Title:
Hydration Mechanism of MgO-Nesquehonite Blends
Author(s):
Paula Montserrat-Torres, Barbara Lothenbach and Frank Winnefeld
Publication:
Symposium Paper
Volume:
362
Issue:
Appears on pages(s):
283-291
Keywords:
alternative binder, brucite, cement, eco-friendly, hydrated magnesium carbonate, magnesia, nesquehonite
DOI:
10.14359/51740889
Date:
6/6/2024
Abstract:
High CO2 emissions are associated with the production of Portland cement. To reduce these emissions, alternative binders based on magnesium have been proposed. Magnesium carbonate hydrate cement prepared from MgO and carbonates such as e.g. hydromagnesite (Mg5(CO3)4(OH)2·4H2O) or nesquehonite (MgCO3ˑ3H2O) have the potential to bind carbonates during the hardening process. Such mixes develop adequate compressive strength, in contrast to pure MgO cement. This study investigates the hydration of MgO in the presence of nesquehonite as a carbonate source, a less stable and more reactive magnesium carbonate than hydromagnesite.
MgO pastes with different percentages of nesquehonite were prepared and analyzed with XRD, TGA, and FTIR to characterize the phases formed during hydration. Calorimetry was also used to follow the hydration kinetics up to 7 d. The results revealed that the addition of nesquehonite in MgO-based cements significantly delays the hydration. TGA and XRD analyses confirmed the formation of hydrous carbonate-containing brucite (HCB) in the presence of nesquehonite, characterized by its content of gel water and CO2. FTIR data further supported the presence of carbonate groups in HCB. At least 15 wt% of nesquehonite reacts to form HCB, contributing to the mechanical properties of MgO-based cements.
Related References:
1. Provis, J., 2014, "Green concrete or red herring? – Future of alkali-activated materials", Advances in Applied Ceramics, 113, 472-477.
2. Dong, H., Yang, E.-H., Unluer, C., Jin, F., and Al-Tabbaa, A., 2018, "Investigation of the properties of MgO recovered from reject brine obtained from desalination plants", Journal of Cleaner Production, 196, 100-108.
3. Morrison, J., Jauffret, G., Galvez-Martos, J.L., and Glasser, F.P., 2016, "Magnesium-based cements for CO2 capture and utilisation", Cement and Concrete Research, 85, 183-191.
4. Walling, S.A. and Provis, J.L., 2016, "Magnesia-based cements: a journey of 150 years, and cements for the future?", Chemical Reviews, 116(7), 4170-4204.
5. Vlasopoulos, N. and Cheeseman, C.R., Binder composition, Patent number US8496751B2, PCT/GB2009/001610, 30/06/2013, United States Patent.
6. German, A., Winnefeld, F., Lura, P., Rentsch, D., and Lothenbach, B., 2023, "Hydrous carbonatecontaining brucite (HCB) in MgO/hydromagnesite blends", Cement and Concrete Research, 173, 107304.
7. Jansen, D., German, A., Ectors, D., and Winnefeld, F., 2024, "Stacking faults of the hydrous carbonatecontaining brucite (HCB) phase in hydrated magnesium carbonate cements", Cement and Concrete Research, 175, 107371.
8. Winnefeld, F., Epifania, E., Montagnaro, F., and Gartner, E.M., 2019, "Further studies of the hydration of MgO-hydromagnesite blends", Cement and Concrete Research, 126, 105912.
9. Kuenzel, C., Zhang, F., Ferrándiz-Mas, V., Cheeseman, C.R., and Gartner, E.M., 2018, "The mechanism of hydration of MgO-hydromagnesite blends", Cement and Concrete Research, 103, 123-129.
10. Shi, R., Hao, Y., Chen, D., and Liu, W., 2023, "Effect of low nesquehonite addition on the hydration product and pore structure of reactive magnesia paste", Materials, 16(6), 2445.
11. Thomas, J.J., Musso, S., and Prestini, I., 2014, "Kinetics and activation energy of magnesium oxide hydration", Journal of the American Ceramic Society, 97(1), 275-282.
12. Snellings, R., Chwast, J., Cizer, Ö., De Belie, N., Dhandapani, Y., Durdziński, P., Elsen, J., Haufe, J., Hooton, D., Patapy, C., Santhanam, M., Scrivener, K., Snoeck, D., Steger, L., Tongbo, S., Vollpracht, A., Winnefeld, F., and Lothenbach, B., 2018, "RILEM TC-238 SCM recommendation on hydration stoppage by solvent exchange for the study of hydrate assemblages", Materials and Structures, 51.
13. Frost, R.L. and Kloprogge, J.T., 1999, "Infrared emission spectroscopic study of brucite", Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 55, 2195-2205.
14. Bahfenne, C., Bayyareddy, J., Frost, R., and Graham, J., 2008, "The structure of selected magnesium carbonate minerals - A near infrared and mid-infrared spectroscopic study", Polyhedron, 27.
15. White, W.B., 1971, "Infrared characterization of water and hydroxyl ion in the basic magnesium carbonate minerals", American Mineralogist: Journal of Earth and Planetary Materials, 56(1-2), 46-53.
16. Zhang, Z., Zheng, Y., Ni, Y., Liu, Z., Chen, J., and Liang, X., 2006, "Temperature- and pH-dependent morphology and FT−IR analysis of magnesium carbonate hydrates", The Journal of Physical Chemistry B, 110(26), 12969-12973.
17. Lu, S., Yan, P., Gao, Y., and Zhang, C., 2020, "Theoretical Investigation of the Energies, Structures, and Growth Properties of Hydromagnesite Surfaces", Crystal Growth & Design, 20(6), 3722-3731.
18. Lu, S., Yan, P., Gao, Y., Zhang, C., and Lu, J., 2020, "Insights into the structures, energies and electronic properties of nesquehonite surfaces by first-principles calculations", Advanced Powder Technology, 31(8), 3465-3473