Influence of Carbonation on the Electrical Conductivity of Graphene/Cement Composite

The electrical conductivity of graphene/cement composite before and after carbonation was tested by a four-electrode method. The General Effective Media equation was adopted to fit the experiment results. EIS (electrochemical impedance spectroscopy) was employed to study the effect of carbonation on conductivity of graphene/cement composite. The mechanism was analyzed by SEM (scanning electron microscopy). It is revealed that electrical conductivity increases with increasing carbonation depth when the graphene content is less than 2.0%. In this case, the electrical conductivity of composite depends on cement matrix which can be enhanced by carbonation product through filling pores. When the graphene content exceeds 3.3%, the electrical conductivity decreases with increasing carbonation depth. The conductive path is mainly formed by graphene chains which can be broke by carbonation product. The GEM (General Effective Media) equation fits the experimental results well and can be used to calculate the electrical conductivity of graphene/cement composite after carbonation.