid composites, Materials, 2013, vol. 6, no. 9, pp. 3943–3962. https://doi.org/10.3390/ma6093943

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Roviello, G., Menna, C., Tarallo, O., Ricciotti, L., Ferone, C., Colangelo, F., Asprone, D., di Maggio, R., Cappelletto, E., Prota, A., and Cioffi, R., Preparation, structure and properties of hybrid materials based on geopolymers and polysiloxanes, Mater. Des., 2015, vol. 87, pp. 82–94. https://doi.org/10.1016/j.matdes.2015.08.006

    Article  CAS  Google Scholar 

  4. Palomo, Á., Alonso, S., Fernandez-Jiménez, A., Sobrados, I., and Sanz, J., Alkaline activation of fly ashes: NMR study of the reaction products, J. Am. Ceram. Soc., 2004, vol. 87, no. 6, pp. 1141–1145. https://doi.org/10.1111/j.1551-2916.2004.01141.x

    Article  CAS  Google Scholar 

  5. Fernández-Jiménez, A., Palomo, Á., Sobrados, I., and Sanz, J., The role played by the reactive alumina content in the alkaline activation of fly ashes, Microporous Mesoporous Mater., 2006, vol. 91, nos. 1–3, pp. 111–119. https://doi.org/10.1016/j.micromeso.2005.11.015

    Article  CAS  Google Scholar 

  6. Jang, J.G. and Lee, H.K., Effect of fly ash characteristics on delayed high-strength development of geopolymers, Constr. Build. Mater., 2016, vol. 102, pp. 260–269. https://doi.org/10.1016/j.conbuildmat.2015.10.172

    Article  CAS  Google Scholar 

  7. Jang, J.G., Lee, N.K., and Lee, H.K., Fresh and hardened properties of alkali-activated fly ash/slag pastes with superplasticizers, Constr. Build. Mater., 2014, vol. 50, pp. 169–176. https://doi.org/10.1016/j.conbuildmat.2013.09.048

    Article  Google Scholar 

  8. Fernández-Jimenez, A., de la Torre, A.G., Palomo, A., López-Olmo, G., Alonso, M.M., and Aranda, M.A.G., Quantitative determination of phases in the alkali activation of fly ash. Part I. Potential ash reactivity, Fuel, 2006, vol. 85, no. 5, pp. 625–634. https://doi.org/10.1016/j.fuel.2005.08.014

    Article  CAS  Google Scholar 

  9. Bernal, S.A. and Provis, J.L., Durability of alkali-activated materials: Progress and perspectives, J. Am. Ceram. Soc., 2014, vol. 97, no. 4, pp. 997–1008. https://doi.org/10.1111/jace.12831

    Article  CAS  Google Scholar 

  10. Criado, M., Palomo, A., and Fernández-Jiménez, A., Alkali activation of fly ashes. Part 1: Effect of curing conditions on the carbonation of the reaction products, Fuel, 2005, vol. 84, no. 16, pp. 2048–2054. https://doi.org/10.1016/j.fuel.2005.03.030

    Article  CAS  Google Scholar 

  11. Bernal, S.A., Provis, J.L., Brice, D.G., Kilcullen, A., Duxson, P., and Van Deventer, J.S.J., Accelerated carbonation testing of alkali-activated binders significantly underestimates service life: The role of pore solution chemistry, Cem. Concr. Res., 2012, vol. 42, no. 10, pp. 1317–1326. https://doi.org/10.1016/j.cemconres.2012.07.002

    Article  CAS  Google Scholar 

  12. Park, S.-M., Jang, J.-G., Kim, G.-M., and Lee, H.-K., Strength development of alkali-activated fly ash exposed to a carbon dioxide-rich environment at an early age, J. Korean Ceram. Soc., 2016, vol. 53, no. 1, pp. 18–23. https://doi.org/10.4191/kcers.2016.53.1.18

    Article  CAS  Google Scholar 

  13. Duxson, P., Provis, J.L., Lukey, G.C., Separovic, F., and Van Deventer, J.S.J., 29Si NMR study of structural ordering in aluminosilicate geopolymer gels, Langmuir, 2005, vol. 21, no. 7, pp. 3028–3036. https://doi.org/10.1021/la047336x

    Article  CAS  PubMed  Google Scholar 

  14. Jeon, D., Jun, Yu., Jeong, Ye., and Oh, J.E., Microstructural and strength improvements through the use of Na2CO3 in a cementless Ca(OH)2-activated Class F fly ash system, Cem. Concr. Res., 2015, vol. 67, pp. 215–225. https://doi.org/10.1016/j.cemconres.2014.10.001

    Article  CAS  Google Scholar 

  15. Mera, G., Tamayo, A., Nguyen, H., Sen, S., and Riedel, R., Nanodomain structure of carbon-rich silicon carbonitride polymer-derived ceramics, J. Am. Ceram. Soc., 2010, vol. 93, no. 4, pp. 1169–1175. https://doi.org/10.1111/j.1551-2916.2009.03558.x

    Article  CAS  Google Scholar 

  16. Kleebe, H.-J. and Blum, Yi.D., SiOC ceramic with high excess free carbon, J. Eur. Ceram. Soc., 2008, vol. 28, no. 5, pp. 1037–1042. https://doi.org/10.1016/j.jeurceramsoc.2007.09.024

    Article  CAS  Google Scholar 

  17. Mobasher, N., Bernal, S.A., and Provis, J.L., Structural evolution of an alkali sulfate activated slag cement, J. Nucl. Mater., 2016, vol. 468, pp. 97–104. https://doi.org/10.1016/j.jnucmat.2015.11.016

    Article  CAS  Google Scholar 

  18. Ban, T. and Okada, K., Analysis of local cation arrangement in mullite using 29Si magic-angle spinning nuclear magnetic resonance spectra, J. Am. Ceram. Soc., 1993, vol. 76, no. 10, pp. 2491–2496. https://doi.org/10.1111/j.1151-2916.1993.tb03971.x

    Article  CAS  Google Scholar 

  19. Rehak, P., Kunath-Fandrei, G., Losso, P., Hildmann, B., Schneider, H., and Jäeger, C., Study of the Al coordination in mullites with varying Al:Si ratio by 27Al NMR spectroscopy and X-ray diffraction, Am. Mineral., 1998, vol. 83, nos. 11–12_part_1, pp. 1266–1276. https://doi.org/10.2138/am-1998-11-1215

  20. Kohn, S.C., Brooker, R.A., and Dupree, R., 13C MAS NMR: A method for studying CO2 speciation in glasses, Geochim. Cosmochim. Acta, 1991, vol. 55, no. 12, pp. 3879–3884. https://doi.org/10.1016/0016-7037(91)90082-g

    Article  CAS  Google Scholar 

  21. Macpherson, C.G., Hilton, D.R., Newman, S., and Mattey, D.P., CO2, 13C/12C and H2O variability in natural basaltic glasses: A study comparing stepped heating and ftir spectroscopic techniques, Geochim. Cosmochim. Acta, 1999, vol. 63, nos. 11–12, pp. 1805–1813. https://doi.org/10.1016/s0016-7037(99)00124-6

    Article  CAS  Google Scholar 

  22. Bresson, B., Masse, S., Zanni, H., and Noik, C., Tricalcium silicate hydration at high temperature. A 29Si and 1H NMR investigation, Nuclear Magnetic Resonance Spectroscopy of Cement-Based Materials, Colombet, P., Zanni, H., Grimmer, A.R., and Sozzani, P., Eds., Berlin: Springer, 1998, pp. 209–215. https://doi.org/10.1007/978-3-642-80432-8_15

  23. Sevelsted, T.F. and Skibsted, J., Carbonation of C–S–H and C–A–S–H samples studied by 13C, 27Al and 29Si MAS NMR spectroscopy, Cem. Concr. Res., 2015, vol. 71, pp. 56–65. https://doi.org/10.1016/j.cemconres.2015.01.019

    Article  CAS  Google Scholar 

Download references

Funding

For the purpose of doing this research, writing, and/or publishing this paper, the authors didn’t receive any funding from external agencies.

Author information

Authors and Affiliations

  1. Department of Civil Engineering, University College of Engineering, Nagercoil, India

    Simon Judes Sujatha

  2. Department of Civil Engineering, PET Engineering College, Nagercoil, India

    Victor Rajasekaran Ruban Daniel

  3. Department of Civil Engineering, Noorul Islam Centre for Higher Education, Tamil Nadu, India

    Thanga Jebarsan

  4. Department of Civil Engineering, Vels University, Chennai, India

    Anandakumar Daisy Sheena

Authors
  1. Simon Judes Sujatha
    View author publications

    Search author on:PubMed Google Scholar

  2. Victor Rajasekaran Ruban Daniel
    View author publications

    Search author on:PubMed Google Scholar

  3. Thanga Jebarsan
    View author publications

    Search author on:PubMed Google Scholar

  4. Anandakumar Daisy Sheena
    View author publications

    Search author on:PubMed Google Scholar

Corresponding author

Correspondence to Victor Rajasekaran Ruban Daniel.

Ethics declarations

The authors of this work declare that they have no conflicts of interest.

Additional information

Publisher’s Note.

Allerton Press remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

AI tools may have been used in the translation or editing of this article.

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Simon Judes Sujatha, Daniel, V.R., Jebarsan, T. et al. Aluminosilicate Gel Formation in Alkali-Activated Fly Ash: An NMR Spectroscopic Study. Coke Chem. 68, 313–320 (2025). https://doi.org/10.3103/S1068364X25600198

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Version of record:

  • Issue date:

  • DOI: https://doi.org/10.3103/S1068364X25600198