Role of MgO/Cl2 and H2O/Cl2 Molar Ratios on Microstructure and Strength Degradation of Magnesium Oxychloride Cement When Exposed to Water
Source abstract
Abstract
This study investigated the role of MgO/Cl 2 ( M ) and H 2 O/Cl 2 ( H ) molar ratios on microstructure and strength degradation of magnesium oxychloride cement (MOC) when exposed to water. The M or H molar ratios were systematically varied ( M of 5, 9, or 13; H from 10 to 30) by adjusting the proportions of raw materials and water. Experimental characterization included isothermal calorimetry, X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, and compressive strength measurements before and after water exposure. The test results indicate that low M molar ratios promote a greater heat of hydration and the formation of Phases 3 and 5 as dominant hydration products, resulting in higher compressive strength and lower porosity, along with reduced strength degradation upon water exposure. Conversely, a high M molar ratio of 13 leads to brucite-dominant phase assemblages exceeding 91 wt.%, substantially reducing compressive strength. Furthermore, increasing H molar ratios contributes to additional brucite formation and a further reduction in compressive strength.
Source: openalex_inverted_index · Quality: baseline
Research context
OpenAlex topics: Magnesium Oxide Properties and Applications · Magnesium Alloys: Properties and Applications · Concrete and Cement Materials Research
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (53)
Show source-provided references
1. Ahmad, F., Rawat, S., Yang, R., Zhang, L., Fanna, D. J., Soe, K., & Zhang, Y. (2025a). Effect of metakaolin and ground granulated blast furnace slag on the performance of hybrid fibre-reinforced magnesium oxychloride cement-based composites. International Journal of Civil Engineering, 23(5), 853–868. https://doi.org/10.1007/s40999-025-01074-410.1007/s40999-025-01074-4 ↗
2. Ahmad, F., Rawat, S., Yang, R. C., Zhang, L., Guo, Y., Fanna, D. J., & Zhang, Y. (2024a). Effect of hybrid fibres on mechanical behaviour of magnesium oxychloride cement-based composites. Construction and Building Materials, 424, 135937. https://doi.org/10.1016/j.conbuildmat.2024.13593710.1016/j.conbuildmat.2024.135937 ↗
3. Ahmad, F., Rawat, S., Yang, R. C., Zhang, L., & Zhang, Y. (2025b). Fire resistance and thermal performance of hybrid fibre-reinforced magnesium oxychloride cement-based composites. Construction and Building Materials, 472, 140867. https://doi.org/10.1016/j.conbuildmat.2025.14086710.1016/j.conbuildmat.2025.140867 ↗
4. Ahmad, F., Rawat, S., & Zhang, Y. (2024b). Magnesium oxychloride cement: Development, opportunities and challenges. Applied Sciences, 14(7), 3074. https://doi.org/10.3390/app1407307410.3390/app14073074 ↗
5. Aiken, T. A., Kwasny, J., Russell, M., McPolin, D., & Bagnall, L. (2022a). Effect of partial MgO replacement on the properties of magnesium oxychloride cement. Cement and Concrete Composites, 134, 104791. https://doi.org/10.1016/j.cemconcomp.2022.10479110.1016/j.cemconcomp.2022.104791 ↗
6. Aiken, T. A., Russell, M., McPolin, D., Gavin, B., Nugent, L., & Bagnall, L. (2022b). Effect of molar ratios and curing conditions on the moisture resistance of magnesium oxychloride cement. Journal of Materials in Civil Engineering, 34(2), 04021426. https://doi.org/10.1061/(ASCE)MT.1943-5533.000407010.1061/(ASCE)MT.1943-5533.0004070 ↗
7. Altmaier, M., Metz, V., Neck, V., Müller, R., & Fanghänel, T. (2003). Solid-liquid equilibria of Mg (OH) 2 (cr) and Mg2 (OH) 3Cl· 4H2O (cr) in the system Mg-Na-H-OH-Cl-H2O at 25 C. Geochimica Et Cosmochimica Acta, 67(19), 3595–3601. https://doi.org/10.1016/S0016-7037(03)00165-010.1016/S0016-7037(03)00165-0 ↗
8. ASTM A. (2013). Standard test method for compressive strength of hydraulic cement mortars (using 2-in. or [50-mm] cube specimens). Annual Book of ASTM Standards, 4(1), 1–9. https://doi.org/10.1520/C0109_C0109M-2110.1520/C0109_C0109M-21 ↗
9. Ba, H., & Guan, H. (2009). Influence of MgO/MgCl2 molar ratio on phase stability of magnesium oxychloride cement. Journal of Wuhan University of Technology-Mater Sci Ed, 24(3), 476–481.10.1007/s11595-009-3476-3 ↗
10. Chan, J., & Li, Z. (2006). Influence of fly ash on the properties of magnesium oxychloride cement. Measuring, Monitoring and Modeling Concrete Properties: An International Symposium Dedicated to Professor Surendra P. Shah, Northwestern University, USA10.1007/978-1-4020-5104-3_41 ↗
11. Chau, C. K., & Li, Z. (2008). Accelerated reactivity assessment of light burnt magnesium oxide. Journal of the American Ceramic Society, 91(5), 1640–1645. https://doi.org/10.1111/j.1551-2916.2008.02330.x10.1111/j.1551-2916.2008.02330.x ↗
12. Cui, Y., Liu, Z., Huang, J., Zhang, W., Wang, Y., Zhu, J., & Deng, D. (2025). Effect of free CaO content on the phase composition of magnesium oxychloride cement. Cement and Concrete Composites, 157, 105906. https://doi.org/10.1016/j.cemconcomp.2024.10590610.1016/j.cemconcomp.2024.105906 ↗
13. Faltysová, I., Lauermannová, A.-M., Lojka, M., Pavlík, Z., Pavlíková, M., Keppert, M., & Jankovský, O. (2022). Study of formation of magnesium oxychloride phase MOC-518 by isothermal calorimetry. AIP Conference Proceedings10.1063/5.0093498 ↗
14. Feng, Y., Alves, Z., Peng, L., & Novais, R. M. (2025). The impact of industrial waste on hydration behavior, mechanical performance, and water resistance of magnesium oxychloride cement. Construction and Building Materials, 489, 142320. https://doi.org/10.1016/j.conbuildmat.2025.14232010.1016/j.conbuildmat.2025.142320 ↗
15. Gong, W., Wang, N., & Zhang, N. (2022). Effect of metakaolin on water resistance of magnesium oxychloride cement. ACI Materials Journal, 119(1), 47–57. https://doi.org/10.14359/5173425410.14359/51734254 ↗
16. Guan, B., He, Z., Wei, F., Wang, F., & Yu, J. (2022). Effects of fly ash and hexadecyltrimethoxysilane on the compressive properties and water resistance of magnesium oxychloride cement. Polymers, 15(1), 172. https://doi.org/10.3390/polym1501017210.3390/polym15010172 ↗
17. Guo, Y., Zhang, Y., Soe, K., & Pulham, M. (2018). Recent development in magnesium oxychloride cement. Structural Concrete, 19(5), 1290–1300. https://doi.org/10.1002/suco.20180007710.1002/suco.201800077 ↗
18. Guo, Y., Zhang, Y., Soe, K., Wuhrer, R., Hutchison, W. D., & Timmers, H. (2021). Development of magnesium oxychloride cement with enhanced water resistance by adding silica fume and hybrid fly ash-silica fume. Journal of Cleaner Production, 313, 127682. https://doi.org/10.1016/j.jclepro.2021.12768210.1016/j.jclepro.2021.127682 ↗
19. Hamada, H. M., Al-Attar, A., Askar, M. K., Beddu, S., & Majdi, A. (2025). Research progress on improving the water resistance of magnesium oxychloride cement (MOC). International Journal of Concrete Structures and Materials, 19(1), 76. https://doi.org/10.1186/s40069-025-00808-x10.1186/s40069-025-00808-x ↗
20. He, P., Poon, C. S., & Tsang, D. C. (2017). Effect of pulverized fuel ash and CO2 curing on the water resistance of magnesium oxychloride cement (MOC). Cement and Concrete Research, 97, 115–122. https://doi.org/10.1016/j.cemconres.2017.03.00510.1016/j.cemconres.2017.03.005 ↗
21. Huang, Q., Zheng, W., Xiao, X., Dong, J., Wen, J., & Chang, C. (2021). Effects of fly ash, phosphoric acid, and nano-silica on the properties of magnesium oxychloride cement. Ceramics International, 47(24), 34341–34351. https://doi.org/10.1016/j.ceramint.2021.08.34710.1016/j.ceramint.2021.08.347 ↗
22. Huang, T., Yuan, Q., & Deng, D. (2019). The role of phosphoric acid in improving the strength of magnesium oxychloride cement pastes with large molar ratios of H2O/MgCl2. Cement and Concrete Composites, 97, 379–386. https://doi.org/10.1016/j.cemconcomp.2019.01.01310.1016/j.cemconcomp.2019.01.013 ↗
23. Jiříčková, A., Lojka, M., Lauermannová, A.-M., Antončík, F., Sedmidubský, D., Pavlíková, M., Záleská, M., Pavlík, Z., & Jankovský, O. (2020). Synthesis, structure, and thermal stability of magnesium oxychloride 5Mg(OH)2∙ MgCl2∙ 8H2O. Applied Sciences, 10(5), 1683. https://doi.org/10.3390/app1005168310.3390/app10051683 ↗
24. Karimi, Y., & Monshi, A. (2011). Effect of magnesium chloride concentrations on the properties of magnesium oxychloride cement for nano SiC composite purposes. Ceramics International, 37(7), 2405–2410. https://doi.org/10.1016/j.ceramint.2011.05.08210.1016/j.ceramint.2011.05.082 ↗
25. Li, C., & Yu, H. (2010). Influence of fly ash and silica fume on water-resistant property of magnesium oxychloride cement. Journal of Wuhan University of Technology-Mater Sci Ed, 25(4), 721–724.10.1007/s11595-010-0079-y ↗
26. Li, K., Wang, Y., Yao, N., & Zhang, A. (2020). Recent progress of magnesium oxychloride cement: Manufacture, curing, structure and performance. Construction and Building Materials, 255, 119381. https://doi.org/10.1016/j.conbuildmat.2020.11938110.1016/j.conbuildmat.2020.119381 ↗
27. Li, K., Wang, Y., Zhang, X., Wang, X., & Zhang, A. (2021). Raw material ratio optimisation of magnesium oxychloride cement using response surface method. Construction and Building Materials, 272, 121648.10.1016/j.conbuildmat.2020.121648 ↗
28. Li, X., Zhou, Y., Zhang, X., Zheng, W., Chang, C., Ren, X., Zeng, J., Hai, C., & Shen, Y. (2018). Experimental investigation of thermal and mechanical properties of magnesium oxychloride cement with form-stable phase change material. Construction and Building Materials, 186, 670–677. https://doi.org/10.1016/j.conbuildmat.2018.07.11310.1016/j.conbuildmat.2018.07.113 ↗
29. Li, Y., Li, Z., Pei, H., & Yu, H. (2016). The influence of FeSO4 and KH2PO4 on the performance of magnesium oxychloride cement. Construction and Building Materials, 102, 233–238.10.1016/j.conbuildmat.2015.10.186 ↗
30. Li, Z., & Chau, C. (2007). Influence of molar ratios on properties of magnesium oxychloride cement. Cement and Concrete Research, 37(6), 866–870. https://doi.org/10.1016/j.cemconres.2007.03.01510.1016/j.cemconres.2007.03.015 ↗
31. Liu, Z., Balonis, M., Huang, J., Sha, A., & Sant, G. (2017). The influence of composition and temperature on hydrated phase assemblages in magnesium oxychloride cements. Journal of the American Ceramic Society, 100(7), 3246–3261. https://doi.org/10.1111/jace.1481710.1111/jace.14817 ↗
32. Ma, C., Chen, G., Cao, L., Zhou, H., & Ren, W. (2022). Effects and mechanisms of waste gypsum influencing the mechanical properties and durability of magnesium oxychloride cement. Journal of Cleaner Production, 339, 130679. https://doi.org/10.1016/j.jclepro.2022.13067910.1016/j.jclepro.2022.130679 ↗
33. Ma, C., Feng, S., Zhang, Z., Chen, G., Shi, J., Song, D., Zhou, H., Dong, B., & Du, Y. (2023). Effects of various gypsum on early-age hydration behavior of magnesium oxychloride cement (MOC) C. Ma et al. Journal of Thermal Analysis and Calorimetry, 148(9), 3283–3294.10.1007/s10973-023-11983-y ↗
34. Pu, L., Wang, J., Pang, K. S. H., & Ruan, S. (2024). Enhancing water resistance in magnesium oxychloride cement modified with sodium dihydrogen phosphate at low MgO concentrations. Construction and Building Materials, 440, 137407.10.1016/j.conbuildmat.2024.137407 ↗
35. Rodríguez-Alfaro, L. F., Torres-Martínez, L. M., Treviño-Garza, M. Z., Vázquez-Guillén, J. M., Rodríguez-Padilla, C., & Luévano-Hipólito, E. (2024). Design and fabrication of photocatalytic magnesium oxychloride cement with improved moisture stability: A step towards sustainable construction. Construction and Building Materials, 414, 134804. https://doi.org/10.1016/j.conbuildmat.2023.13480410.1016/j.conbuildmat.2023.134804 ↗
36. Scrivener, K., Snellings, R., Lothenbach, B., C Press. (2016). A practical guide to microstructural analysis of cementitious materials (Vol. 540). CRC Press.
37. Sglavo, V. M., De Genua, F., Conci, A., Ceccato, R., & Cavallini, R. (2011). Influence of curing temperature on the evolution of magnesium oxychloride cement. Journal of Materials Science, 46(20), 6726–6733. https://doi.org/10.1007/s10853-011-5628-z10.1007/s10853-011-5628-z ↗
38. Singh, A., Kumar, R., & Goel, P. (2021). Factors influencing strength of magnesium oxychloride cement. Construction and Building Materials, 303, 124571. https://doi.org/10.1016/j.conbuildmat.2021.12457110.1016/j.conbuildmat.2021.124571 ↗
39. Snellings, R., Chwast, J., Cizer, Ö., De Belie, N., Dhandapani, Y., Durdzinski, P., Elsen, J., Haufe, J., Hooton, D., & Patapy, C. (2018). Report of TC 238-SCM: Hydration stoppage methods for phase assemblage studies of blended cements—Results of a round robin test. Materials and Structures, 51(4), 111. https://doi.org/10.1617/s11527-018-1237-510.1617/s11527-018-1237-5 ↗
40. Sun, J., Song, Z., Zhang, Y., Zhang, Y., Zhao, S., Guo, M.-Z., & Jiang, L. (2024). Effect of red mud and phosphate on water resistance and hydration mechanism of magnesium oxychloride cement. Construction and Building Materials, 413, 134844. https://doi.org/10.1016/j.conbuildmat.2023.13484410.1016/j.conbuildmat.2023.134844 ↗
41. Tan, Y., Liu, Y., & Grover, L. (2014). Effect of phosphoric acid on the properties of magnesium oxychloride cement as a biomaterial. Cement and Concrete Research, 56, 69–74. https://doi.org/10.1016/j.cemconres.2013.11.00110.1016/j.cemconres.2013.11.001 ↗
42. Urwongse, L., & Sorrell, C. A. (1980). The system MgO-MgCl2-H2O at 23° C. Journal of the American Ceramic Society, 63(9–10), 501–504.10.1111/j.1151-2916.1980.tb10752.x ↗
43. Venkatesh, V., & Shanmugasundaram, M. (2024). Enhancement of mechanical and microstructural characteristics of magnesium oxychloride cement with metasteatite. Case Studies in Construction Materials, 21, e03683. https://doi.org/10.1016/j.cscm.2024.e0368310.1016/j.cscm.2024.e03683 ↗
44. Wang, D., Di, S., Gao, X., Wang, R., & Chen, Z. (2020). Strength properties and associated mechanisms of magnesium oxychloride cement-solidified urban river sludge. Construction and Building Materials, 250, 118933. https://doi.org/10.1016/j.conbuildmat.2020.11893310.1016/j.conbuildmat.2020.118933 ↗
45. Wang, Y., Wang, H., Zhang, L., Peng, L., Lyu, S., & Huang, L. (2024). Optimization of raw-material ratios and curing temperature of magnesium oxychloride cement. Construction and Building Materials, 435, 136795. https://doi.org/10.1016/j.conbuildmat.2024.13679510.1016/j.conbuildmat.2024.136795 ↗
46. Wen, J., Yu, H., Xiao, X. Y., & Dong, J. M. (2015). Influence of materials ratio on the hydration process of magnesium oxychloride cement. Materials Science Forum, 817, 180–184. https://doi.org/10.4028/www.scientific.net/MSF.817.18010.4028/www.scientific.net/MSF.817.180 ↗
47. Xie, Y., Wang, H., Guo, Y., Wang, C., Cui, H., & Xue, J. (2024). Mechanical performance and water resistance of biochar admixture lightweight magnesium oxychloride cement. Science of the Total Environment, 912, 168773. https://doi.org/10.1016/j.scitotenv.2023.16877310.1016/j.scitotenv.2023.168773 ↗
48. Xu, B., Ma, H., Hu, C., Yang, S., & Li, Z. (2016). Influence of curing regimes on mechanical properties of magnesium oxychloride cement-based composites. Construction and Building Materials, 102, 613–619. https://doi.org/10.1016/j.conbuildmat.2015.10.20510.1016/j.conbuildmat.2015.10.205 ↗
49. Ye, Q., Wang, W., Zhang, W., Li, J., & Chen, H. (2018). Tuning the phase structure and mechanical performance of magnesium oxychloride cements by curing temperature and H2O/MgCl2 ratio. Construction and Building Materials, 179, 413–419. https://doi.org/10.1016/j.conbuildmat.2018.05.25710.1016/j.conbuildmat.2018.05.257 ↗
50. Yuan, Q., Zhang, K., Huang, T., Liu, X., & Wang, Y. (2024). Rheological behaviors evolution and setting mechanism of magnesium oxychloride cement paste. Construction and Building Materials, 440, 137506. https://doi.org/10.1016/j.conbuildmat.2024.13750610.1016/j.conbuildmat.2024.137506 ↗
51. Zhao, S., Song, Z., Zhang, Y., Zhang, Y., Sun, J., Guo, M.-Z., Jiang, L., & Jin, W. (2024). Utilization of phosphogypsum and phosphate in improving water resistance of magnesium oxychloride cement. Construction and Building Materials, 444, 137777. https://doi.org/10.1016/j.conbuildmat.2024.13777710.1016/j.conbuildmat.2024.137777 ↗
52. Zhong, J., Liu, P., Mo, L., Lu, D., & Peng, S. (2023). Recycling MgO from the waste magnesium oxychloride cement (MOC): Properties, CO2 footprint and reuse in MOC. Journal of Cleaner Production, 415, 137782. https://doi.org/10.1016/j.jclepro.2023.13778210.1016/j.jclepro.2023.137782 ↗
53. Zhou, Z., Chen, H., Li, Z., & Li, H. (2015). Simulation of the properties of MgO-MgfCl2-H2O system by thermodynamic method. Cement and Concrete Research, 68, 105–111. https://doi.org/10.1016/j.cemconres.2014.11.00610.1016/j.cemconres.2014.11.006 ↗