Assessment of Concrete Beams with Irregular Defects Using Surface Waves
Previously individual surface-breaking cracks in concrete were examined successfully by monitoring the changes in velocity and attenuation of surface waves. However, an overall assessment m ethodology for the structural elements with irregular defects has not been in the scope. The motivation of th is study is to extract reliable diagnosis features from the surface waves in order to evaluate the condition of concrete elements with irregularly distributed defects . Therefore, six laboratory scale concrete beams with different defect volum es are produced by mixing Styrofoam pellets in the fresh concrete mix. The ultrasonic tests are conducting by imp lementing a multi-channel testing configuration and the recorded surface waves are analyzed by mploying techniques such as wavelet and 2D Fourier transforms to determine the attenuation and dispersion respectively . Despite the complex structure of the defect patterns, promising results are obtained from attenuation and dispersion ba ed features, as 100% change in both is observed for 30% defect volume.