Development of a New Sacrificial Cathodic Protection System for Steel Embedded inConcrete

摘要

This is the interim report for a study to evaluate the use of sacrificialcathodic protection for reinforced and prestressed concrete bridge members. Cathodic protection (CP) using impressed current is an accepted and common method used to provide corrosion protection to steel in concrete. Sacrificial cathodic protection, however, is relatively easy to apply, does not require that the anode be electrically isolated from the steel, and does not require an external power supply. Attempts to apply sacrificial anode CP to bridge structures have met with limited success because conventional sacrificial anode alloys operate at a low fixed potential and the conductivity of concrete often does not permit satisfactory current output. The Florida Department of Transportation has applied arc-sprayed zinc to several bridges in the marine environment. The study examined the performance of existing sacrificial alloys in different environments for sacrificial CP, and developed new sacrificial alloys for protecting steel in concrete. The study consisted of both laboratory and field tasks.