The radar method is an electromagnetic wave process. Radiated impulses are spread into the object under examination by means of a transmission antenna. Should they meet layer interfaces at which the electrical characteristics change then they are reflected and picked up by a receiving antenna. Such layer interfaces are located for example at the intersection of the concrete with the reinforcing steels or the boundary of asphalt to concrete.
Radar measurement is deployed on complex, multi-layered reinforcement or large concrete coverage. Even the interface between hardcore or asphalt and concrete, on bridges for example, can be reliably recognised using the radar process. Prior to carrying out core sampling, radar measurement is likewise used to locate ducts or pre-stressing elements.
During the survey the radar measuring unit, equipped with transmission and receiving antennae, is moved continuously along the surface of the object being examined. At the same time it takes radar measurements at intervals of a few millimetres. The measured results are illustrated graphically based on a cross-section or layer pattern.