Characterisation of class F fly ash geopolymer pastes immersed in acid and alkaline solutions
Acid and alkaline resistance of class F fly ash based geopolymer pastes has been investigated. As prepared geopolymers showed high solubility in both strong alkali and acid solutions. Calcination of the fly ash based geopolymers at 600 C resulted in a decrease of amorphous component from 63.4 to 61....
| Main Authors: | , , , , |
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| Format: | Journal Article |
| Published: |
Elsevier BV
2011
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/32178 |
| Summary: | Acid and alkaline resistance of class F fly ash based geopolymer pastes has been investigated. As prepared geopolymers showed high solubility in both strong alkali and acid solutions. Calcination of the fly ash based geopolymers at 600 C resulted in a decrease of amorphous component from 63.4 to 61.6 wt.%. However, the solubility of the Al, Si and Fe ions in 14 M NaOH and 18% HCl after 5 days immersion decreased from 1.3 to 16-fold in comparison to as prepared geopolymer samples. Calcination of the geopolymers also resulted in a 30% reduction in compressive strength. Acid and alkali resistance of the geopolymers investigated strongly depends on mineralogical composition change of the calcined geopolymer. Partial crystallisation of non-reacted fly ash particles in the geopolymer decreases its solubility in acid and alkali solutions. |
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