Freeze-thaw durability of red mud slurry-class F fly ash-based geopolymer: Effect of curing conditions

[Display omitted] •RMSFFA geopolymers showed good F-T resistance after 50F-T cycling.•50 °C and 14-day curing are more favorable conditions for better F-T resistance.•Micro-cracks and gel dissolution likely caused RMSFFA’s mechanical deterioration. Freeze-thaw (F-T) durability of geopolymers synthes...

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Bibliographic Details
Published in:Construction & building materials 2019-08, Vol.215, p.381-390
Main Authors: Zhao, Mengxuan, Zhang, Guoping, Htet, Khant Win, Kwon, Minji, Liu, Chunyuan, Xu, Yan, Tao, Mingjiang
Format: Article
Language:English
Subjects:
BET
Chemical properties
Fly ash
Freeze-thaw resistance
FTIR
Geopolymer
Infrared spectroscopy
Red mud slurry
Spectroscopy
XRD
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Summary:[Display omitted] •RMSFFA geopolymers showed good F-T resistance after 50F-T cycling.•50 °C and 14-day curing are more favorable conditions for better F-T resistance.•Micro-cracks and gel dissolution likely caused RMSFFA’s mechanical deterioration. Freeze-thaw (F-T) durability of geopolymers synthesized from the mixture of red mud slurry-Class F fly ash (RMSFFA) was investigated in this study, with an emphasis on the influence of curing conditions (i.e., curing time and curing temperature). F-T durability was evaluated on the basis of the sustained mechanical strength of RMSFFA geopolymer specimens after subjected to 50F-T conditioning cycles. The change in their chemical bonding, mineralogy, and pore characteristics at various F-T conditioning cycles was examined with Fourier transform infrared spectroscopy, X-ray diffractometer, and Brunauer–Emmett–Teller testing, respectively, to reveal the underlying processes during F-T conditioning. The results of both mechanical strength and microstructural characterization indicate that curing conditions influence F-T resistance of RMSFFA geopolymer samples through affecting their strength development. For 14-day cured RMSFFA samples at 50 °C, they experienced further geopolymerization at the early stage of F-T conditioning but the partial dissolution of geopolymer gel at the later stage of F-T conditioning. For 28-day cured samples at 50 °C, only the partial dissolution of geopolymer gel was likely to occur during the F-T conditioning because the strength development was likely to complete prior to the conditioning.
ISSN:0950-0618
1879-0526
DOI:10.1016/j.conbuildmat.2019.04.235