Carrot-based covalently bonded saccharides as a new 2D material for healing defective calcium-silicate-hydrate in cement:Integrating atomistic computational simulation with experimental studies

Chi, Yin and Huang, Bo and Saafi, Mohamed and Ye, Jianqiao and Lambert, Colin (2020) Carrot-based covalently bonded saccharides as a new 2D material for healing defective calcium-silicate-hydrate in cement:Integrating atomistic computational simulation with experimental studies. Composites Part B: Engineering, 199. ISSN 1359-8368

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Abstract

Concrete is currently produced at a rate of 20 billion tonnes per year and contributes 5-10% of mankind’s CO2 production. If the strength of the calcium-silicate-hydrate (C-SH), the main binding material of concrete, could be improved, the volume of cementitious material needed for a given structure would be reduced and its environmental impact would be decreased. Here, we show that the constitutive behavior of C-S-H can be improved significantly by complexation with carrot-based cellulose nanosheets (CNSs). This environmentally friendly, reinforcing material heals the defective microstructure of C-S-H, which is responsible for structural deformation and failure at larger length scales. CNSs are built from repeating saccharide units that are covalently linked by a β-1-4 glycosidic (C-O-C) bond. The CNSs show remarkable affinity to C-S-H due to the interfacial Ca-O coordination and H-bond interaction. The functional groups on the surface of the CNS sheet act as a root network, cross-linking the neighboring silicate calcium layers and inhibiting the water dynamics at the silicate nanochannel, thereby significantly improving the interfacial properties of the C-SH/CNS hybrid structure. The macro experimental results show that the mechanical properties of the composites increase with increasing the concentration of CNSs up to 0.4-wt%. At 28 days and CNS concentration of 0.20-wt%, the flexural strength increases by about 23.2% and the compressive strength increases by about 17.5%. The C-S-H/CNS composites show significant enhancement in strength, stiffness and ductility, and provide a foundation for the development of new high-performance construction materials with lower carbon footprint.

Item Type:
Journal Article
Journal or Publication Title:
Composites Part B: Engineering
Additional Information:
This is the author’s version of a work that was accepted for publication in Composites Part B: Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Composites Part B: Engineering, 199, 2020 DOI: 10.1016/j.compositesb.2020.108235
Subjects:
ID Code:
145822
Deposited By:
Deposited On:
29 Jul 2020 15:35
Refereed?:
Yes
Published?:
Published
Last Modified:
01 Dec 2020 08:13