Evaluation of the surface crack depth in concrete by impact-echo procedures (SIBIE)

The impact-echo method is available for estimating the surface-crack depths. This method is based on monitoring wave motions resulting from a short-duration mechanical impact. Surface displacements are detected by identifying peak frequencies in the frequency spectra. However, the frequency spectra cannot always be interpreted successfully as many peaks are often observed in the spectra. Thus, an imaging procedure to the impact-echo data which is knows as SIBIE procedure is developed. After confirming an applicability of the SIBIE procedure to estimate the depths of open surface cracks, it is clarified that the effect of water filled in the crack is inconsequent. Thus, even though the cracks are filled with water, the depths can be estimated with reasonable accuracy by SIBIE. In addition, the case where the surface cracks are repaired improperly and the void exists around the crack-tip is studied. In all the cases, surface-crack depths could be visually identified by the SIBIE procedure.