Reinforced concrete forms the backbone of our modern world. Yet, the very element that strengthens it, steel reinforcement, also introduces the risk of corrosion. This silent adversary leads to concrete spalling, delamination, and ultimately, structural failure. At Vector Corrosion Technologies, we understand the critical importance of safeguarding these vital assets. Let's delve into the advanced strategies that can combat concrete corrosion and extend the lifespan of your infrastructure.

Understanding the Enemy: What Fuels Concrete Corrosion?

Corrosion isn't a singular event; it's a complex process that can be driven by multiple factors:

• Aging Infrastructure: As structures age, they become more susceptible to moisture, chemical, and temperature fluctuations. Older structures are at greater risk of carbonation induced corrosion.
• Chloride Ingress: Water and chloride ions (from seawater or de-icing salts) penetrate concrete, reaching the rebar and initiating rust. This expansion creates internal pressure, leading to cracking and structural damage. This process is accelerated in freeze-thaw climates.
  • Marine Environments: Coastal areas face heightened risk due to saltwater and high humidity, which aggressively attack concrete structures.
  • Corrosive Soils and Capillary Action of Chlorides: Certain soil types contain high concentrations of sulfates and chlorides, which can aggressively attack concrete.  Capillary action draws these corrosive substances upwards, even from below the concrete, leading to deterioration of foundations and substructures.
• Incipient Anode Formation (Halo Effect): Corrosion around repaired concrete sections occurs due to abrupt electrochemical imbalances between old and new concrete. Proper repair techniques and corrosion mitigation are crucial to prevent this.

Get a deeper understanding of the science of corrosion here.

Corrosion Prevention Solutions

While traditional methods like surface-applied membranes offer some protection, structures that are already corroding and need long-term solutions require advanced technologies:

• Cathodic Protection (CP): 
• • Galvanic Cathodic Protection (GCP): This technology uses sacrificial anodes (typically zinc) that deliver a protective electrical current to the rebar and corrode in its place.
  • Impressed Current Cathodic Protection (ICCP): Ideal for large or heavily corroded structures, ICCP uses an external power source to deliver a protective current.

• Electrochemical treatments: Electrochemical treatments offer a powerful long-term approach to mitigating corrosion in reinforced concrete. These techniques, such as electrochemical chloride extraction and realkalization, utilize an applied electrical field to address the cause within the concrete.
  • Electrochemical Chloride Extraction (ECE): This innovative technique removes chloride ions from concrete, effectively "resetting" the structure. 
  • Electrochemical Realkalization: Realkalization is an electrochemical treatment specifically designed to combat corrosion in carbonated concrete. This process restores the high pH environment, reinstating passivity and effectively halting corrosion, thereby extending the service life of carbonated concrete structures.
• Fusion Technology: This technology takes a "best of both worlds" approach and provides very long-term corrosion protection by combining both galvanic and ICCP technologies. 

Real-World Success Stories

Autostrada Adriatica, Italy

Initially built in the '60s and expanded to accommodate heavier use over time, many of the tunnels retained original sections, which were tied into the newer concrete repairs. This, combined with exposure to atmospheric saltwater, made for a highly corrosive environment.

Vector Corrosion Technologies' Galvashield® XP4, CC, Fusion® T2, and SM-DAS anodes were deployed during the repairs to protect the tunnels from future corrosion. This project demonstrates the effectiveness of combining multiple CP technologies. You can read the entire project profile here.

Rainbow Bridge, Idaho

Decades of freeze-thaw cycles and application of de-icing chemicals lead to severe corrosion on this reinforced concrete bridge. It required significant rehab to improve the structure's safety while also ensuring it was protected and preserved because of its historical significance.

ECE and Galvashield® XP anodes were used to address chloride-induced corrosion and preserve the bridge's historical integrity. Read the complete project profile here.

Third Avenue Bridge, Minnesota

Surveys on the bridge revealed significant deterioration on the bridge deck, cap beams, arch ribs, and pier bases due to chlorides and freeze-thaw conditions. Galvashield® DAS, XP4, and Fusion® T2 anodes, along with activated arc spray zinc (ASZ) were implemented to help MNDOT achieve their goal of extending the service life of the Third Avenue Bridge by another 50 years.

Read the project profile here.

Looking to the Future

Vector Corrosion Technologies is at the forefront of concrete corrosion mitigation, continuously innovating to provide sustainable and effective solutions. We continue to advance the development and implementation of advanced technologies to extend the life of infrastructure.  

If you're facing corrosion issues in your concrete structures, our corrosion specialists can help identify the most effective approach. Whether you're looking for short-term protection or long-term corrosion mitigation strategies like cathodic protection, our experts can guide you in addressing your challenges. Contact us today to discuss how we can help protect and preserve your valuable infrastructure.

Learn more about how to preserve concrete structures for future generations here.