On-site measurement of delamination and surface crack in concrete structure by visualized NDT

On-site measurement in concrete piers of a highway structure was conducted by visualized non-destructive testing (NDT). First, the radar technique was applied to identify delaminated areas between pre-stressed concrete (PC) panels covered and original concrete piers. By applying the impact-echo method, Stack Imaging of spectral amplitudes Based on Impact-Echo (SIBIE) procedure is developed as an imaging technique, which can visually display a cross-sectional view based on the impact-echo data. In order to identify voids in delaminated areas and depths of surface cracks, then the impact-echo tests were conducted. From these results, a superior applicability of the SIBIE procedure to on-site measurement is demonstrated in existing concrete structures.