Title:
Measurement of Reinforcement Corrosion Rate Using Transient Galvanostatic Pulse Method
Author(s):
Hyoung-seok So and Stephen Geoffrey Millard
Publication:
Materials Journal
Volume:
105
Issue:
4
Appears on pages(s):
350-357
Keywords:
corrosion; galvanostatic pulse; impedance; linear polarization; reinforcement; transient response
DOI:
10.14359/19896
Date:
7/1/2008
Abstract:
A galvanostatic pulse transient response technique was investigated to evaluate the corrosion rate of steel reinforcement in concrete structures. Galvanostatic pulse transient measurements were conducted on a number of short sections of steel bar embedded in concrete. The duration of an applied galvanostatic pulse was varied between 30 to 180 seconds. The resulting transient potential response was investigated using a typical sampling rate of 1 kHz. The electrochemical potential transient response was analyzed to obtain separate equivalent electronic components, comprising a series of resistances and capacitances, whose values are dependent on the corrosion condition of the reinforcing steel. The corrosion rate was evaluated from a summation of the separate resistive components and compared with a corrosion rate determined from taking a conventional linear polarization resistance (LPR) measurement on the same specimens. The results obtained show that the galvanostatic pulse transient technique enables the separate components of the polarization resistance to be resolved, which offers significant advantages over either the potentiostatic or galvanostatic LPR method and provides a more conservative evaluation of the ongoing rate of corrosion.