ABSTRACT
In this paper, we proposed a non-destructive evaluation method for judging the condition of the PC duct whether it is filled with grout material. If water stays inside the duct, it causes severe damage in terms of corrosion in steel strands and needs to be detected. Still, there is a risk that it might be overlooked by elastic wave methods such as ultrasonic waves in the duct condition of “grout-unfilled with water”. This problem was solved by filtering by parasitic discrete wavelet transform and focusing on the signal level of the reflected waves in each duct condition.
