A new methodology for concrete resistivity assessment using the instantaneous polarization response of its metal reinforcement framework

Abstract

A new methodology is developed to assess concrete cover resistivity using the instantaneous response of the polarization of a metal rebar (galvanostatic pulse method). The instantaneous ohmic drop is linked only with the concrete resistance, which depends on the concrete cover and resistivity, and rebar diameter. A numerical model was developed in Comsol Multiphysics® in order to create a graph linking concrete resistivity to concrete resistance for concrete cover ranging between 1 and 160 mm. This graph and the measured ohmic drop can be used to determine concrete resistivity for any rebar diameter/concrete cover configuration. The theory developed numerically was then confirmed using an experimental setup with controlled water resistivity. The theory is then generalized for counter electrode (CE) diameter ranging from 20 to 70 mm. Finally, the study reveals that the graph developed for a single rebar can be used for any rebar framework density.