This paper presents the results of the effects of anodes for impressed current cathodic protection (ICCP) system on reinforced concrete. Experimental tests were carried out on reinforced concrete specimens with 3 different kinds of commercial anodes that are used for ICCP in order for comparative study. Results have shown that the type of anodes is irrelevant to the effectiveness of cathodic protection. CP current similarly flowed to the anodes regardless of anode types in seawater condition. In addition, current was much higher in seawater condition than freshwater and air condition. The results show that titanium rod anode was slightly more effective in fresh water, and titanium mesh anode showed a better performance in atmospheric condition. The potential drop caused by concrete resistance in atmospheric condition should be considered at depolarization potential measurement.

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.

This study represents the result of hybrid cathodic protection (Hybrid CP) system application. Hybrid CP, which is the combination between sacrificial anode cathodic protection (SACP) system and impressed current cathodic protection (ICCP) system, can be optimum way to protect corrosion, especially in concrete columns. In this study, sections below a water line, i.e. submerged and tidal zones, were cathodically protected by means of SACP. In addition, ICCP was applied to the upper areas of water line, i.e. splash and atmospheric zones. Water level was changed to verify the effectiveness of hybrid CP system. The test factors were natural, CP, and 4-hour depolarization potential.

This study represents the lifetime prediction of fire extinguishing pipeline within the framework of corrosion. In this case, carbon steel was used as a material for fire extinguishing pipeline. Total 24 samples were selected, which was determined by specimens position, pipeline diameter, and pipeline thickness. Used test methods were view inspection and extreme value statistics using the Gumbel distribution. Especially, by utilizing extreme value statistics, the prediction of remaining life was confirmed as a specific numerical value. As a result of view inspection, pitting corrosion was occurred in several samples. In addition, extreme value statistics demonstrates that several pipelines were very sensitive at pitting corrosion. However, the pitting corrosion of all pipelines was not critical; thus, all pipelines dont need to be changed for a safety regulation.

In the present study, corrosion and cathodic protection (CP) characteristics of concrete piles exposed to marine environments such as marine bridge columns or pier structures were evaluated under simulated conditions. The accelerated environmental tests were carried out at an elevated temperature (40°C) and a high chloride concentration (15%). The protection potential of CP systems with Zn-mesh sacrificial anodes applied to piles was inversely proportional to the water content in the concrete. When the CP system was applied after corrosion initiation and propagation (CProt), the protection current density was higher than when the CP system was applied at the beginning of structural construction (CPrev). However, the four-hour depolarization potential was higher in the latter case than in the former. In addition, it was found that even though the current density of the CPrev system was relatively lower than that of the CProt system, the CPrev system was also able to prevent corrosion. Consequently, both CProt and CPrev systems are very effective at preserving reinforced concrete structures, especially in marine environments.