Structural health monitoring of concrete structures using electromechanical impedance technique

This paper describes the use of electromechanical impedance (EMI) method for monitoring concrete cube for a continuous period of “30 days”. The main objective is to study the gradual changes in the properties of concrete during the Curing process. For the purpose, a 150 × 150 × 150 mm
³
cubic concrete block was subjected to the test. Signatures were obtained using embedded and surface-bonded piezoelectric transducers (PZTs). The EM (admittance) signatures were processed using statistical indices like RMSD, for different periods of frequencies. But the conventional statistical tools did not serve the purpose in this situation. Hence, a new technique was devised (called RDSD) later. Also, various numerical calculations, sub-frequency domain analysis technique were implemented. After a number of trials, a suitable amount for number of sub-frequency domains was fixed (i.e. 10). Results from surface-bonded PZT were also compared to those from embedded PZT patch and based-on conclusions were deduced. The results show that EMI technique is well suitable for monitoring of curing progression of concrete structures.