Abstract
This study presents for the first time a systematic investigation of the thermodynamic properties of sodium aluminosilicate hydrate (N-A-S-H), through dissolution of pure synthetic N-A-S-H gels. Changes to the chemical composition and gel structure of N-A-S-H were determinedviacharacterisation of the solid phase before and after dissolution by multinuclear solid state nuclear magnetic resonance spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, and X-ray diffraction measurements. The correlations between the bulk Si/Al ratio of the N-A-S-H phase and its thermodynamic properties were studied by characterisation of the aqueous phase and calculation of solubility constants. The solubility of synthetic N-A-S-H was compared with the solubility of metakaolin-based geopolymers with similar bulk Si/Al ratios. The solubility (log10 Ksp) of both the synthetic N-A-S-H gels and metakaolin-based geopolymers showed a close to linear correlation with the bulk Si/Al ratio of the phase. Lower solubility was observed for N-A-S-H gels and geopolymers with a higher bulk Si/Al ratio. This new insight is fundamental to understanding the physiochemical properties of geopolymers, and provides essential information for predicting their long-term stability and durability.
Original language | English |
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Pages (from-to) | 13968-13984 |
Number of pages | 17 |
Journal | Dalton Transactions |
Volume | 50 |
Issue number | 39 |
Early online date | 7 Sept 2021 |
DOIs | |
Publication status | Published - 21 Oct 2021 |
ASJC Scopus subject areas
- Inorganic Chemistry
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Avance III 500 MHz Nuclear Magnetic Resonance (NMR) Spectrometer (9West)
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