Temperature and loading effects of embedded smart piezoelectric sensor for health monitoring of concrete structures

• Novel embedded piezoelectric sensor for SHM of concrete structure was developed.
• Influence of temperature on EMI method were studied at different frequency ranges.
• The electromechanical impedance responds differently to load from orthotropic direction.

A kind of embedded impedance-based piezoelectric sensor was fabricated by using mixture of cement powder and epoxy resin as packaging layer. Effects of temperature and load on impedance and conductance spectra of the sensor were investigated. The results show that the baseline of conductance spectra shifts with increasing temperature, and the resonance peaks in the conductance spectra show obvious temperature dependence. The impedance spectra of the embedded sensor under external load from different direction was discussed. The results indicate that the sensor is sensitive to the initial load when the external load is parallel to the thickness direction of the sensor. When the load is along the planar direction of the sensor, the impedance spectra of the sensor show good correlation with the load variation. The root mean square deviation (RMSD) index was also employed here to intuitively indicate the impedance variation of the embedded PZT sensor under temperature and load.