Towards the Understanding of the pH Dependency of the Chloride Binding of Portland Cement Pastes

Abstract Hydrated Portland cement paste exposed to a NaCl solution was acidified by adding HCl in small steps, gradually lowering the pH. The chloride binding of the cement paste changed as a function of the pH. For the range of pH from 13.2 to 12.2, decreasing pH resulted in a considerable increase...

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Bibliographic Details
Published inNordic concrete research Vol. 58; no. 1; pp. 143 - 162
Main Authors Machner, Alisa, Hemstad, Petter, De Weerdt, Klaartje
Format Journal Article
LanguageEnglish
Published Sciendo 01.06.2018
Subjects
c-s-h
chloride binding
leaching
thermodynamic modelling
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Summary:Abstract Hydrated Portland cement paste exposed to a NaCl solution was acidified by adding HCl in small steps, gradually lowering the pH. The chloride binding of the cement paste changed as a function of the pH. For the range of pH from 13.2 to 12.2, decreasing pH resulted in a considerable increase in the chloride binding. At a pH of 11, the cement paste showed almost no chloride binding. In order to explain the changes in chloride binding upon lowering the pH, the phase assemblage was investigated with SEM-EDS, TGA and XRD and compared to a thermodynamic modelling.
ISSN:2545-2819
2545-2819
DOI:10.2478/ncr-2018-0009