Detection of rebars in concrete using advanced ultrasonic pulse compression techniques

•Ultrasonic testing has been used to inspect concrete samples.•The use of pulse compression technique and coded signals has been proposed.•A novel post processing of the acquired signals has been proposed.•The proposed combination has allowed signals from reinforcement bar to be detected. A pulse compression technique has been developed for the non-destructive testing of concrete samples. Scattering of signals from aggregate has historically been a problem in such measurements. Here, it is shown that a combination of piezocomposite transducers, pulse compression and post processing can lead to good images of a reinforcement bar at a cover depth of 55 mm. This has been achieved using a combination of wide bandwidth operation over the 150–450 kHz range, and processing based on measuring the cumulative energy scattered back to the receiver. Results are presented in the form of images of a 20 mm rebar embedded within a sample containing 10 mm aggregate.