Solvent-based acrylic carbon paint anodes were installed on the north approach spans of the Yaquina Bay Bridge (Newport OR) in 1985 and performed well after 15 years. Anodes were inexpensive and repairs easy. Depolarization potentials are consistently above 100 with long-term current densities around 2 mA/m 2. Bond strength remains adequate.
The phenomenon of a potential-dependent chloride threshold (PDT) along with the corrosion macrocell coupling between active and passive steel assembly components allows to combine a corrosion initiation-propagation model to forecast the durability of reinforced concrete structures in marine service.
The Houston Ship Channel is a modern engineering feat. Brackish water. Chloride induced corrosion. Subsidence. Change in water levels and exposure conditions. These issues are explored in this paper reviewing methodologies and results of service life modeling from a recent multi-structure assessment by the authors.
For reinforced concrete (RC) structures that are in drier locations but still need of cathodic protection (CP), impressed current cathodic protection (ICCP) systems are preferred. In this study, the performance of activated zinc anodes installed on dry or high resistance concrete on Florida Bridges was evaluated.
Marine environments can be very aggressive and present significant challenges in maintaining key infrastructure from the effects of corrosion. In Florida, thousands of bridges are in coastal areas and are continually, or periodically exposed to saltwater conditions. A clear majority of these bridges were constructed using steel reinforced concrete and are supported by precast pilings situated in saltwater, so for this reason, cathodic protection is a necessary strategy for controlling the effects of saltwater induced corrosion.
Toward the early 1980s, the Florida Department of Transportation (FDOT) began the evaluation of different approaches to control saltwater induced corrosion. Some of these included the use of integral pile jackets, specialty materials for concrete repairs, surface applied coatings and other innovative approaches utilizing galvanic anode technology. One such system was jointly developed with industry partners and sponsored by the Federal Highway Administration (FHWA) using integral pile jackets lined with expanded zinc mesh anodes to apply cathodic protection. This innovative approach provides for the problem of concrete repair while at the same time stopping the on-going process of corrosion both combined in one application. Both laboratory and field trials validated the benefits to this approach and confirmed that the system can mitigate corrosion and extend the useful service life of pilings by more than 20 years.