Formation of carbonate phases and their effect on the performance of reactive MgO cement formulations

Dung, N.T., Lesimple, A., Hay, R., Celik, K. and Unluer, C. (2019) Formation of carbonate phases and their effect on the performance of reactive MgO cement formulations. Cement and Concrete Research, 125, 105894. (doi: 10.1016/j.cemconres.2019.105894)

Abstract

This study investigated the formation of different phases and their influence on the microstructural and mechanical development of carbonated reactive MgO cement formulations. Hydrated magnesium carbonates (HMCs) were identified and quantified via XRD, TG-DTG and SEM. Visual observations of the 3D internal structure at different depths were performed by X-ray computed tomography and confocal Raman microscopy. Elastic modulus of different components was obtained by nano-indentation. The expansive formation of HMCs led to dense microstructures composed of well-connected carbonate networks. The transition of artinite to hydromagnesite/nesquehonite was observed over time. The initial formation of a dense carbonate layer on sample surface inhibited continuous diffusion of CO2, resulting in a slower strength development at later ages. Despite this limitation, the continuation of hydration and evolution of carbonate morphology led to 28-day strengths of 60 MPa in concrete samples, supported by the higher elastic modulus of HMCs than brucite (19.4 vs. 2.5 GPa).

• Item Type: Articles
• Additional Information: N.T. Dung and C. Unluer would like to acknowledge the financial support from the Singapore-MIT Alliance for Research and Technology Centre (ING1510112-ENG (IGN)) for the completion of this research project.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Unluer, Dr Cise
• Authors: Dung, N.T., Lesimple, A., Hay, R., Celik, K., and Unluer, C.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Cement and Concrete Research
• Publisher: Elsevier
• ISSN: 0008-8846
• ISSN (Online): 1873-3948
• Published Online: 06 September 2019