METHOD FOR MEASURING SURFACE OPENING CRACK DEPTH OF CONCRETE BY ULTRASONIC WAVE

摘要

PURPOSE:To measure the depth of a crack easily in a real time with high accuracy, by inputting a low frequency surface wave to concrete from the transmitting probe among the transmitting and receiving probes brought into contact with the surface of concrete in opposed relationship across the crack. CONSTITUTION:A transmitting probe 12 and a receiving probe 13 are brought into contact with the surface 11a of concrete 11 to be measured in opposed relation to a crack 14 and a low frequency surface wave is allowed to be incident to the concrete 11 from the contact surface of the probe 12. The incident surface wave propagates to the leading end of the depth of the crack 14 and the transversal wave of the component parallel to the surface of the concrete 11 converted in a mode at said leading end is received by the probe 13 and the propagation time received through the routes of the surface wave and transversal wave is measured as an evaluation index. By this method, the depth of the open crack 14 on the surface 11a of the concrete 11 can be easily measured with good accuracy in a real time.