Non-ideal solid solution aqueous solution modeling of synthetic calcium silicate hydrate

Colin S. Walker, David Savage, Mark Tyrer, K. Vala Ragnarsdottir

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43 Citations (Scopus)

Abstract

New data relevant to calcium silicate hydrate (C-S-H) gels prepared at room temperature have been obtained over a time period of up to 112 weeks. X-ray diffraction (XRD) indicates equilibrium was attained after 64 weeks. Coupled with fourier transform infrared (FT-IR) spectroscopy, a phase change in C-S-H gel at Ca/Si ≈ 1.0 was identified and the occurrence of portlandite as a distinct phase for Ca/Si > 1.64. The incongruent dissolution of C-S-H gel was modeled as a non-ideal solid solution aqueous solution (SSAS) between the end-member components CaH2SiO4 (CSH) and Ca(OH)2 (CH) using equations defining the solidus and solutus curves on a Lippmann phase diagram. Despite being semi-empirical, the model provides a reasonable and consistent fit to the solubility data and can therefore be used to describe the incongruent dissolution of C-S-H gels with compositions Ca/Si ≥ 1.0.

Original languageEnglish
Pages (from-to)502-511
Number of pages10
JournalCement and Concrete Research
Volume37
Issue number4
Early online date26 Jan 2007
DOIs
Publication statusPublished - Apr 2007
Externally publishedYes

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Keywords

  • pH
  • calcium silicate hydrate (C-S-H)
  • Ca(OH)
  • Modeling

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Ceramics and Composites

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