Title: Errors in the On-site Measurements of Rebar Corrosion Rates Arising From Signal Un Confinement

Author(s): S. Feliu, J. A. Gonzalez, and C. Andrade

Publication: Symposium Paper

Volume: 151

Issue:

Appears on pages(s): 183-196

Keywords: corrosion; electric measuring instruments; measurement; polarization; reinforced concretes; reinforcing steels; General

DOI: 10.14359/4383

Date: 7/1/1994

Abstract:
On-site monitoring of the rate of corrosion of reinforcements is a priority task. There are various available devices for measuring I corr. Most of them entail a prior measurement of the {DELTA}E/{DELTA}I, which defines the polarization resistance (R p). However, direct estimations of R p from the {DELTA}E/{DELTA}I ratio are usually unfeasible with large structures because they provide an apparent polarization resistance (R p app) that differs to a greater or lesser extent from the true R p value depending on the experimental conditions. This paper analyzes the influence of some experimental factors (that is, the use of unconfined or guard ring-confined electric signals, the CE size, and the presence of active and passive areas in reinforcements) on the R p app accuracy of the I corr values derived from it. The more correct I corr values can be obtained by sensorized confinement of the electric signal applied with the aid of a guard ring and supplementary reference electrodes for monitoring the electric field confinement.