Abstract
The ultrasonic method is expected as a quantitative evaluation method of the damage for concrete structures. However conventional ultrasonic measurement systems for steel structures are difficult to apply for industrial concrete structures due to the large noise which considered as the ultrasonic scattering of aggregate in mortars. Thus applied frequency is lowered to 20 kHz for example and only the first traveling echo of penetration layout is used until now. However ultrasonic measurement is still difficult and have not recognized as a common evaluation method for concrete structure. In this research, after the simulation of the three dimensional concrete model by large-scale FEM, we focused on the large dispersion of the transmitted echo due to the velocity difference between aggregate and mortal. Then the super-broad band ultrasonic measurement system using step function pulser for the frequency of 500 kHz or less was applied for the penetration and reflective measurement of the concrete specimen with a thickness of 200 mm Furthermore, waveform treatment procedures for improving the S/N ratio were applied as a basic research of the ultrasonic evaluation for a industrial concrete structure.
