Evaluation of characteristic of pulsed laser irradiation on concrete using a QCW laser system

Nguyen, P. L.; Daido, Hiroyuki; Matsunaga, Yukihiro; Terada, Takaya; Yamada, Tomonori; Kawachi, Tetsuya

Laser irradiation techniques for removing degraded parts of concrete structure such as tunnel concrete of railways safely and efficiently is an urgent task, since the significant defects in wall concrete have been detected in the JR West tunnels, Japan. Pulsed laser processing of material is an important part of the laser technical application, which include laser drilling, welding, cutting, etc. In this work, we used the QCW (Quasi continuous wave) fiber laser system with advantages of compact dimensions and high peak power. An understanding of mechanisms of ejected molten material and characteristic of hole drilled in laser drilling concrete is necessary to enhance the performance for pulsed laser irradiation on concrete. This basic study of pulsed laser irradiation provides useful information to control and enhance the performance for laser irradiation on concrete.