Influence of crack width on the stiffness recovery and self-healing of reactive magnesia-based binders under CO2-H2O conditioning

Ruan, S., Qiu, J., Yang, E.-H. and Unluer, C. (2021) Influence of crack width on the stiffness recovery and self-healing of reactive magnesia-based binders under CO2-H2O conditioning. Construction and Building Materials, 269, 121360. (doi: 10.1016/j.conbuildmat.2020.121360)

Abstract

This study investigated the healing efficiency and phase formations in pre-cracked reactive magnesia-based binders under CO2/water conditioning. Pre-loaded samples with various crack widths were subjected to a healing regime involving 10% CO2 and water for 10 cycles. The recovery of samples was assessed by resonance frequency measurements and optical microscopy observations. A relationship between crack width and type of healing phases was established via microstructural analysis and carbonation depth measurements. All samples achieved a complete stiffness recovery after a few healing cycles. The healed cracks revealed a higher stiffness than the surrounding matrix under reloading. The recovery of sample stiffness was associated with the densification of sample microstructure via the formation of hydrated magnesium carbonates (HMCs). Depending on the crack width and depth, two different types of HMCs (nesquehonite and hydromagnesite) were observed within the healed cracks, whose formation was influenced by pH, determined by the diffusion of CO2.

• Item Type: Articles
• Additional Information: The authors would like to acknowledge the financial support from the Singapore MOE Academic Research Fund Tier 1 (RG 95/16) and Singapore MOE Academic Research Fund Tier 2 (MOE2017-T2-1-087 (S)) for the completion of this research project.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Unluer, Dr Cise

Creator Roles

Unluer, C.: Funding acquisition, Investigation, Methodology, Project administration, Supervision, Validation, Writing – original draft, Writing – review and editing

• Authors: Ruan, S., Qiu, J., Yang, E.-H., and Unluer, C.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Construction and Building Materials
• Publisher: Elsevier
• ISSN: 0950-0618
• ISSN (Online): 1879-0526
• Published Online: 29 October 2020
• Copyright Holders: Copyright © 2020 Elsevier
• First Published: First published in Construction and Building Materials 269:121360
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher