Project Overview
The Punaluu Stream Bridge is situated only steps away from the Pacific Ocean, exposing it to harsh marine conditions. Strong trade winds, chloride-laden rainfall, and volcanic emissions combine to create a highly corrosive environment that threatens the durability of the structure. A corrosion protection solution was required to ensure long-term performance of the bridge.
Problem
Punaluu Stream Bridge is located close to the ocean and exposed to continuous trade winds averaging 17–28 mph, reaching 40 mph in winter. The environment is heavily contaminated with chlorides and sulfuric dioxide from volcanic activity. Inland water reports show rainfall with a pH of 4.5, meaning rainwater combines with chlorides to create a highly corrosive atmosphere. These conditions threaten both post-tension cable systems and surface-exposed concrete, necessitating a robust corrosion mitigation approach.
Application
MCI®-309 Powder
Injected into the post-tension chambers immediately after the post-tension cables were placed.
• Does not need to be removed prior to grouting
• Readily absorbed by the grout once injected
MCI®-2005 NS
Added as an admixture into the new concrete placed on the bridge to protect reinforcing steel from chloride-induced corrosion.
Conclusion
Cortec’s MCI®-309 and MCI®-2005 NS provided strong corrosion protection in an exceptionally aggressive environment. MCI®-309 was selected for its ability to safeguard post-tension systems without removal prior to grouting, while MCI®-2005 NS protected steel reinforcement in new concrete. Together, these materials significantly extended the expected service life of the structure.