Characterization of Microcracking in Polymer Concrete Using Multiple Scattered Waves Under Steady-State Vibration Conditions

ABSTRACT

This work presents the development of an ultrasonic method based on the use of multiple-scattered waves to detect and image microcracks in polymer concrete samples under steady-state bending vibrations. The sensitivity of the multiple-scattered waves to microcracks revealed to be dependent on the plane in which bending vibrations were excited. In order to understand the origin of such a sensitivity, acoustic emission measurements were performed under the same vibration conditions to verify the existence of a structural anisotropy related to microcrack distribution. Results revealed that, depending on the considered plane, acoustic emission signatures are very different and therefore can be used to understand the involved mechanisms and to identify the vibration planes that offer the optimal imaging conditions.

KEYWORDS:

• Acoustic emission
• air-coupled ultrasound imaging
• damage anisotropy
• polymer concrete
• ultrasonic multiple scattering