Graphene geopolymer hybrid: a review on mechanical properties and piezoelectric effect

Abstract

A review on graphene geopolymers hybrid is presented, focusing on the mechanical properties and piezoelectric effect. The method and way of mixing graphene with geopolymers are discussed, including form of graphene that frequently being used by researchers which is graphene oxide (GO) and reduced graphene oxide (rGO). Type of geopolymers being focused in this paper is fly ash and kaolin. The flexural and compressive strength, fracture toughness and stiffness are highlighted in terms of mechanical properties after mixing with geopolymers. The piezoelectric effects on geopolymer is emphasized as graphene acted as conductive filler. Research findings revealed that graphene geopolymer hybrid displayed improvement in mechanical properties despite agglomeration and some defects that need to be rectified. Geopolymers such as metakaolin exhibited piezoelectric effect after being compressed cyclically with the migration of ions and by incorporating graphene nanoplateletes.