Cathodic Protection of Reinforced Concrete Seawater Structures in Petrochemical Plants

摘要

The long-term performance of both case histories have shown that CP is an effective and durable method of controlling corrosion of steel in chloridecontaminated concrete and provides a longer-term solution than conventional structural or patch repairs. It appears that a steel CD of 15 mA/m~2 is sufficient to provide adequate protection in reinforced concrete seawater structures. Initially, the current demand may be high in some highly corroded or chloride-contaminated areas, but after 2 or 3 years the required current level is significantly reduced to between 8 and 12 mA/m~2 of the steel area. For thick concrete slabs or walls (>200 mm thick), anodes should be placed on both sides to achieve better current distribution and adequate protection. Otherwise, the afforded protection level could be insufficient in controlling corrosion of the reinforcing steel that would lead to concrete cracking.