Microwave dielectric properties inspection of fiber-reinforced civil structures

A non-destructive technique based on microwave frequency dispersion (or equivalently time-delay) measurements has been proved to perform an analysis of the density and spatial fiber distribution of the fiber-reinforced civil structures. This technique has a sensibility and dynamic range compatible with the actual needs of the civil structure measurements. In the range from 500 MHz to 3 GHz a kind of mathematical rule can be extracted in order to relate the steel fiber density in the material with the equivalent permittivity.