TREATMENT OF REINFORCING BARS DURING CONSTRUCTION OF CONCRETE STRUCTURES TO PREVENT CORROSION

THE CORROSION OF STEEL REINFORCING BARS (REBAR) IN CONCRETE STRUCTURES IS A PROBLEM WITH MULTI-MILLION DOLLAR IMPACT IN BOTH THE PRIVATE AND PUBLIC SECTORS. CHLORIDE INTRUSION FROM NATURAL (SEAWATER OR MARINE ENVIRONMENTS) OR MAN-MADE (DEICING SALTS) SOURCES CONTRIBUTES TO THE BREAKDOWN OF THE PROTECTIVE IRON OXIDE FILM ON THE STEEL. THE SUBSEQUENT REACTIONS CREATE VOLUMINOUS CORROSION PRODUCTS, CAUSING CRACKING AND SPALLING OF THE OVERLYING CONCRETE AND REDUCING THE EFFECTIVE STRENGTH OF THE ENTIRE STRUCTURE. IN THE PROPOSED PROGRAM, AN ELECTROCHEMICAL METHOD FOR ENHANCING THE CORROSION RESISTANCE OF THE REBAR DURING THE INITIAL CONCRETE CURING PERIOD WILL BE INVESTIGATED. THE INNOVATIVE METHOD IS IN SITU PASSIVATION OF THE REBAR SURFACE BY APPLICATION OF AN ANODIC POTENTIAL. THIS TREATMENT WILL ENHANCE THE PROTECTIVE IRON OXIDE FILM ON THEREBAR BY MAKING IT THICKER AND MORE UNIFORM. THE EFFECTIVENESS OF THIS TREATMENT IN ENHANCING THE CORROSION RESISTANCE OF REBAR WILL BE EVALUATED IN SIMULATED ENVIRONMENTS AND IN MORTAR-REBAR SAMPLES.