CONVENTIONAL MONITORING AND FUNDAMENTAL ELECTROCHEMICAL METHODS FOR ESTABLISHING THE EFFICIENCY OF AN ALTERNATIVE CATHODIC PROTECTION FOR REINFORCED CONCRETE

摘要

The applicability and efficiency of an alternative for impressed current cathodic protection (CP) for reinforced concrete, based on pulse technology, was investigated. The technique, denoted as pulse cathodic protection (pCP), was evaluated on the basis of a comparative analysis to reference (non-corroding), corroding and conventional CP conditions in terms of monitoring the corrosion behavior and defining the electrochemical parameters for the embedded steel with time of corrosion and protection. The hereby reported results are for the total duration of the experiment i.e. 460 days of conditioning. Protection was applied after corrosion was initiated (using corrosion medium of 5% NaCl), at different time intervals (here reported are starting points 60 and 150 days of age). Both CP regimes used current density of 5 or 20 mA/m~2 steel surface. The pulse CP was achieved by applying a pulse shaped block current (square wave) with the current itself being the feedback control signal, using 12.5% to 50% duty cycle at 100 Hz to 1KHz frequency. In equal environmental conditions the pulse CP was found to perform as effectively as the conventional CP with regard to electrochemical behavior of the steel reinforcement.