Structural evolution of calcium sodium aluminosilicate hydrate (C-(N-)A-S-H) gels induced by water exposure: The impact of Na leaching

Chen Liu, Zhenming Li, Shuai Nie*, Jørgen Skibsted, Guang Ye

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)
20 Downloads (Pure)

Abstract

Calcium sodium aluminosilicate hydrate C-(N-)A-S-H gels, formed through the alkali-activation of calcium silicate-based materials, may exhibit greater susceptibility to aqueous environments when compared to traditional C-(A-)S-H phases formed by hydration of blended Portland cements. This study investigates structural changes in synthesized C-(N-)A-S-H gels triggered by water immersion. Three gels have been examined, each with stoichiometrically controlled ratios of Ca/Si (0.8 and 1.2), Al/Si (0.1 and 0.3), and Na/Si (0.1, 0.2, and 0.3). The gel with a higher Ca/Si ratio demonstrated enhanced resistance to water leaching and only experienced marginal decalcification whereas the gels with lower Ca/Si ratios exhibited more pronounced effects including leaching losses of Si. Notably, all gels displayed rapid and substantial sodium leaching, contributing to an increased degree of polymerization for the aluminosilicate tetrahedra in the gels. A plausible mechanism for this change is that Na leaches out from the interlayer and Ca ions progressively take over the role of charge compensators in the interlayer of the C-(N-)A-S-H structure.

Original languageEnglish
Article number107432
Number of pages13
JournalCement and Concrete Research
Volume178
DOIs
Publication statusPublished - 2024

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Keywords

  • Na, Al and Si NMR
  • C-(N-)A-S-H gel
  • Leaching
  • Structural evolution
  • Water immersion

Fingerprint

Dive into the research topics of 'Structural evolution of calcium sodium aluminosilicate hydrate (C-(N-)A-S-H) gels induced by water exposure: The impact of Na leaching'. Together they form a unique fingerprint.

Cite this