Impact of chloride on the mineralogy of hydrated Portland cement systems

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2010.03.002· OSTI ID:21443307

Balonis, Magdalena ^[1]; Lothenbach, Barbara ^[2]; Le Saout, Gwenn ^[2]; Glasser, Fredrik P ^[1]

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1. Department of Chemistry, Meston Building, University of Aberdeen, Aberdeen, AB24 3UE Scotland (United Kingdom)
2. EMPA, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Concrete and Construction Chemistry, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

Chloride ion is in part bound into ordinary Portland cement paste and modifies its mineralogy. To understand this a literature review of its impacts has been made and new experimental data were obtained. Phase pure preparations of Friedel's salt, Ca{sub 4}Al{sub 2}(Cl){sub 1.95}(OH){sub 12.05}.4H{sub 2}O, and Kuzel's salt, Ca{sub 4}Al{sub 2}(Cl)(SO{sub 4}){sub 0.5}(OH){sub 12}.6H{sub 2}O, were synthesized and their solubilities were measured at 5, 25, 55 and 85 {sup o}C. After equilibration, solid phases were analysed by X-ray diffraction while the aqueous solutions were analysed by atomic absorption spectroscopy and ion chromatography. The solid solutions and interactions of Friedel's salt with other AFm phases were determined at 25 {sup o}C experimentally and by calculations. In hydrated cements, anion sites in AFm are potentially occupied by OH, SO{sub 4} and CO{sub 3} ions whereas Cl may be introduced under service conditions. Chloride readily displaces hydroxide, sulfate and carbonate in the AFm structures. A comprehensive picture of phase relations of AFm phases and their binding capacity for chloride is provided for pH {approx} 12 and 25 {sup o}C. The role of chloride in AFt formation and its relevance to corrosion of embedded steel are discussed in terms of calculated aqueous [Cl{sup -}]/[OH{sup -}] molar ratios.

• OSTI ID: 21443307
• Journal Information: Cement and Concrete Research, Vol. 40, Issue 7; Other Information: DOI: 10.1016/j.cemconres.2010.03.002; PII: S0008-8846(10)00058-X; 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 COMPOUNDS
ANIONS
AQUEOUS SOLUTIONS
ATOMIC FORCE MICROSCOPY
CALCIUM COMPOUNDS
CARBONATES
CHLORIDES
CHLORINE IONS
CORROSION
HYDROXIDES
INTERACTIONS
ION EXCHANGE CHROMATOGRAPHY
PH VALUE
PORTLAND CEMENT
SOLID SOLUTIONS
SOLUBILITY
STEELS
SULFATES
TEMPERATURE RANGE 0273-0400 K
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BUILDING MATERIALS
CARBON ADDITIONS
CARBON COMPOUNDS
CEMENTS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
CHROMATOGRAPHY
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
HALIDES
HALOGEN COMPOUNDS
HOMOGENEOUS MIXTURES
HYDROGEN COMPOUNDS
IONS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MICROSCOPY
MIXTURES
OXYGEN COMPOUNDS
SCATTERING
SEPARATION PROCESSES
SOLUTIONS
SPECTROSCOPY
SULFUR COMPOUNDS
TEMPERATURE RANGE
TRANSITION ELEMENT ALLOYS