Imaging concrete cracks using Nonlinear Coda Wave Interferometry (INCWI)

Crack imaging in highly heterogeneous materials, such as concrete, plays a great role structural health monitoring and non-destructive evaluation testing. Numerous works have shown that Nonlinear Coda Wave Interferometry is robust tool to assess the overall level of nonlinearity caused by micro or macrocracks media. This work presents novel qualitative method for Imaging using NCWI (INCWI) based on combination (NCWI) spatial averaging method. INCWI used herein locate cracks generated concrete beam subject three-point bending. Measurements are performed after each loading level, both pre-peak post-peak phases, once has been unloaded. The algorithm described applied stage damage. In phase, crack size varies from 10 cm 15 length 25 μm 200 width. Also, results compared with acoustic emission measurements microscopic observations.