DETERMINATION OF THE POLARIZATION RESISTANCE OF REBAR IN REINFORCED-CONCRETE

The problem of determining the polarization resistance of rebar in reinforced concrete is addressed by modeling the electrical properties of the rebar/concrete system as a bifurcated transmission line. The polarization resistance, concrete resistance, and the interfacial capacitance are obtained by fitting the model to experimental impedance data using nonlinear regression analysis. Although the efficiency of this procedure depends on the quality of the initial estimates for the model variables, we show that the final values obtained are independent of the initial values used in the analysis. Finally, we explore the distribution of the current along the rebar as a function of the polarization resistance, concrete resistance per unit length of the rebar, and the frequency of the applied alternating voltage perturbation. We show that the current distribution becomes a particular problem at low frequencies when the concrete resistance is low and/or the polarization resistance is high.