Graphene/fly ash geopolymeric composites as self-sensing structural materials

Abstract

The reduction of graphene oxide during the processing of fly ash-based geopolymers offers a completely new way of developing low-cost multifunctional materials with significantly improved mechanical and electrical properties for civil engineering applications such as bridges, buildings and roads. In this paper, we present for the first time the self-sensing capabilities of fly ash-based geopolymeric composites containing in situ reduced graphene oxide (rGO). Geopolymeric composites with rGO concentrations of 0.0, 0.1 and 0.35% by weight were prepared and their morphology and conductivity were determined. The piezoresistive effect of the rGO-geopolymeric composites was also determined under tension and compression. The Fourier transform infrared spectroscopy (FTIR) results indicate that the rGO sheets can easily be reduced during synthesis of geopolymers due to the effect of the alkaline solution on the functional groups of GO. The scanning electron microscope (SEM) images showed that the majority of pores and voids within the geopolymers were significantly reduced due to the addition of rGO. The rGO increased the electrical conductivity of the fly ash-based rGOgeopolymeric composites from 0.77 S m −1 at 0.0 wt% to 2.38 S m −1 at 0.35 wt%. The rGO also increased the gauge factor by as much as 112% and 103% for samples subjected to tension and compression, respectively.

Mechanical, thermal and electromagnetic properties of nanographite platelets modified cementitious composites

“…Moreover, extensive research endeavors demonstrated the potential of various nano carbon materials including carbon nanotubes, carbon nanofibres, and nano carbon black for enhancing/modifying cementitious materials [5][6][7][8][9][10]. However, at present the research on nanographite platelets (NGPs) modified cementitious composites just starts [1,[11][12][13][14][15].…”

Graphene nanoplatelet-fly ash based geopolymer composites

“…Recently, the incorporation of rGO in geopolymer composites showed that rGO particles enhance the flexural strength, Young's modulus and toughness of the geopolymeric composites because they display a 2-dimensional structure and strong chemical bonding with the matrix. Further, the addition of low amounts of rGO sheets into geopolymers improved the mechanical properties and reduced the overall porosity of the composite specimens [29,30]. To achieve this potential material enhancement, the development of an efficient and capable method for the mass production of graphene for industrial applications has attracted increased attention.…”

In Situ Processing of Graphene/Leucite Nanocomposite Through Graphene Oxide/Geopolymer

“…Geopolymers are synthesized under aqueous alkaline conditions, which are very suitable for dispersing and partially reducing GO . Saafi et al prepared rGO/fly ash geopolymeric composites with improved electrical and piezoresistive properties through in situ reduction of GO in NaOH solutions. The alkaline solution reduced the main functional groups of GO during processing.…”