Mechanical and microstructural changes in reactive magnesium oxide cement-based concrete mixes subjected to high temperatures

Hay, R., Dung, N.T., Lesimple, A., Unluer, C. and Celik, K. (2021) Mechanical and microstructural changes in reactive magnesium oxide cement-based concrete mixes subjected to high temperatures. Cement and Concrete Composites, 118, 103955. (doi: 10.1016/j.cemconcomp.2021.103955)

Abstract

This study investigated the mechanical, microstructural, and chemical changes in reactive MgO cement-based concrete cured under ambient and accelerated carbonation conditions, followed by exposure to high temperatures. The compressive strength of the ambient-cured samples increased from 10 to 30 MPa when subjected to up to 200 °C, induced by increased hydration of the remaining MgO. The accelerated formation of brucite at 50 °C also enhanced the compressive strength of the carbonated samples (58 vs. 65 MPa). A relatively stable performance (~56 MPa) was observed at temperatures ranging between 100 and 300 °C for the carbonated samples, associated with additional formation of brucite and transition of nesquehonite and hydromagnesite to artinite. The hydrated magnesium carbonates (HMCs) forming around brucite acted as barriers and delayed its dehydroxylation. The decomposition of brucite and HMCs at 400 °C caused a porous microstructure and a low residual strength (5–8 MPa) in both the ambient-cured and carbonated samples.

• Item Type: Articles
• Additional Information: The authors R. Hay and K. Celik thank the NYUAD Center for Interacting Urban Networks (CITIES), funded by Tamkeen under the NYUAD Research Institute Award CG001 and by the Swiss Re Institute under the Quantum Cities™ initiative for providing financial support to make this research possible and wish to express their gratitude to Dr. Abdullah Khalil and Core Technology Platform (CTP) experts, specifically Dr. James Weston and Dr. Liang Li, of New York University Abu Dhabi for their assistance with the experiment and data analyses. The authors N.T. Dung and C. Unluer would like to acknowledge the financial support from the Singapore-MIT Alliance for Research and Technology (SMART) Innovation Centre (ING1510112-ENG (IGN)) for the completion of this research project.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Unluer, Dr Cise
• Authors: Hay, R., Dung, N.T., Lesimple, A., Unluer, C., and Celik, K.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Cement and Concrete Composites
• Publisher: Elsevier
• ISSN: 0958-9465
• ISSN (Online): 1873-393X
• Published Online: 29 January 2021
• Copyright Holders: Copyright © 2021 Elsevier
• First Published: First published in Cement and Concrete Composites 118:103955
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher