NDE of Tendon Ducts in Concrete using 3D-SAFT

Prestressed or post-tensioned concrete structures are vulnerable to hazardous corrosion, if the tendon ducts are not fully injected with grout. Also compaction faults reduce the concrete strength. Advanced ultrasonic testing techniques and data analysis have been utilized to evaluate ducts in concrete members nondestructively. A laser Doppler vibrometer is used as an ultrasonic receiver to automatically collect the data. With this method ducts could be investigated which are not accessible by other methods as radiography or impact-echo. Encouraging results on different specimens are presented.