Article ID: 24-00429
This study presents a novel remote impact echo testing method utilizing pulsed water jets for non-destructive inspection of concrete structures. The method provides advantages over traditional impact methods by enabling efficient long-distance inspections while minimizing water consumption. The pulsed water jets also exhibit improved resistance to wind interference and generate a broader range of excitation frequencies, enhancing defect detection accuracy. To validate the method, experiments were conducted using concrete specimens embedded with artificial cavities to simulate structural defects. The system employed a 4 mm diameter nozzle operating at 1 MPa, generating high-speed water pulses with a velocity of approximately 40 m/s. The resulting impact-induced acoustic signals were recorded using a gun microphone, and frequency spectrograms were analyzed to identify defect-related resonant frequencies. The tests confirmed that defects at a depth of 20 mm and diameter of 300 mm could be successfully detected from a distance of 3 m. Additionally, spatial mapping of impact intensity was performed, revealing that regularly spaced impacts improve defect localization accuracy. The results demonstrate that the pulsed water jet method is a viable and effective alternative for remote defect detection in concrete structures, particularly in areas where direct access is restricted.
