Acoustic Tomography for Qualitative Nondestructive Evaluation (QNDE) of Structural Concrete using a New Ultrasonic Scanner Source

Abstract

Civil engineers have used Nondestructive Testing and Evaluation (NDT&E) methods based on Ultrasonic Pulse Velocity (UPV) measurements as far back as the 1940’s to evaluate the condition of new construction and monitor the integrity of the existing infrastructure. A major emphasis in concrete NDT is the evaluation of concrete integrity and the detection of defects such as voids, honeycomb, cracking, and delamination in concrete. The conventional UPV tests (ASTM Standard C597-83) may indicate the presence of a flaw, but are limited in determining the depth (but not the lateral definition) of the flaw. The commercially available UPV systems all use point-by-point measurement approaches that are too slow to economically gather enough information to create images of internal conditions for large concrete areas.