Investigating concrete structures by 3D Radar imaging and imaging using mechanical impact

Imaging of various types of anomalies at limited depths can be achieved even behind a layer of reinforcement. Linking radar data to data from acoustic methods is made possible in the scanning system. This paper presents an equipment developed at Lund Technical University with the financial support from owners of bridges and hydro power stations, and which has been used for laboratory as well as field experiments: a mechanical scanner moves an antenna or acoustic probe from one measurement point to the next thus allowing measurements to be made in a grid over the surface of the structure; the measurement equipment is positioned in the in line direction of a scanner beam with one servo motor, and in the transverse or cross line direction the entire beam is moved on wheels controlled by a second servo motor. It shows that different types of objects appear differently depending on the measurement method and thus a better understanding of types of defects can be achieved by combinations of results. The equipment has not been tested at greater depths but it is likely that information will be picked up. The size and shape of objects will however be more distorted thus making further processing of data necessary in order to improve the sensitivity of sizing defects