Effects of graphene oxide on microstructure and mechanical properties of graphene oxide-geopolymer composites. (30th June 2020)

• Record Type: Journal Article
• Authors: Liu, Xinhao; Wu, Yueyue; Li, Maosen; Jiang, Jinping; Guo, Liang; Wang, Wenqiang; Zhang, Wensheng; Zhang, Zuhua; Duan, Ping
• Is Part Of: Construction & building materials. Volume 247(2020)
• Publication Date: 2020-06-30
• Subjects: Geopolymer -- Fly ash -- Graphene oxide -- Microstructure -- Mechanical properties; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.118544
• Languages: English
• ISSNs: 0950-0618

Abstract

Graphical abstract: Highlights: 28-day flexural strength of geopolymer increases by 25% with 0.30 wt% GO. GO/rGO accelerates the dissolution of fly ash microspheres and promotes the growth of geopolymer chain. Electron binding energy of O1s, Si2p and Al2p confirms the change in geopolymerization degree. The interfacial bonding mode of GO/rGO-geopolymer and reaction mechanism are proposed. Abstract: This work aims to examine the impact of graphene oxide (GO) and reduced graphene oxide (rGO) on mechanical properties and microstructure of fly ash (FA) based geopolymer. Different schemes were proposed to prepare GO/rGO-geopolymer composites. The chemical composition, microstructure and hydration degree of GO/rGO modified geopolymer were characterized by using FTIR, XRD, DTG, SEM, XPS and BET. The experimental results show that GO/rGO changes the microstructural composition and pore diameter distribution of geopolymer. The increased average electron binding energy of the tetrahedron of [AlSiO4 ] − or [AlSi3 O8 ] − leads to the acceleration of geopolymerization process. The decreased average pore volume and porosity confirms that GO/rGO accelerates the dissolution and hydration process of FA microspheres. GO and rGO exhibit different efficiency in promoting the hydration degree of geopolymer, which may be due to different functional groups and dispersion efficiency. Meanwhile, the flexural strength changes with addition of GO/rGO, which increases by 25% for the use of 0.30 wt% GO and 10% for the use of 0.10 wt% rGO. In general, GO and rGO are promising to promote the hydration of FA and increase the mechanical strength of geopolymer.