New concept of measurement apparatus for the in situ electrical resistivity of concrete structures

This paper presents the prototype of an apparatus (AMSR) in the 2.5 accuracy class, which operates at 500 Hz, for measuring the in situ resistivity of concrete in the range 5...100 Ωm that is immune to errors due to the polarization phenomena at the interface probe/concrete sample. The direct problem of the electrical resistivity tomography, ERT, is then solved for DC and AC electric fields a sample-specific geometrical factor that provides for a convenient mean of calibrating the AMSR output against different standard concrete samples is defined. The direct problem is an important stage in solving for the inverse problem of ERT that consists in finding the electrical resistivity of the sample out of boundary (measured) data, and it makes the object of future research.