Piezoresistive properties of ultra-high-performance fiber-reinforced concrete incorporating few-layer graphene.

• A self-sensing ultra-high-performance fiber-reinforced concrete (UHPFRC) is fabricated by incorporating few-layer graphene (FLG) • In the composite with 0.5 wt% FLG, the enhancement on compressive strength can reach to more than 25%. • The possible polarization and conduction mechanisms of the FLG/UHPFRC composites are proposed according to the dielectric polarization theory. • The FLG/UHPFRC composites exhibit distinct piezoresistive behavior from the ordinary cement-based sensors. Graphene nanomaterials have demonstrated tremendous prospects in the preparation of smart ultra-high-performance fiber-reinforced concrete (UHPFRC). However, few relevant researches are available on the piezoresistive behavior of the UHPFRC reinforced by few-layer graphene (FLG). In this research, the mechanical, electrical and mechanical–electrical behavior of the FLG/UHPFRC composites were investigated, and the possible polarization and conduction mechanisms of the FLG/UHPFRC composites were proposed. The findings showed that FLG was equably dispersed in the matrix, which enhanced the mechanical properties of the composite materials through the crack arresting effect, pinning effect and seeding effect, etc. FLG improved the conductivity and relative permittivity of the composites, but did not change the topology of the Nyquist plot. Moreover, the FLG/UHPFRC composites exhibited distinct piezoresistive behavior from ordinary cement-based sensors due to the coupling effect of the interfaces and microcracks. [ABSTRACT FROM AUTHOR]