Resistivity Prediction Model for Basalt–Polypropylene Fiber-Reinforced Concrete

As a new cement-matrix composite material, fiber-reinforced concrete performs excellently in freeze–thaw resistance, tensile resistance, and seepage resistance. Since resistivity can be used to evaluate the performance of concrete, the resistivity of basalt–polypropylene fiber-reinforced concrete (BPFRC) was investigated in this study. Various parameters such as fiber type, fiber content, and water–binder ratio were also analyzed. The resistivity of the BPFRC was tested by an improved two-electrode alternating current (AC) method, and the differences in resistivity were analyzed using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). The results showed that adding fiber affected the resistivity of the BPFRC, and the basalt fiber had a more significant effect than the polypropylene fiber. The resistivity of the BPFRC was sensitive to the water–binder ratio, which showed a negative correlation. In addition, a 365-day resistivity model for the BPFRC was established by considering variables such as fiber, water–binder ratio, ambient temperature, and ambient relative humidity. The hydration equations of various cementitious materials were derived, and a time-varying resistivity model for the BPFRC was developed. Finally, the established resistivity model of the BPFRC lays a foundation for the further building of the relationship between resistivity and BPFRC performance.