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The Secret of MCI ® for Better Parking Ramp Maintenance

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Reading Time: 3 minutes

 

 

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One of the biggest enemies of parking ramp longevity is corrosion. Whether a parking ramp is in a warm coastal area subject to sea breezes and salt spray or whether it is in the frozen north with cars tracking in deicing salts every winter, the basic story is the same. Chloride-induced corrosion leads to premature deterioration and early repairs on the reinforced concrete structure. To change this story, Cortec ® recommends adding Migrating Corrosion Inhibitors (MCI ® ) into routine maintenance to slow down the corrosion process.

 

Preventative Maintenance versus Repair

Preventing a problem is usually easier and less expensive in the long term than repairing a problem. When it comes to reinforced concrete parking ramps, corrosion prompts repair because it swells the size of the rebar, placing pressure on the concrete overlay and eventually causing it to crack and spall off. The farther this process goes, the more damage is done and the more material- and labour-intensive the repair. While adding corrosion protection to a repair is important to help it last longer, slowing down corrosion as part of routine maintenance is even better because it can delay and reduce damage.

 

MCI ® Surface Applied Corrosion Inhibitors (SACIs)

MCI ® SACIs are ideal for parking lot maintenance because they penetrate and migrate through concrete pores and can be combined with water repellents or traffic membranes. MCI ® molecules are attracted to reinforcing metal, where they adsorb and form a hydrophobic layer that inhibits the ability of the metal to interact with corrosives such as moisture and chlorides. This molecular barrier delays the time to corrosion initiation and slows down the rate of corrosion that has already started. MCI ® can be applied at any stage of a parking ramp’s life cycle – before, during, and after repairs.

 

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Tips for Selecting the Right MCI ® SACI

Contractors and parking garage management companies can take a variety of paths when incorporating MCI ® into their preventative maintenance plan.

 

Those who want to aim for a 20-year MCI ® reapplication rate will typically want to choose MCI ® -2020 with a traffic membrane applied on top. Traffic membranes often have a 20-year warranty; however, when the membrane inevitably fails, it can allow water and chlorides to seep underneath and attack the concrete anyway. Applying MCI ® -2020 to the surface first will enhance protection by introducing the highest concentration of Migrating Corrosion Inhibitors of any SACI on the market.

 

For someone open to a corrosion-preventative maintenance period of seven to 10 years, MCI ® -2020 followed by MCI ® -2018 X is a good choice. This combination takes advantage of the highest concentration of surface-applied Migrating Corrosion Inhibitors topped by a 100% silane water repellent to keep MCI ® within and slow the ingress of corrosives.

 

For someone who wants to apply a two-in-one product, MCI ® -2019 or MCI ® -2018 are good options. MCI ® -2019 combines MCI ® with a 40% silane water repellent, making it ideal for tighter budgets. MCI ® -2018 combines MCI ® with a 100 percent silane water repellent for even better water repellency. These two SACIs are best applied in two coats, wet on wet, so there is no need to wait for dry time.

 

If a surface still has residual silane from a previous water-repellent application and it is not in the scope of the project to remove it, MCI ® -2019 can be used. This is because MCI ® -2020 and MCI ® -2018 may not penetrate a concrete surface that is partially covered with water repellents. However, MCI ® -2019 can be applied over residual silane water repellent with better penetration through the substrate.

 

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Start Your Preventative Maintenance Plan

Whatever a parking ramp’s age, it is not too early to start creating a corrosion-preventative maintenance strategy. Through the routine application of a water-repellent and Migrating Corrosion Inhibitor ™, parking ramp owners can push back the need for corrosion-related repairs and keep their parking structures in better condition longer to preserve property value.

 

 

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Fighting the Danger of Overprotection on Concrete Repairs

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Reading Time: 3 minutes
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Is it possible to give concrete too much protection against reinforcement corrosion? Research indicates that this is so, although no consensus exists on the exact mechanisms and how to avoid it. However, following logical reasoning, Cortec® recommends applying Migrating Corrosion Inhibitors to mitigate the problem.

What is overprotection?

Overprotection occurs when metal reinforcement in one part of the concrete is more protected than in another. This can happen when a new concrete patch is laid, replacing contaminated or carbonated concrete with uncontaminated concrete that has a high pH and therefore a naturally protective alkaline environment. The resulting difference in corrosion potential between the patch and the adjacent concrete eventually leads to corrosion in surrounding areas, thus transferring the original problem elsewhere. This is known as the ring anode/halo effect.

Examples of overprotection

Overprotection can also happen in a variety of other ways. One is through the common practice of cathodic protection (CP). The challenge of calculating the appropriate number of anodes for an area and removing concrete to install them is compounded by the fact that it is not possible to gain access to and treat all parts of the rebar equally.

 

This leaves some portions of the metal reinforcement with more protection than others, an imbalance that could show itself over time by corrosion in areas with less protection. A similar effect may happen with the application of an epoxy coating to one part of a rebar and not to another. Using other corrosion protection measures may cause a similar imbalance when over-applied.

 

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Even Out the Corrosion Potential

The use of MCI® Surface Applied Corrosion Inhibitors (SACIs) makes it easier to balance out the corrosion potential. Rather than leaving a well-protected patch surrounded by chloride-contaminated concrete, contractors can apply MCI® SACIs to the undisturbed concrete to reduce the difference in corrosion potential between the two portions.

 

Fortunately, MCI® SACIs are easy to apply by spraying onto the concrete like a standard surface treatment. As time progresses, Migrating Corrosion Inhibitors in the MCI® SACI work their way deeper in through the concrete pores toward the metal reinforcement. Their metal affinity allows them to form a protective molecular layer on the embedded rebar when they encounter it.

 

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MCI® SACI Options

MCI®-2020 contains the highest concentration of surface applied Migrating Corrosion Inhibitors on the market and is therefore the number one recommended SACI for this purpose. Typically, a coating or water repellent should be applied on top of this to keep moisture out and MCI® in.

 

Two-in-one MCI®/ water repellents are also available for greater convenience, albeit with smaller doses of Migrating Corrosion Inhibitors (MCI®-2018 combines MCI® with a 100% silane water repellent, and MCI®-2019 combines MCI® with a 40% silane water repellent).

Take a Balanced Approach to Corrosion Protection

Concrete repairs are too labour-intensive to make the mistake of overprotection. By being sure to protect the concrete around the patch area with Migrating Corrosion Inhibitors, contractors can take one step ahead of the chain reaction of corrosion that is common in less protected areas. Contact Cortec® to learn more about the advantages of mitigating corrosion in reinforced concrete with MCI®.