Inversion Based Retrieval of the Profile of the Degree of Moisture Saturation in Concrete Using Electrical Impedance Measurements

Moisture content has implications on the durability and service life of a concrete structure. Measurement of the moisture content is usually performed via non-invasive electrical techniques. In this paper, the electrical response of hardened concrete is acquired and correlated to the Degree of Saturation (DoS) of the material. The pulsed electrical excitation is imposed on the sample and the output is recorded at various electrode locations along the sample length. Using a one dimensional circuit model and a Gaussian and Inverse Multiquadric Radial Basis Function (RBF) based inversion scheme, the cumulative and spatial distribution of the real and imaginary parts of the impedance are re-constructed along the length of the sample. An excellent fit with the experimental data is observed and an empirical relationship is proposed between the DoS and the absolute impedance, which would facilitate the estimation of the DoS profile in samples with homogeneous and non-homogeneous moisture distribution.

Automated summary

Moisture content significantly affects the durability and service life of concrete structures. Non-invasive electrical techniques are commonly used to measure moisture content and correlate electrical response to the Degree of Saturation (DoS) of the material. A study successfully reconstructed the impedance distribution along the length of samples and proposed an empirical relationship between DoS and impedance for estimating moisture profiles in samples with different moisture distributions.