Development of more accurate methods for determining carbonation depth in cement-based materials
File(s)
Published version
Author(s)
Zhang, Kai
Yio, Marcus
Wong, Hong
Buenfeld, Nick
Type
Journal Article
Abstract
Measuring carbonation is increasingly important, especially for developing novel low-CO2 cements and carbon-capture technologies. This study shows for the first time, the feasibility and advantages of confocal Raman microscopy (CRM) for measuring carbonation depth in cement-based materials, providing high spatial resolution (down to <100 μm), by mapping CaCO3 and Ca(OH)2. Pastes and mortars of different binders (CEM I, 30 % PFA, 50 % GGBS) and w/b ratios (0.45, 0.60) exposed to natural (440 ppm CO2) and accelerated carbonation (4 % CO2) at 65 % RH, 21 °C for up to 3 months were tested. CRM shows a sharp carbonation front, without the transition zone commonly supposed. Carbonation depths measured with image analysis of CRM-CaCO3 maps and phenolphthalein-treated surfaces are in excellent agreement, however the latter is less reliable for depths <5 mm. Profile-based methods (TGA, XRD, FTIR, RS and BSE) systematically over-estimate carbonation depth; a simple method to correct this error is proposed.
Date Issued
2024-01
Date Acceptance
2023-10-23
Citation
Cement and Concrete Research, 2024, 175
ISSN
0008-8846
Publisher
Elsevier
Journal / Book Title
Cement and Concrete Research
Volume
175
Copyright Statement
© 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
http://dx.doi.org/10.1016/j.cemconres.2023.107358
Publication Status
Published
Article Number
107358
Date Publish Online
2023-10-28