Low-cost biphasic DC data acquisition for monitoring cementitious self-sensing materials

Self-sensing materials possess the capability to monitor their own conditions, offering promising solutions for structural health monitoring (SHM) in civil and mechanical infrastructure. By altering the matrix properties of materials through doping with fillers such as carbon fibers, carbon black, and multiwall carbon nanotubes, these materials exhibit piezoresistive behavior. This enables the measurement of electrical properties like impedance, capacitance, and resistance, which correlate with the material’s structural health. However, DC measurements often reveal a time-based drift in resistance due to material polarization. This work presents hardware developments for a biphasic data acquisition system to address the phenomenon of drift. The system leverages the theory that the drift in carbon-based self-sensing materials is due to material polarization, mitigated by reversing the excitation current direction. This approach effectively eliminates observable drift, ensuring accurate SHM assessments.