Controlling the Formation of Electroactive Graphene-Based Cementitious Composites: Towards Structural Health Monitoring of Civil Structures

The development of composites combining multiple components each one imparting a specific function to the ensemble is highly sought after for disruptive applications in chemistry and materials science, with a particular importance for the realization of smart structures. Here, we report on the development of an unprecedented multifunctional cementitious composite incorporating reduced graphene oxide (rGO). By design, this material features significantly enhanced electrical properties while retaining the excellent cement's hydration and microstructure. The multiscale investigation on the chemical and physical properties of the dispersion made it possible to establish an efficient preparation protocol for rGO aqueous dispersion as well as rGO-based cementitious composites using a commercial poly(carboxylate ether)-based superplasticizer. The conduction mechanisms within the matrix of rGO containing mortars were unraveled by electrochemical impedance spectroscopy revealing conductive paths originating from bulk cement matrix and rGO nanosheets in composites with rGO loadings as low as 0.075 wt. %. For this rGO loading, we observed the reduction of the resistivity of bulk cement mortar layers from 18.3 M omega cm to 2.8 M omega cm. Moreover, the addition of 0.2 wt. % of rGO resulted in the formation of rGO conductive paths with the resistivity of 51.1 k omega cm. These findings represent a major step forward towards the practical application of graphene-based materials in structural health monitoring of concrete structures. Multifunctional rGO-based cement composite featuring remarkably enhanced electrical properties was developed. Simple and efficient method for obtaining homogeneous and stable rGO dispersion in cement composites was established. Electrochemical impedance spectroscopy was applied to investigate the conduction mechanisms within rGO-based cement mortar and new electrical equivalent circuit was proposed.image

Automated summary

The development of a multifunctional cement composite based on reduced graphene oxide (rGO) with enhanced electrical properties is reported. A simple and efficient method for obtaining a homogeneous and stable rGO dispersion in cement composites was established. Electrochemical impedance spectroscopy was applied to investigate the conduction mechanisms within the rGO-based cement mortar, revealing the formation of conductive paths from the bulk cement matrix and rGO nanosheets. This research represents a major advancement in the practical application of graphene-based materials for structural health monitoring of concrete.