Iron in carbonate containing AFm phases

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2010.11.017· OSTI ID:21490054

Lothenbach, B; Le Saout, G ^[1]; Renaudin, G; Mesbah, A ^[2]; Filinchuk, Y ^[3]; Wichser, A ^[1]; Wieland, E ^[4]

---

1. Empa, Laboratory for Concrete and Construction Chemistry, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)
2. Clermont Universite, ENSCCF, Laboratoire des Materiaux Inorganiques, BP 10448, F-63000 Clermont-Ferrand (France)
3. Swiss-Norwegian Beam Lines at ESRF, 6 rue Jules Horowitz, BP 220, 38043 Grenoble (France)
4. Paul Scherrer Institute, Nuclear Energy and Safety Research Department, Laboratory for Waste Management, 5232 Villigen PSI (Switzerland)

One of the AFm phases in hydrated Portland cement is Ca{sub 3}(Al{sub x}Fe{sub 2} {sub -} {sub x})O{sub 6}.CaCO{sub 3}.nH{sub 2}O. It is based on hexagonal and platey structural elements and the interlayer structure incorporates CO{sub 3}{sup 2-}. The solid phases were experimentally synthesized and characterized by different techniques including X-ray techniques (XRD and EXAFS) and vibrational spectroscopy techniques (IR, Raman). Fe-monocarbonate (Fe-Mc) and Al-monocarbonate (Al-Mc) were found to be stable up to 50 {sup o}C, while Fe-hemicarbonate (Fe-Hc) was unstable with respect to Fe-Mc in the presence of calcite. Fe-Mc has a rhombohedral R3-barc symmetry which is different from the triclinic of the Al analogue. Both XRD and thermodynamic modelling of the liquid compositions indicated that Al-Mc and the Fe-Mc phases do not form solid solution. The solubility products were calculated experimentally at 20 {sup o}C and 50 {sup o}C. Under standards condition the solubility products and other thermodynamic parameters were estimated using temperature-solubility product extrapolation and found to be logK{sub S0} (Fe-Mc) = -34.59 {+-} 0.50, logK{sub S0} (Fe-Hc) = -30.83 {+-} 0.50 and logK{sub S0}(Al-Mc) = -31.32 {+-} 0.50.

• OSTI ID: 21490054
• Journal Information: Cement and Concrete Research, Vol. 41, Issue 3; Other Information: DOI: 10.1016/j.cemconres.2010.11.017; PII: S0008-8846(10)00260-7; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0008-8846
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
ALUMINIUM OXIDES
ATOMIC FORCE MICROSCOPY
CALCITE
CALCIUM CARBONATES
EXTRAPOLATION
FINE STRUCTURE
IRON
IRON OXIDES
LIQUIDS
PORTLAND CEMENT
SIMULATION
SOLID SOLUTIONS
SOLIDS
SOLUBILITY
TEMPERATURE RANGE 0273-0400 K
TRIGONAL LATTICES
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
BUILDING MATERIALS
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CEMENTS
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
DISPERSIONS
ELEMENTS
FLUIDS
HOMOGENEOUS MIXTURES
IRON COMPOUNDS
MATERIALS
MATHEMATICAL SOLUTIONS
METALS
MICROSCOPY
MINERALS
MIXTURES
NUMERICAL SOLUTION
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SOLUTIONS
SPECTROSCOPY
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS