Ageing concrete structures have been significantly increasing. To sustain those, understanding the damages and decision the time and method of repairing is a crucial issue. Non-destructive testing (NDT) appears to contribute to this paramount issue, since it includes a variety of testing methods corresponding to the measurement scale. NDT also provides momentous information on the effects of repairing when the test is repeated after the repair work. In this study, seismic tomography, one of NDT methods, was applied for the damage quantification of full-scale concrete structures. The test was conducted both before and after repairing. The distributions of velocity led to a conclusion that the velocity variations represented well the effects of repairing.
