Effect of dispersion method of copper-plated steel fiber on piezoresistivity of cement mortar with waste ceramic powder

Waste ceramic powder can enhance the electrical properties of cement mortar, while copper-plated steel fibers possess excellent mechanical, electrical and corrosion-resistant properties. Introducing both materials into cement mortar can effectively improve cement mortar’s electrical conductivity and endow it with piezoresistivity. The dispersion states of copper-plated steel fibers in the cement mortar undoubtedly play a significant role in determining its electrical conductivity and piezoresistivity. Therefore, this study prepared copper-plated steel fiber reinforced cement mortar with waste ceramic powder (SFRCM) and investigated the effect of two dispersion methods of copper-plated steel fibers, namely direct pouring method and uniform sieving method, on the electrical resistivity and piezoresistivity of SFRCM. The results show that the uniform sieving method can effectively reduce the dispersion coefficient (the lower dispersion coefficient, the more uniform), and the reduction rate can be up to 29.47%, which effectively reduces the agglomeration of copper-plated steel fibers in the cement matrix. Compared with the direct pouring method, the uniform sieving method is more conducive to the reduction of DC resistivity of SFRCM, and the maximum reduction of DC resistivity is up to 13.90%. Under different test conditions, the uniform sieving method can endow SFRCM with better piezoresistivity compared with the direct pouring method, and the maximum improvement rate of strain sensitivity is up to 1,432.20%. From the mechanistic analysis, it is clear that with the uniform sieving method, the copper-plated steel fibers are more likely to form a uniformly distributed conductive network to improve the piezoresisitivity.