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Responsible for around 8 % of global CO2 emissions, the cement industry needs to drastically reduce its carbon footprint. One solution is to substitute the clinker of Ordinary Portland Cement (OPC) with oxides of lower calcium content such as blast furnace slag. These oxides inevitably have a lower reactivity than clinker but, if they contain enough calcium, their reactivity can be activated by an external source of alkalinity.
NMR, XRD, mechanical strength measurements, bound water quantification and isothermal calorimetry were combined to contrast the degree of reaction and the paths followed by slag under the influence of three activators : sodium hydroxide, sodium carbonate and sodium silicate.
This work, conducted in collaboration with Saint Gobain Construction Chemicals, opens ways for the formulation of new cements with low carbon impact.
If you want to know more
C. Paillard, N. Sanson, J.-B. d’Espinose De Lacaillerie, M. Palacios, P. Boustingorry, M. Jachiet, C. Giraudeau, V. Kocaba, An experimental review of the reaction paths followed by alkali-activated slag pastes, Cement and Concrete Research 189 (2025) 107765.
https://doi.org/10.1016/j.cemconres.2024.107765.