The metallic fibers interact with the magnetic field generated in the coil and an impedance variation is recorded. Based on this variation it is possible to determine the content and orientation of the fibers.
The test can be carried out on cubic specimens with dimensions of 150x150x150 mm and cylindrical specimens of Ø150×150 mm, although it allows the analysis of smaller specimens. In addition, it can be used for the analysis of specimens manufactured in a mold and samples extracted from existing structures.
An initial calibration is required to establish the correlation between the inductance values and the amount of metal fiber. This calibration is unique for the type of fiber and independent of the dosage of the concrete.
To determine the content and orientation of the fibers in a test piece, only three measurements are necessary in the three main directions X, Y, Z of the test pieces.