Graphene nanoplatelets as an effective additive to tune the microstructures and piezoresistive properties of cement-based composites

Piezoresistive cement-based composites, as a type of self-sensing materials, are urgently needed for developing smart buildings. Herein the effect of graphene nanoplatelets (GNPs) on the pore structure, microstructure, mechanical and piezoresistive properties of cement mortar was investigated. A four-probe method was used to quantitatively assess the piezoresistive properties of the GNP-modified cement mortars under cyclic compressions. Results show that appropriate incorporations of GNPs in cement mortars can densify the microstructure and enhance the mechanical properties. The changes in electric conductivity against GNP content follow a percolation regime. The extents and rates of piezoresistive reactions have no simple correlations with GNP contents and loading levels. The mechanisms of piezoresistive reaction are associated with the elastic deformation and interfacial conductance between GNPs and material matrix. However, the interfacial conductance only works in moderate GNP contents. The results and findings of this study may pave a wide path for the uses of cement-based piezoresistive composites in developing self-health monitoring buildings and infrastructures in the future. (C) 2019 Elsevier Ltd. All rights reserved.