Gevaudan, JP, Craun, Z and Srubar III, WV (2021) Sulfuric acid degradation of alkali-activated metakaolin cements supplemented with brucite. Cement and Concrete Composites, 121. 104063. ISSN 0958-9465
Abstract
This study investigated the effect of alkali content (Na:Al = 0.86 and 1.39) and brucite (i.e., Mg(OH)2) mineral addition on the sulfuric acid resistance of alkali-activated metakaolin (i.e., geopolymers). Geopolymers consist primarily of a sodium-stabilized aluminosilicate hydrate (N-A-S-H) framework. Results demonstrate that higher alkali contents and brucite addition improve the acid resistance of N-A-S-H, as evidenced by reduced dealumination and Si and Na leaching upon exposure to acid. These results are mechanistically explained by increased retention of Mg+2 within the microstructure and increased Mg–Al interaction upon acid exposure. Higher Mg+2 retention and increased Mg–Al coupling together provide empirical evidence of polyvalent cationic stabilization—a mechanism involving polyvalent cations (e.g., Mg+2) that stabilize the N-A-S-H binder by arresting acid-induced electrophilic attack. Results further illustrate that brucite addition, especially at high-alkali content formulations, reduces micro-scale porosity while increasing the proportion of gel pores (<5 nm), which suggests that increased tortuosity of gel pores may aid in Mg+2 retention and promote the increased Mg–Al coupling observed herein.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 Elsevier Ltd. All rights reserved. This is an author produced version of an article, published in Cement and Concrete Composites. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Alkali-activated materials; Geopolymers; Sulfuric acid; Mineral admixtures; Brucite |
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) |
Funding Information: | Funder Grant number EU - European Union 839436 |
Depositing User: | Symplectic Publications |
Date Deposited: | 26 May 2021 12:17 |
Last Modified: | 15 Apr 2022 00:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.cemconcomp.2021.104063 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:174506 |