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Calorimetric and thermogravimetric study on the influence of calcium sulfate on the hydration of ye'elimite

Winnefeld, Frank ; Barlag, Stefan

In: Journal of Thermal Analysis and Calorimetry, 2010, vol. 101, no. 3, p. 949-957

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    Titre
    • Calorimetric and thermogravimetric study on the influence of calcium sulfate on the hydration of ye'elimite
    Auteur
    • Winnefeld, Frank. Empa, Swiss Federal Laboratories for Materials Testing and Research, Überlandstrasse 129, 8600, Dübendorf, Switzerland
    • Barlag, Stefan. Empa, Swiss Federal Laboratories for Materials Testing and Research, Überlandstrasse 129, 8600, Dübendorf, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Journal of Thermal Analysis and Calorimetry, 2010, vol. 101, no. 3, p. 949-957. Springer Netherlands
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:316127
    Summary
    Calcium sulfoaluminate (CSA) cements, which represent a CO2-friendly alternative to conventional Portland cements, are produced by blending CSA clinker with gypsum and/or anhydrite. The hydration kinetics and the hydrated phase assemblages of the main hydraulic phase ye'elimite (calcium sulfoaluminate) with calcium sulfate were studied by isothermal conduction calorimetry, thermogravimetric analysis, X-ray diffraction analysis and thermodynamic modelling. Two calcium sulfates with different reactivities (gypsum and anhydrite) were applied. It was found that the pure phase without any calcium sulfate addition exhibits very slow hydration kinetics during the first 10h. The hydration can be accelerated by the addition of calcium sulfate or (less effective) by increasing the pH of the aqueous phase. The amount of the calcium sulfate determines the ratio between the hydration products ettringite, monosulfate and amorphous aluminium hydroxide. The reactivity of the added calcium sulfate determines the early hydration kinetics. It was found that the more reactive gypsum was better suited to control the hydration behaviour of ye'elimite