Development non-contact, non-destructive evaluation for concrete structures by using shock wave and study of its automation

We developed a basic technology of non-contact, non-destructive inspection method of a concrete structure. It is a current inspection approach that an operator beats surface of a wall with a hammer and hears the sound with his ears, and judges the presence of the defect. The purposes of this study are the improvement of reliability and the curtailment of expenses by the automation of evaluation. The proposed method of this study is that the impact by hammer is replaced with shock wave and the safety check by operator's ears is replaced with the laser measurement. We did a simulation using a finite element method and succeeded detection of a defect of 25 mm diameter and in 200 mm depth. The method of this study is a technology to enable that we inspect concrete structures by non-contact, non-destructive test automatically.