A new approach for constructing UHPC conductive pathways: Oriented deposition of conductive hydration products

Regulating the resistivity of ultra-high-performance concrete (UHPC) infrastructure is crucial for endowing UHPC with intelligence and multifunctionality. In this study, we proposed a new approach to enhance the electrical conductivity of UHPC via high-temperature electric induction. When the temperature of electric-cured UHPC was heated to 90–130 °C, the resistivity dropped sharply. After electric curing, the resistivity of UHPC was significantly reduced from 8.7 MΩ·cm to 537.18 Ω·cm compared to that of steam-cured UHPC. It was confirmed that the tunneling effect and dielectric breakdown were the main reasons for the sudden resistivity drop during electric curing. Moreover, electrochemical impedance spectroscopy (EIS) and model experiments revealed the oriented deposition of new conductive products within the UHPC matrix. This approach also strengthened UHPC in 3 h comparable to 3-day steam curing of 90 °C. This work opened up a novel path in constructing effective conductive networks of cement-based materials.