Determination of the Vertical Crack Depth in Concrete by the Ultrasonic Time of Flight

초음파 도달시간에 의한 콘크리트에서의 수직 균열의 깊이 측정에 관한 연구

Depths of the vertical cracks in the concrete were determined by the time of flight of the ultrasonic waves. The ultrasonic waves are diffracted at the crack tip, and the arrival time of ultrasonic waves are dependent on the crack depth and speration distance between transmitting and receiving ultrasonic transducers. The vertical cracks with 0.2-2mm width and 10-100mm depth were examined by multi-layered ultrasonic transducers. It was found that the time of flight of ultrasonic waves were proportional to the depth of vertical cracks. The depth of vertical cracks in the range of 20-100mm depth could be determined by the transient time of the diffracted ultrasonic waves