Title:
Polarization Period, Current Density, and the Cathodic Protection Criteria
Author(s):
Mohammad Golam Ali and Rasheeduzzafar
Publication:
Materials Journal
Volume:
89
Issue:
3
Appears on pages(s):
247-251
Keywords:
cathodic protection; current density; reinforced concrete; Materials Research
DOI:
10.14359/2573
Date:
5/1/1992
Abstract:
The - 850-mV CSE "instant off" potential and the 100-mV decay potential cathodic protection criteria applicable to reinforced concrete structures have been studied with emphasis on their dependence on polarization period and current density. Four constant current densities of 1, 3, 20, and 60 ma/ftý of the steel surface area were maintained on reinforcing steel embedded in mortar specimens, and the "instant off" potentials, as well as the decay potentials, were recorded for different polarization periods and current densities. The "instant off" potential value was observed to increase with polarization time and current density. The same trend was noted in the case of 4-hr decay potential. It was also found that a current density of 1 ma/ftý of the steel surface area is inadequate to satisfy either the "instant off" potential or the decay potential criterion, whereas a current density of 3 ma/ftý is more than sufficient to satisfy the decay potential criterion, while inadequate in satisfying the "instant off" criterion. Complete depolarization in a 4-hr period is possible with 1, 3, 20, and 60 ma/ftý CP current densities. The aggregate type has no noticeable effect on the "instant off" potential and the decay potential values.