Accelerated Laboratory Assessment of Discrete Sacrificial Anodes for Rehabilitation of Salt-Contaminated Reinforced Concrete

Abstract

For patch repairs of chloride contaminated RC structures, the use of discrete sacrificial anodes (DSAs) is indispensable. Without DSAs embedded, due to the ring effect, the failure of the RC around the patch area is accelerated. DSAs are increasingly being used, but few studies have evaluated the effectiveness of different DSAs and effects of the surrounding environment on the performance of different DSAs. This study employed four electrical parameters and electrochemical impedance spectroscopy (EIS) to evaluate three types of DSAs embedded in chloride-contaminated concrete through wet–dry and freeze–thaw cycles. The corrosion of the reinforcements is a stochastic process and the bound chloride ions play an important role in determining the corrosion state of the reinforcement. Most of the DSAs provided effective cathodic protection, but the effectiveness of DSAs could be influenced by the corrosion state of the reinforcement. The wet–dry and freeze–thaw cycles had significant influence on the performance of two types of the DSAs. Current DSA designs do not fully utilize the embedded Zn alloy.