**1. Introduction**

Geopolymers—at the micro-level—are primarily composed of amorphous materials of the long matrix, cross-linked polymer chains of tetrahedral AlO4 and SiO4 units [1,2]. Geopolymers are usually dielectric materials due to the silica content and alkali metal ions, which could work as ionic conductors via an applied electric field [3,4]. Although pure geopolymers are electrically conductive due to the availability of water molecules and hydroxide in their composition, the open pore networks in the matrix produce conductivity [5,6]. Therefore, the introduction of filler materials becomes predominately necessary to improve electrical conductivity [7,8]. The most common additives preferred for the

**Citation:** Krishna, R.S.; Saha, S.; Korniejenko, K.; Qureshi, T.S.; Mustakim, S.M. Investigation of the Electrical Properties of Graphene-Reinforced Geopolymer Composites. *Mater. Proc.* **2023**, *13*, 34. https://doi.org/10.3390/ materproc2023013034

Academic Editors: Katarzyna Mróz, Tomasz Tracz, Tomasz Zdeb and Izabela Hager

Published: 15 February 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

fabrication of conductive geopolymer composites include carbon and metallic fillers, such as carbon fibres [5,9], nanotubes [10,11], graphite [8], graphene derivatives [7,8], steel fibres, etc.

Several research projects have been carried out to study and comprehend the influence of conductive fillers in the geopolymer matrix system. In one such examination, Payakaniti et al. optimized the inclusion of carbon fibre and stated that 0.5 wt.% provided superior electrical conductivity as well as mechanical properties [12,13]. Similar examinations were also carried out with carbon nanotubes [11,14]. The incorporation of 1 wt.% carbon nanotube in the geopolymer matrix enhanced the electrical conductivity performance by almost three times. Carbon nanotubes also reduce the electric resistance and impedance of associated composites [11,15]. Thus, it can be argued that the physical characteristics and the synthesis mechanisms of the conductive fillers play a vital role in the enhancement of geopolymer properties.

Research on the electrical properties of geopolymer composites is still a novel, diverse and challenging area, resulting in a lack of a universal approach and indicating the high complexity of the underlying problem [16]. Presently, one of the most promising multifunctional composites seems to be geopolymers incorporating graphene derivatives. The current study is therefore focused on the investigation of different effects of GO dosages (0, 0.1, 0.2, 0.3 and 0.4 wt.%) on the electrical properties and the dielectric response of fly-ash-based GRGC (graphene-reinforced geopolymer composite) specimens.
