Synthesis of Highly-Dispersed Graphene Oxide Nanoribbons-Functionalized Carbon Nanotubes-Graphene Oxide (GNFG) Complex and Its Application in Enhancing the Mechanical Properties of Cementitious Composites.

Peiqi Li,Sungwun Her,Junxing Liu,Erfan Zal Nezhad,Sungchul Bae,Seungmin Lim

doi:10.3390/nano11071669

Abstract

In this study, a graphene oxide nanoribbons–functionalized carbon nanotubes–graphene oxide (GNFG) complex was hydrothermally synthesized as a nanomaterial for reinforcing cementitious composites, using a modified Hummers’ method. Three types of components existed in the GNFG: Type I, the functionalized carbon nanotubes–graphene oxide nanoribbons (FCNTs–GNR); and types II and III are graphene oxide (GO) and functionalized carbon nanotubes (FCNTs), respectively, which exist independently. The dispersivity of GNFG and its effects on the mechanical properties, hydration process, and microstructures of cement pastes were evaluated, and the results were compared with those using cement pastes incorporating other typical carbon nanomaterials. The results demonstrated that dispersion of GNFG in aqueous solutions was superior to that of the CNTs, FCNTs, and GO/FCNTs mixture. Furthermore, the highly-dispersed GNFG (0.05 wt.%) improved the mechanical properties of the cement paste after 28 days of hydration and promoted the hydration of cement compared to CNTs, GO, and GO/FCNTs mixture (0.05 wt.%). The results in this study validated the feasibility of using GNFG with enhanced dispersion as a new nano-reinforcing agent for various cementitious systems.

Highlights

Since the development of Portland cement in 1824, it has gradually become the most extensively used building material worldwide due to its excellent performance and low cost [1]
Portland cement is usually applied as a binder to form cementitious materials, including concrete, along with other aggregates
Owing to the brittleness and lack of flexural/tensile strength of cementitious materials, many studies have focused on improving its mechanical strength

Summary

Introduction

Since the development of Portland cement in 1824, it has gradually become the most extensively used building material worldwide due to its excellent performance and low cost [1]. Xue et al [7] and Cao et al [8] reported that the fiber exhibited various reinforcement effects on cementitious materials due to their different types and lengths. These fibers can improve the tensile strength and toughness of cementitious materials, delaying the transformation of microcracks into microforms, they cannot constrain the development of microcracks [9]. Nanomaterials, such as nano-silica, nano-titanium dioxide (TiO2 ), carbon nanotubes (CNTs), and graphene oxide (GO), have been found to improve the mechanical properties of cementitious materials and hinder the spread of microcracks [10]

Methods

Results

Conclusion