The Experimental Measurement on the Throwing Power of Sacrificial Anode Cathodic Protection for Concrete Piles in Natural Sea Water

Abstract

This paper represents the experimental studies on the throwing power of sacrificial anode cathodic protection system applied to reinforced concrete piles in salt water condition by means of zinc anodes. Many previous studies show the effectiveness of sacrificial anode cathodic protection system, however, the major problem of sacrificial anode cathodic protection system is limited a distance to the point reaching protection current from the anode in high resistivity environments such as concrete, etc. In case of concrete pile in sea water condition, it should be combined submerged zone, tidal zone, splash zone, and atmospheric zone. In this study, the cathodic protection current by zinc sacrificial anodes was limited to scores of centimeters above the water line with tidal, depending on the concrete resistivity. Experimental tests were carried out on pile type reinforced concrete specimens with the change of water level. The test factors were corrosion and protection potential, current, and 4 hour depolarization potential. As a result of tests, cathodic protection current by zinc sacrificial anode was influenced up to about 10cm above the water line, and high resistivity areas such as atmospheric zone could not be protected with this system.