Study on the piezoresistivity and conductive network model of nickel-plated carbon fibre reinforced concrete

This study investigates the enhancement effect and modification mechanism of nickel-coated carbon fiber (NCF) on the piezoresistive performance of concrete. Nickel-coated carbon fiber concrete (NCFC) and conventional carbon fiber concrete (CFC) were prepared with varying fiber content (0.1%–0.4% vol). The study tested the static mechanical properties, electrical conductivity, and piezoresistive responses of concrete specimens under various loading regimes. Microstructural analysis was conducted, and the piezoresistive response mechanisms of both concrete specimens were thoroughly examined by establishing a conductive network model. Results indicate that NCF effectively enhances both the static mechanical properties and electrical conductivity of concrete, with a percolation threshold of 0.266%, significantly lower than that of CF. Under direct compressive loading, NCFC03 exhibited peak resistance change rates of −41.7% and strain sensitivity of 133.8, markedly outperforming specimens with equivalent CFC content. Under various cyclic loading conditions, NCFC demonstrated more stable and pronounced piezoresistive responses.