Investigation of the viscoelastic evolution of reactive magnesia cement pastes with accelerated hydration mechanisms

Peng, Y. and Unluer, C. (2023) Investigation of the viscoelastic evolution of reactive magnesia cement pastes with accelerated hydration mechanisms. Cement and Concrete Composites, 142, 105191. (doi: 10.1016/j.cemconcomp.2023.105191)

Abstract

Viscoelasticity of reactive magnesia cement (RMC) pastes containing 3 different hydration agents (HCl, Mg(CH3COO)2 and MgCl2) were investigated. Amplitude sweep, frequency sweep and time sweep of RMC pastes were examined within 3 h of hydration. Time-dependent evolution of storage modulus, loss modulus, phase angle, and shear stress were recorded. Measurements of pH, isothermal calorimetry, XRD, TG-DTG and FTIR were used to analyze hydration reaction and products. Addition of hydration agents (HAs) accelerated the growth rate of storage modulus/loss modulus over time. MgCl2 demonstrated the greatest acceleration influence, also reflected in non-destructive structural build-up and buildability related to 3D printing applications. Addition of MgCl2 and HCl advanced the initial setting time of RMC pastes to 100–110 min, during which yield stress reached maximum, and decreased afterwards. Within 3 h of hydration, pastes containing MgCl2 revealed lowest pH, highest heat release and brucite concentration. HAs inclusion precipitated brucite away from MgO particles in the bulk solution, creating a bridge between MgO particles and enabling denser microscopic network structure.

• Item Type: Articles
• Additional Information: This study was funded by the Newton Fund Institutional Links project 623812328 provided by the British Council and China Scholarship Council (grant number: 202006370082).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Unluer, Dr Cise
• Authors: Peng, Y., and Unluer, C.
• College/School: College of Science and Engineering > School of Engineering
• Journal Name: Cement and Concrete Composites
• Publisher: Elsevier
• ISSN: 0958-9465
• ISSN (Online): 1873-393X
• Published Online: 21 June 2023
• Copyright Holders: Copyright © TheAuthor(s) 2023
• First Published: First published in Cement and Concrete Composites 142:105191
• Publisher Policy: Reproduced under a creative commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
311738		Climate resilient 3D-printable building components incorporating sustainable and low-cost materials (3D-PC)	Cise Unluer	British Council (UK) (BRCOU-UK)	623812328	ENG - Infrastructure & Environment