Journal article
Influence of graphene oxide in a chemically activated fly ash
Fuel (Guildford), Vol.226, pp.644-657
08/15/2018
Handle:
https://hdl.handle.net/2376/120067
Abstract
•GO can affect the distribution of hydration precursors as a functional material.•GO increases the polymerization degree of fly ash geopolymer.•GO promotes the formation of low quartz and jennite-like hydrates.•GO improves the mechanical strength of fly ash geopolymer notably.
To divert fly ash from hazardous waste stream to beneficial uses, this work aims to improve the solidification of fly ash as a geopolymer material by using graphene oxide (GO). The hydration precursors, morphology, elemental composition, mineralogy, chemical structure and ordering of GO-modified fly ash geopolymer were investigated by means of Raman spectroscopy, SEM/BSE, EMPA, XRD/TGA and 29Si/27Al MAS-NMR, respectively, to unravel the role of GO. The experimental results suggest that GO regulated the Ca/Si, Si/Al and Ca/(Si + Al) mole ratios to facilitate the formation of fly ash hydrates with improved mechanical strength, as GO showed the ability to selectively affect the distribution of different hydration precursors. GO also promoted the formation of low quartz and jennite-like hydrates. Overall, the 28-day compressive strength of fly ash geopolymer (w/b = 0.35) in this study was improved by 23% (from 33.6 MPa to 41.4 MPa) with GO admixed at 0.02% by mass of fly ash. The NMR study showed that GO improved the polymerization degree of fly ash geopolymer by increasing the total Q3 and Q4 Si-tetrahedrons, which suggests potential for improving the immobilization of heavy metals in fly ash.
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Details
- Title
- Influence of graphene oxide in a chemically activated fly ash
- Creators
- Gang Xu - Laboratory for Advanced & Sustainable Cementitious Materials, Department of Civil & Environmental Engineering, Washington State University, Pullman, WA, United StatesJing Zhong - School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, ChinaXianming Shi - Laboratory for Advanced & Sustainable Cementitious Materials, Department of Civil & Environmental Engineering, Washington State University, Pullman, WA, United States
- Publication Details
- Fuel (Guildford), Vol.226, pp.644-657
- Academic Unit
- Civil and Environmental Engineering, Department of
- Publisher
- Elsevier Ltd
- Identifiers
- 99900612707601842
- Language
- English
- Resource Type
- Journal article