Effect of rGO/GNP on the electrical conductivity and piezoresistance of cement-based composite subjected to dynamic loading

Abstract

Graphene has good compatibility with cement-based materials. It can be introduced into cement to produce cement-based composite with electrical conductivity and loading sensitivity, and can effectively monitor the internal state of concrete components under stresses such as compression, bending, and tension. The electrical properties of such cement-based composites vary with the type and doping level of graphene. In this study, two types of reduced graphene oxide (rGO) with varying oxygen contents and two types of graphene nanoplates (GNPs) with varying sheet sizes were selected, and the conductivity and piezoresistive properties of the rGO/GNP cement-based composites subjected to cyclic compressive and tensile stress were investigated. Both tunnelling effect and percolation phenomena simultaneously played important roles in conductivity and electromechanical properties of graphene cement-based composite. The rGO/GNP cement-based composites exhibited excellent piezoresistive characteristics under compressive or tensile stress and stable repeatability. The cement-based composites filled with high oxygen content graphene (rGO-HO) or large sheet size graphene (GNP-L) has a larger stress sensitivity coefficient. This study reveals the great potential of graphene for real-time and in situ health monitoring of concrete structures. The excellent loading response ability of graphene has laid the foundation for the development of new smart materials based on graphene cement, which is of great significance for expanding the use of graphene and for the intelligent of traditional building materials.