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Chloride transport resistance of alkali-activated concrete exposed to combined chloride, sulfate and carbonation environment
https://orcid.org/0000-0002-3774-8202
Highlights Carbonation accelerates the deterioration of AAFA under chloride-sulfate attack condition. The deterioration of AAFS caused by carbonation was less serious compared with AAS. Sulfate coupling reduces the chloride transport of AAFS suffered chloride-carbonation attack. The gap between AAFA and AAS in chloride transport became smaller with exposure time. AAFS shows the best long term performance exposed to chloride-sulfate-carbonation attack.
Abstract The chloride transportation in alkali-activated fly ash (AAFA), alkali-activated slag (AAS) and alkali-activated fly ash/slag (AAFS) concrete exposed to the environments of single chloride and combined of chloride, sulfate and carbonation were investigated. The iodide migration, chloride diffusion and capillary absorption tests were carried out before and after exposure, as well as the analysis of their microstructure and compositions. It was found that the initial chloride transport of AAFA concrete was the highest but decreased gradually with the increase of exposure period. For AAFA and AAFS specimens with a relatively lower strength, chloride and sulfate salt crystallization led to the surface spalling and strength reduction. The coupling of carbonation would further accelerate the deterioration of AAFA, but the inhibitory effect was acted for AAFS specimen. Although the appearance of AAS specimens had little change under various aggressive environments, carbonation led to the decalcification of C-(A)-SH gels and deterioration of pore structure, both the porosity and the harmful 10–50 nm pores content of the specimens were higher compared with that before exposure, and their chloride transport increased with time. However, the deterioration of AAFS specimens resulted from carbonation was less serious, due to the formation of C-(N)-ASH gels with a higher degree of cross-linking and polymerization, thereby it had the best long term performance under the combined environment of chloride, sulfate and carbonation.
Chloride transport resistance of alkali-activated concrete exposed to combined chloride, sulfate and carbonation environment
https://orcid.org/0000-0002-3774-8202
Highlights Carbonation accelerates the deterioration of AAFA under chloride-sulfate attack condition. The deterioration of AAFS caused by carbonation was less serious compared with AAS. Sulfate coupling reduces the chloride transport of AAFS suffered chloride-carbonation attack. The gap between AAFA and AAS in chloride transport became smaller with exposure time. AAFS shows the best long term performance exposed to chloride-sulfate-carbonation attack.
Abstract The chloride transportation in alkali-activated fly ash (AAFA), alkali-activated slag (AAS) and alkali-activated fly ash/slag (AAFS) concrete exposed to the environments of single chloride and combined of chloride, sulfate and carbonation were investigated. The iodide migration, chloride diffusion and capillary absorption tests were carried out before and after exposure, as well as the analysis of their microstructure and compositions. It was found that the initial chloride transport of AAFA concrete was the highest but decreased gradually with the increase of exposure period. For AAFA and AAFS specimens with a relatively lower strength, chloride and sulfate salt crystallization led to the surface spalling and strength reduction. The coupling of carbonation would further accelerate the deterioration of AAFA, but the inhibitory effect was acted for AAFS specimen. Although the appearance of AAS specimens had little change under various aggressive environments, carbonation led to the decalcification of C-(A)-SH gels and deterioration of pore structure, both the porosity and the harmful 10–50 nm pores content of the specimens were higher compared with that before exposure, and their chloride transport increased with time. However, the deterioration of AAFS specimens resulted from carbonation was less serious, due to the formation of C-(N)-ASH gels with a higher degree of cross-linking and polymerization, thereby it had the best long term performance under the combined environment of chloride, sulfate and carbonation.
Chloride transport resistance of alkali-activated concrete exposed to combined chloride, sulfate and carbonation environment
https://orcid.org/0000-0002-3774-8202
Highlights Carbonation accelerates the deterioration of AAFA under chloride-sulfate attack condition. The deterioration of AAFS caused by carbonation was less serious compared with AAS. Sulfate coupling reduces the chloride transport of AAFS suffered chloride-carbonation attack. The gap between AAFA and AAS in chloride transport became smaller with exposure time. AAFS shows the best long term performance exposed to chloride-sulfate-carbonation attack.
Abstract The chloride transportation in alkali-activated fly ash (AAFA), alkali-activated slag (AAS) and alkali-activated fly ash/slag (AAFS) concrete exposed to the environments of single chloride and combined of chloride, sulfate and carbonation were investigated. The iodide migration, chloride diffusion and capillary absorption tests were carried out before and after exposure, as well as the analysis of their microstructure and compositions. It was found that the initial chloride transport of AAFA concrete was the highest but decreased gradually with the increase of exposure period. For AAFA and AAFS specimens with a relatively lower strength, chloride and sulfate salt crystallization led to the surface spalling and strength reduction. The coupling of carbonation would further accelerate the deterioration of AAFA, but the inhibitory effect was acted for AAFS specimen. Although the appearance of AAS specimens had little change under various aggressive environments, carbonation led to the decalcification of C-(A)-SH gels and deterioration of pore structure, both the porosity and the harmful 10–50 nm pores content of the specimens were higher compared with that before exposure, and their chloride transport increased with time. However, the deterioration of AAFS specimens resulted from carbonation was less serious, due to the formation of C-(N)-ASH gels with a higher degree of cross-linking and polymerization, thereby it had the best long term performance under the combined environment of chloride, sulfate and carbonation.
Chloride transport resistance of alkali-activated concrete exposed to combined chloride, sulfate and carbonation environment
Wang, Xiaobo (Autor:in) / Kong, Lijuan (Autor:in) / Zhao, Wenjing (Autor:in) / Liu, Yazhou (Autor:in)
07.01.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
| Taylor & Francis Verlag | 2025
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Resistance of alkali-activated slag concrete to carbonation
| British Library Online Contents | 2001