MgO-based cements – Current status and opportunities

Authors

  • Ellina Bernard Empa, Swiss Federal Laboratories for Materials Science and Technology
  • Hoang Nguyen Fibre and Particle Engineering Research Unit, University of Oulu, Oulu, Finland
  • Shiho Kawashima Columbia University, Department of Civil Engineering and Engineering Mechanics, 500 West 120th street, New York, NY 10027, USA
  • Barbara Lothenbach Empa, Swiss Federal Laboratories for Materials Science and Technology
  • Hegoi Manzano
  • John Provis
  • Allan Scott
  • Cise Unluer
  • Frank Winnefeld
  • Paivo Kinnunen Fibre and Particle Engineering Research Unit, University of Oulu, Oulu, Finland

DOI:

https://doi.org/10.21809/rilemtechlett.2023.177

Keywords:

Magnesia-based cements, MgO supply, Low pH cements, Low-to-negative CO2 emissions, Magnesia oxysulfate cement, Magnesia oxychloride cement, Magnesia carbonate cement, Magnesia silicate cement

Abstract

The cement industry is a major contributor to the anthropogenic CO2 emissions, with about 8% of all emissions coming from this sector. The global cement and concrete association has set a goal to achieve net-zero CO2 concrete by 2050, with 45% of the reduction coming from alternatives to Portland cement, substitution, and carbon capture and utilization/storage (CCU/S) approaches. Magnesia-based cements offer a conceivable solution to this problem due to their potential for low-to-negative CO2 emissions (CCU/S) but also being alternatives to Portland cement. The sources of magnesia can come from magnesium silicates or desalination brines which are carbon free for raw-material-related emissions (cf. carbonated rocks). This opens up possibilities for low or even net-negative carbon emissions. However, research on magnesia-based cements is still in its early stages.

In this paper, we summarize the current understanding of different MgO-based cements and their chemistries: magnesia oxysulfate cement, magnesia oxychloride cement, magnesia carbonate cement, and magnesia silicate cement. We also discuss relevant research needed for MgO-based cements and concretes including the issues relating to the low pH of these cements and suitability of steel reinforcement. Alternatives reinforcements, suitable admixtures, and durability studies are the most needed for the further development of MgO-based concretes to achieve a radical CO2 reduction in this industry. Additionally, techno-economic and life cycle assessments are also needed to assess the competition of raw materials and the produced binder or concrete with other solutions. Overall, magnesia-based cements are a promising emerging technology that requires further research and development to realize their potential in reducing CO2 emissions in the construction industry.

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Published

16.11.2023

How to Cite

(1)
Bernard, E.; Nguyen, H.; Kawashima, S.; Lothenbach, B.; Manzano, H. .; Provis, J.; Scott, A.; Unluer, C.; Winnefeld, F.; Kinnunen, P. MgO-Based Cements – Current Status and Opportunities. RILEM Tech Lett 2023, 8, 65-78.

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