Civil Engineering Reference
In-Depth Information
'artificial intelligence' has been used to help with interpretation of complex
radar traces.
Some modern equipment has the ability to present data as 2D or even
3D plots showing an indication of the detected features, which are easier to
interpret than the parabolic-type reflections normally encountered in radar
plots.
Radar reflects most strongly off metallic objects or from the interface
between two materials with widely differing permittivities. An air-filled void
in dry concrete, which does not differ very strongly in permittivity from the
concrete itself, can therefore be difficult to detect, especially if the void is
small. The same void filled with water, however, would be much more easily
detected.
Water strongly attenuates a radar signal and using a 1 GHz antenna,
typical practical penetrations of around 500 mm have been achieved for
dry concrete, and 300 mm for water-saturated concrete. If the water is
contaminated with salt, penetration is likely to be smaller still.
