Influence of different additives on the rheology and microstructural development of MgO–SiO2 mixes

Kumar, S., Lei, J., Yang, E.-H. and Unluer, C. (2022) Influence of different additives on the rheology and microstructural development of MgO–SiO2 mixes. Composites Part B: Engineering, 235, 109784. (doi: 10.1016/j.compositesb.2022.109784)

Abstract

Development of alternative binder systems to be used in additive and automated manufacturing technologies is crucial for increasing the sustainability and productivity of the construction process. Advancements in this area facilitate shorter construction durations, enhanced resource efficiency and reduced construction waste; enabling complex, high-quality and functional designs that would not be possible with traditional methods. The novelty of this work involves the demonstration of the properties of a promising alternative binder, reactive MgO–SiO2 (RMS) binder, that can highlight its feasibility to be used in large-scale applications and the identification of the effects of different phosphate additives during this process. RMS mixes containing three different phosphate additives (sodium hexametaphosphate, trimetaphosphate and orthophosphate (OP)) were analyzed for their pH, reaction kinetics, workability, mechanical performance and rheological properties to reveal the influence of these additives on the properties of RMS mixes. These findings were supported by FTIR, 29Si MAS NMR and XRD measurements. The inclusion of OP in RMS binder systems increased the pH of solution, thereby improving the dissolution of silica and its reaction with Mg-phases and resulting in enhanced magnesium-silicate-hydrate (M-S-H) formation. These improvements in hydration mechanisms translated into better mechanical performance and rheological properties, which can correlate to desirable properties for 3D printing applications.

• Item Type: Articles
• Additional Information: The authors would like to the financial support from the 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
• Authors: Kumar, S., Lei, J., Yang, E.-H., and Unluer, C.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Composites Part B: Engineering
• Publisher: Elsevier
• ISSN: 1359-8368
• ISSN (Online): 1879-1069
• Published Online: 03 March 2022
• Copyright Holders: Copyright © 2022 Elsevier Ltd.
• First Published: First published in Composites Part B: Engineering 235:109784
• Publisher Policy: Reproduced in accordance with the publisher copyright policy