Herterich, JA, Black, L and Richardson, I (2015) Microstructure and Phase Assemblage of Low-Clinker Cements during Early Stages of Carbonation. In: Black, L and richardson, I, (eds.) The 14th International Congress on the Chemistry of Cement (ICCC 2015)Abstract Book Volume 1. International Congress on the Chemistry of Cement (ICCC), 13-16 Oct 2015, Beijing, China.
Abstract
This study investigates the effects of carbonation following short curing periods (72 hours) on CEMI and composite cement systems (30% PFA, 30% & 60% GGBS). Modifications in carbonation behaviour were observed compared to ‘idealised’/28 day lab cured samples and accelerated carbonation testing. Carbonation of Ca(OH)2 and C-S-H did not occur simultaneously, with decalcification of C-S-H only beginning once no more Ca(OH)2 was available. Decalcification and dealumination of the C-S-H phase occurred following exposure to ambient [CO2], and CaCO3 microcrystals were observed in the outer product (Op) regions only. A reduction in the Ca/Si ratio of the Ip C-S-H appears to be a result of migration of the Ca ions, driven by a concentration gradient. Furthermore, the rate and extent of carbonation and the nature of the carbonate species formed is dependent on the level of replacement, the replacement material and the degree of hydration. Predominantly calcite was the polymorph formed, however some vaterite was also observed in the samples containing PFA. STA data indicated the production of a crystalline carbonate phase resulting from carbonation of Ca(OH)2 and a metastable, poorly crystalline carbonate phase resulting from the carbonation of the C-S-H phase.
Metadata
Item Type: | Proceedings Paper |
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Authors/Creators: |
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Editors: |
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Keywords: | Early age; Carbonation; Phase assemblage; Morphology |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Civil Engineering (Leeds) > Institute for Resilient Infrastructure (Leeds) |
Funding Information: | Funder Grant number Nanocem Network .NanoCem Consortium |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 May 2016 10:12 |
Last Modified: | 16 Jan 2018 09:36 |
Status: | Published |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:96988 |