Electromagnetic interference shielding performance and piezoresistivity of multifunctional cement composites by adopting conductive aggregates

This study explores the application of multifunctional cement composites prepared with graphene-coated conductive aggregate (Gr@Ag) and carbon fiber (CF). The electromagnetic interference (EMI) shielding effectiveness, electrical conductivity, and piezoresistive performance of cement mortars were investigated by varying the aggregate to binder (a/b) ratio and CF content. It was found that the EMI shielding effectiveness of cement mortar was enhanced by 24.8 % with the a/b ratio increased from 1.0 to 2.5, reaching 20.07 dB with a 3 mm thickness specimen. This is accompanied by significant improvements in the electrical conductivity and piezoresistive performance of cement mortars. In addition, CFs were included in cement mortars to further improve the electrical performance. Results indicate that there exists a percolation threshold, beyond which extra CF additions did not lead to further increases in the conductivity of cement mortars. The present research has illustrated the novel approach of incorporating the EMI shielding functionality into cement composites by adopting conductive aggregates, expanding the functional and smart performances towards future applications.