From Evaluation to Action: Creating Effective Corrosion Mitigation Designs for Parking Structures

The first step in an effective corrosion mitigation plan is understanding the root cause of corrosion. This can be achieved when inspections move beyond surface-level observations and data-driven testing is used to reveal conditions inside the concrete. The same approach is essential when assessing post-tensioned parking structures, where deterioration can progress unnoticed inside the concrete. With that foundation in place, the next step is designing a mitigation strategy that aligns with the actual needs of the structure and stops deterioration instead of simply shifting it to another location.

Among concrete infrastructure, parking structures are some of the most aggressive environments for conventionally reinforced and post-tensioned concrete. Chlorides from de-icing salts settle into cracks and joints. Moisture intrudes through areas where waterproofing systems have aged. Daily traffic loads create micro-cracking that allows chlorides and moisture to penetrate deeper into the concrete, accelerating chloride penetration. These combined conditions make durability management a challenge that often cannot be solved through targeted repair alone.

Why “Repair Only” Approaches Fall Short

Corrosion progresses quietly before it shows up as visible damage. Removing and replacing spalled or cracked concrete is necessary, but it does not remove chlorides in the concrete surrounding the repair. That contaminated region becomes the next corrosion hotspot, commonly referred to as the Halo Effect.  

This happens because:

• The concrete around the repair still contains chlorides leaving the steel at an elevated state of corrosion potential
• The new concrete within the repair creates an environment that passivates and protects the re-encapsulated steel.
• The steel in the new concrete and the steel in the existing concrete now sit at different electrochemical potentials, driving corrosion external to the perimeter of the repair area. Without targeted corrosion protection around the repair perimeter, deterioration simply relocates.
  
    

How Structural Condition Data Guides Mitigation Design

High-quality non-destructive evaluations such as half-cell mapping, chloride profiles and corrosion rate measurements (in addition to select targeted destructive testing methods such as cores and exploratory openings) can do more than simply define existing deterioration. They have the capability to reveal areas that are susceptible to future deterioration.  

Condition data helps identify:

• Zones with active corrosion
• Regions where chloride levels exceed corrosion threshold
• Areas with high moisture accumulation or poor drainage
• Tendon anchorages or reinforcement groups with elevated risk
• Locations that require immediate intervention versus preventive action

This information allows engineers to tailor where and how corrosion protection is applied.

  

What Does a Targeted Corrosion Mitigation Strategy Look Like?

Every parking structure requires a tailored approach. However, effective designs combine several strategies that work together to manage current deterioration and prevent future damage.

1.  Enhanced Concrete Repair

Repairing deteriorated reinforced concrete is often necessary but recall from earlier that traditional remove-and-replace alone is not always sufficient if the underlying deterioration mechanism is not addressed (ex. chloride contamination beyond the extent of the repair). Enhanced approaches to concrete repair may include:

• Installing type 1 embedded galvanic anodes around repair perimeters to mitigate the Halo Effect
• Improving bond and cover through proper concrete repair procedures as outlined by ACI and the ICRI

Collectively, these techniques help to prevent new corrosion from developing at the edges of the repair.

2. Corrosion Control in High-Risk Zones

Some areas don’t require concrete removal but still need corrosion protection. Stabilizing these regions helps extend service life and reduce future repair costs.

• Discrete type 2 embedded galvanic anode
• Distributed galvanic systems in elevated chloride areas
• Electrochemical treatments such as Electrochemical Chloride Extraction (ECE) or re-alkalization for widespread carbonation or chloride contamination
• Impressed Current Cathodic Protection (ICCP) system

Ultimately, the intent of these solutions is to protect reinforcement before damage becomes visible.

3. Integrated System Design

Parking structures often benefit from combining technologies. A tailored mitigation plan may include:

• Embedded type 1 galvanic anodes in repairs
• Adding type 2 embedded galvanic anodes to the parts of the structure where testing shows corrosion is likely to start
• Surface sealers, traffic membranes, and improved joint detailing
• For PT systems, protective anchorage repairs or corrosion control approaches that respect tendon integrity

Collectively, each component addresses a specific deterioration mechanism, and their performance depends on how well they are integrated.

4. Lifecycle and Maintenance Planning

Mitigation design doesn't end after installation. Long-term durability depends on regular monitoring and maintenance.

A complete plan includes:

• Defined inspection intervals
  • Periodic concrete sampling and corrosion potential testing
  • Verification of long-term corrosion protection performance
  • Adjustments based on environmental or usage changes

Altogether, this helps the structure stay ahead of deterioration rather than chase it.

Why a Tailored Design Matters

Parking structures that implement a tailored targeted mitigation plan consistently show:

• Significantly fewer repeat repairs
• Reduced risk of PT tendon distress
• Improved durability in high exposure zones
• Predictable maintenance budgets
• Longer intervals between major repairs

These results demonstrate the value of translating condition data into strategic corrosion mitigation design.

Bringing It All Together

The durability of a parking structure is not determined by a single repair or product. It comes from understanding the cause of deterioration, identifying the extent of corrosion activity, and applying the right protection measures exactly where they are needed.

A tailored corrosion mitigation strategy:

• Builds on the diagnostic foundation established in Part 1
• Addresses the unique challenges of both reinforced and post-tensioned systems presented on in Part 2
• Converts condition understanding into long-term durability planning
• Delivers predictable performance and reduced lifecycle cost for owners

This is the same philosophy that will be explored in depth in the upcoming webinar.

Join us for our next webinar!

Tailored Protection: Designing Targeted Corrosion Mitigation Solutions for Parking Structures

Join our experts as we discuss how to translate condition data into focused, long-lasting corrosion protection plans for parking structures. We will walk through practical examples, tailored design approaches, and answer your questions during a live Q&A.

Date: December 3, 2025
Time: 6:00AM – 7:00AM CST | 1:00PM – 2:00PM CST
Register: https://www.wesavestructures.info/events/category/Parking-Structure-Durability

This is the third session in The Parking Structure Durability Series, focused on designing smarter corrosion mitigation strategies that improve durability and reduce life-cycle costs for your parking assets.