Bernal, S.A., Provis, J.L., Brice, D.G. et al. (3 more authors) (2012) Accelerated carbonation testing of alkali activated binders significantly underestimates service life: The role of pore solution chemistry. Cement and Concrete Research, 42 (10). 1317 - 1326. ISSN 0008-8846
Abstract
The carbonation resistance of alkali-activated binders is often tested via accelerated test protocols designed for Portland cements, without questioning whether the tests replicate the mechanisms observed in service. Thus, validation of accelerated methods is required to enable realistic prediction of material performance. Changes in pore solution equilibria cause the formation of sodium bicarbonates during accelerated carbonation, compared with hydrous sodium carbonates in natural carbonation. This shifts the carbonation mechanism to favour more rapid reaction progress, to give a higher apparent degree of acceleration (compared to natural conditions) than in Portland cements. The pore solution pH under accelerated carbonation is significantly lower than at natural CO2 concentrations, leading to a falsely short predicted service life (time to expected corrosion of embedded steel), as natural CO2 concentrations appear not to reduce the pH below 10. Thus, accelerated carbonation testing is unduly aggressive towards alkali-activated binders, and test results must be cautiously interpreted.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2012 Elsevier. This is an author produced version of a paper subsequently published in Cement and Concrete Research. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/) |
Keywords: | Alkali-activated cement (D); Durability (C); Carbonation (C); Pore solution (B); Thermodynamic calculations (B) |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 12 Oct 2015 13:23 |
Last Modified: | 08 Nov 2016 21:30 |
Published Version: | https://doi.org/10.1016/j.cemconres.2012.07.002 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.cemconres.2012.07.002 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:86416 |