Calibration of piezo-impedance transducers for strength prediction and damage assessment of concrete

This paper presents a new approach for the non-destructive evaluation of concrete, covering both strength prediction and damage assessment, using the electro-mechanical impedance technique. A new empirical method is proposed to determine in situ concrete strength non-destructively using admittance signatures of surface-bonded piezo-impedance transducers. This is followed by the 'identification' of appropriate impedance parameters for concrete. The identified parameters are found to be sensitive to structural damages as well as to concrete strength gain during curing. Comprehensive tests were conducted on concrete specimens up to failure to empirically calibrate the 'identified' system parameters with damage severity. An empirical fuzzy probabilistic damage model is proposed to quantitatively predict damage severity in concrete based on variation in the identified equivalent stiffness.