Fe-containing phases in hydrated cements
- Paul Scherrer Institute, Laboratory for Waste Management, 5232 Villigen PSI (Switzerland)
- Empa, Laboratory for Concrete and Construction Chemistry, Überlandstrasse 129, 8600 Dübendorf (Switzerland)
- Ecole Polytechnique Federal de Lausanne (EPFL), Laboratory for Construction Materials, 1015 Lausanne (Switzerland)
In this study synchrotron X-ray absorption spectroscopy (XAS) has been applied, an element specific technique which allows Fe-containing phases to be identified in the complex mineral mixture of hydrated cements. Several Fe species contributed to the overall Fe K-edge spectra recorded on the cement samples. In the early stage of cement hydration ferrite was the dominant Fe-containing mineral. Ferrihydrite was detected during the first hours of the hydration process. After 1 day the formation of Al- and Fe-siliceous hydrogarnet was observed, while the amount of ferrihydrite decreased. The latter finding agrees with thermodynamic modeling, which predicts the formation of Fe-siliceous hydrogarnet in Portland cement systems. The presence of Al- and Fe-containing siliceous hydrogarnet was further substantiated in the residue of hydrated cement by performing a selective dissolution procedure. - Highlights: • Fe bound to ferrihydrite at early age hydration • Fe found to be stable in siliceous hydrogarnet at longer term age hydration • Fe-containing AFt and AFm phases are less stable than siliceous hydrogarnet. • The study demonstrates EXAFS used to identify amorphous or poorly crystalline phases.
- OSTI ID:
- 22323132
- Journal Information:
- Cement and Concrete Research, Vol. 58; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
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