To further evaluate the corrosion conditions of steel bars in RC structures

the monitoring and location technology for the corroded steel bars in RC beams was investigated based on piezoelectric sensors. Firstly

three pairs of piezoelectric lead zirconate titanate (PZT) sensors were arranged on the surface of the steel bar

then the monitored signals were processed by Radix-4 FFT

and the frequency spectrum features were extracted to figure out the development trend of the corrosion process. Meanwhile

the applicability of the PZT-based monitoring method for the overall corrosion process of steel bars was verified. Secondly

for the purpose of locating the corrosion positions of the steel bar

the weight function of the probabilistic imaging method was modified to obtain the position image of the corroded steel bar. Finally

the peak signal in the frequency domain was analyzed

and the relationship between the damage factor (FDI) and the corrosion rate was established to quantify the corrosion degree of the steel bar. Results show that the corrosion process of steel bars in RC beams could be divided into three phases: depassivation phase

debonding phase

and failure phase; the proposed damage factor (FDI) could effectively depict the three phases in the corrosion process of steel bars and quantify the corrosion rate of steel bars; the probabilistic imaging method could realize whole-process monitoring and analyze the corrosion positions of the steel bars. It indicates that the monitoring technology and the probabilistic imaging method can accurately monitor the overall process and locate the corrosion positions of steel bars in RC structures. The relationship between each phase of the whole process and the damage factor (FDI) can quantify the steel corrosion rate

which can provide technical support for the safety assessment of RC structures.