Interpretation of the early stiffening process in alkali-activated slag pastes

Yubo Sun, Luiz Miranda de Lima, Laura Rossi, Dengwu Jiao, Zhenming Li, Guang Ye, Geert De Schutter*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
12 Downloads (Pure)

Abstract

To better understand early stiffening of AAS pastes, distinctive microstructural features by varying the silicate modulus (Ms) have been visualized with in-situ microscopy. In addition, the activation reaction was monitored with multiple approaches, while solid and liquid phases in hydrating AAS were characterized separately. In silicate-activated AAS, it was found fine granules of reaction products are intensively dispersed in the activator solution, leading to a less flocculated system. Compared to hydroxide-activated AAS, the development of interparticle connections was limited at early ages, whereas reaction products were detected with much smaller grain size, less crystalline phase, and higher Al incorporation. Results indicate that the stiffening of hydroxide-activated AAS is attributed to the formation of a well-percolated network through solid reaction products. Instead, massive fine granules of reaction products dispersed in the pore solution continuously develop, which may intensify the interparticle interactions and macroscopically results in the stiffening of a silicate-activated AAS.

Original languageEnglish
Article number107118
JournalCement and Concrete Research
Volume167
DOIs
Publication statusPublished - 2023

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

  • Alkali-activated slag
  • Early stiffening
  • Microstructure
  • Reaction products
  • Rheology

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