The ground penetrating radar (GPR) method uses electromagnetic energy, emitted at regular intervals by an antenna to map subsurface features and discrete objects.
The electromagnetic pulses are reflected where changes in electrical properties (e.g. dielectric constants) occur. In the case of collecting GPR data on concrete structures, these reflections may occur due to the presence of rebar, cracking, voids, or the far side of the structure in question.
Non-Destructive Testing: Ground Penetrating Radar