In situ concrete structures inspection using a rolling ultrasonic scanner

A rolling ultrasonic scanner prototype was developed for concrete inspection by using a piezoelectric PVDF array transducer. The scanner operates in separate transmitter and receiver mode A multi-layer and multi-element transducer made by stacking pre-polarized PVDF films using an adhesive is a core part of the ultrasonic roller. With relatively short inspection time and good image quality obtained with our own adaptation of the SAFT algorithm, a large concrete area can be scanned. It is possible to use a wide range of operational frequencies due to the broadband characteristics obtained from the PVDF transducer. This feature is highly beneficial for concrete imaging where aggregates typically have a large variation in sizes and limits the image quality by enforcing a trade-off between penetration depth and resolution when choosing transducers