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KALINA, L. BÍLEK, V. BARTONÍČKOVÁ, E. KALINA, M. HAJZLER, J. NOVOTNÝ, R.
Original Title
Doubts over capillary pressure theory in context with drying and autogenous shrinkage of alkali-activated materials
Type
journal article in Web of Science
Language
English
Original Abstract
One of the most important technological problems associated with alkali-activated materials is high shrinkage. In this study, shrinkage reducing admixtures (SRAs) based on amino alcohols were used in alkali-activated slag (AAS) as strong surfactants that should, in terms of capillary pressure theory, decrease shrinkage via the decrease in surface tension. Although the surface tension of the pore solution was reduced by SRAs, autogenous shrinkage was not affected in the long run, while drying shrinkage was noticeably reduced and simultaneous weight changes were dramatically increased. The expected retardation effect of SRAs on hydration was confirmed using isothermal calorimetry, strength development, mercury intrusion porosimetry and scanning electron microscopy. The obtained results suggest that the observed effect of SRAs on drying shrinkage was caused by coarser pore structure rather than by a decrease in surface tension of the pore solution. Since the decrease in surface tension does not necessarily lead to decrease in shrinkage, the application of capillary pressure theory in AAS can sometimes be an issue.
Keywords
Alkali-activated slag; Shrinkage; Admixture; Hydration; Capillary pressure; Surface tension
Authors
KALINA, L.; BÍLEK, V.; BARTONÍČKOVÁ, E.; KALINA, M.; HAJZLER, J.; NOVOTNÝ, R.
Released
10. 7. 2020
ISBN
0950-0618
Periodical
Construction and building materials
Year of study
248
Number
118620
State
United Kingdom of Great Britain and Northern Ireland
Pages from
1
Pages to
8
Pages count
URL
https://www.sciencedirect.com/science/article/pii/S0950061820306255
BibTex
@article{BUT162682, author="Lukáš {Kalina} and Vlastimil {Bílek} and Eva {Bartoníčková} and Michal {Kalina} and Jan {Hajzler} and Radoslav {Novotný}", title="Doubts over capillary pressure theory in context with drying and autogenous shrinkage of alkali-activated materials", journal="Construction and building materials", year="2020", volume="248", number="118620", pages="1--8", doi="10.1016/j.conbuildmat.2020.118620", issn="0950-0618", url="https://www.sciencedirect.com/science/article/pii/S0950061820306255" }