Electrically conductive behaviors and mechanisms of short-cut super-fine stainless wire reinforced reactive powder concrete

The incorporation of short-cut super-fine stainless wire (SSSW) is an effective way to improve the electrically conductive and self-sensing capability of reactive powder concrete (RPC) composed of cement, silica fume, fly ash and silica sand. The conductive characteristics of SSSW reinforced RPC and their responses to external loading are investigated. The conductive mechanisms are revealed through electrochemical impedance spectroscopy and intrinsic conductivity analysis. The results show that the percolation occurs and polarization disappears in SSSW reinforced RPC containing 0.5 vol% of SSSW in diameter of 20 μm, and the electrical resistivity of which measured by using four-electrode-DC method drops to 44 Ω cm from 20.8 × 104 Ω cm. The gauge factor of RPC reinforced with SSSW in diameter of 8 μm can reach up to 22.5, 94.9 and 43.6 under cyclic compression, monotonic compression and flexure, respectively. The conductivity of SSSW reinforced RPC mainly depends on the formation of SSSW conductive network.