Laboratory Study on Electrochemical Repair for Reinforced Concrete Exposed to Chloride ions Environment

Due to the “Ring-Anode” effect, reinforced concrete structures will shortly appear to have more serious corrosion deterioration after repairing by conventional rehabilitation methods in a chloride ion environment. Electrochemical repair methods have proved to be an effective and reliable technique for the protection of reinforced concrete structures, especially sacrificial anode cathodic protection (SACP) systems. In the study, active mortars were developed by adding polypropylene (PP) fiber and humectants. Adding PP fiber is intended to control the early shrinkage cracking of the active mortar, and increase the porosity of the active mortar for corrosion products to migrate easily. Using humectants intends to improve resistivity of the active mortar surrounding the anode and performance of the embedded sacrificial anode. The physical and electrochemistry performances of the active mortar were tested compared with the ordinary mortar. In the laboratory, a simulated chloride ions environment was used to evaluate the active mortar with a zinc mesh sacrificial anode for repairing and protecting the reinforcing bar from corrosion in a reinforced concrete column. The tested concrete column was submerged in the salt water and exposed to the air laboratory alternately. According to the criterion of cathodic protection (CP) for reinforced concrete, the reinforcing bars were protected effectively.