Ultrasonic NDE of concrete

In this contribution an overview of ultrasonic non-destructive evaluation (NDE) of concrete is given. The intention is to provide insight into the specific features of concrete testing, and to build a picture of this rapidly developing field by presenting examples of research results and applications. After introducing concrete as a construction material and inhomogeneous propagation medium, common inspection tasks at civil structures are identified. Characteristics of ultrasonic wave propagation in concrete are explained together with measurement and modeling methods. A short presentation of measurement systems precedes the description of research and applications examples. This subjective selection comprises measurement and signal processing techniques including imaging. The list encompasses well-tried methods as well as topics of current research. Finally, the current state of development is discussed in view of demanded testing objectives.