Thermodynamic modelling of the effect of temperature on the hydration and porosity of Portland cement

Journal Article · Tue Jan 15 04:00:00 EST 2008 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2007.08.017· OSTI ID:21033062

Lothenbach, Barbara ^[1]; Matschei, Thomas ^[1]; Moeschner, Goeril ^[1]; Glasser, Fred P ^[2]

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1. Empa, Laboratory for Concrete and Construction Chemistry, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)
2. University of Aberdeen, Department of Chemistry, Meston Walk, Old Aberdeen, AB24 3UE, Scotland (United Kingdom)

The composition of the phase assemblage and the pore solution of Portland cements hydrated between 0 and 60 deg. C were modelled as a function of time and temperature. The results of thermodynamic modelling showed a good agreement with the experimental data gained at 5, 20, and 50 deg. C. At 5 and at 20 deg. C, a similar phase assemblage was calculated to be present, while at approximately 50 deg. C, thermodynamic calculations predicted the conversion of ettringite and monocarbonate to monosulphate. Modelling showed that in Portland cements which have an Al{sub 2}O{sub 3}/SO{sub 3} ratio of > 1.3 (bulk weight), above 50 deg. C monosulphate and monocarbonate are present. In Portland cements which contain less Al (Al{sub 2}O{sub 3}/SO{sub 3} < 1.3), above 50 deg. C monosulphate and small amounts of ettringite are expected to persist. A good correlation between calculated porosity and measured compressive strength was observed.

• OSTI ID: 21033062
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 1 Vol. 38; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPRESSION STRENGTH
HYDRATION
POROSITY
PORTLAND CEMENT
SIMULATION
SULFITES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TIME DEPENDENCE