CASE HISTORY SPOTLIGHT: Case History #62: Cooling Tower Restoration

A processing facility faced the question of whether they could save the structural integrity of deteriorating, corrosion-damaged concrete cooling towers instead of replacing them at significant cost. The question was answered with an MCI® concrete repair. First, loose concrete was jet blasted off. Heavy corrosion was removed from rebar using VpCI®-423. MCI®-2023 was immediately applied to clean rebar for protection. MCI®-2038 and MCI®-2039 were used to repair concrete and restore structural integrity. Areas that did not need to be repaired were sprayed with MCI®-2020 to migrate and protect underlying steel from corrosion. The work restored the structural integrity and appearance of the concrete cooling towers at a significant cost savings compared to replacement.


To read the full case history, please visit: https://www.corteccasehistories.com/?s2member_file_download=access-s2member-level1/ch062.pdf

Keywords: cooling tower restoration, corrosion damaged concrete, concrete cooling towers, MCI, concrete repair, MCI-2020, structural integrity, cost
savings, rebar corrosion, corrosion removal

For a PDF version please click here.

NEWS ALERT: MCI® PTC® Emitters – Go Beyond Reinforced Concrete Protection!

Did you know that the benefits of MCI® Technology extend beyond reinforced concrete? While Migrating Corrosion Inhibitors are most commonly used to mitigate the corrosion of embedded rebar in new or existing concrete, they offer much broader benefits, as demonstrated by PTC Emitters.

How PTC Emitters Work
PTC Emitters are breathable pouches that contain Migrating Corrosion Inhibitor™ powder. They can be placed in any void space enclosure where corrosion protection is needed. The MCIs vaporize through the pores of the pouch, diffuse throughout the space, and finally form a protective molecular layer on surrounding metal surfaces. Distribution of the MCI® vapors in large spaces can be enhanced by blowing dry air through the pouches, if needed.

Designed to Protect Suspension Cables
PTC Emitters were initially designed to mitigate corrosion on suspension bridge cables. These cables are made of many metal strands twisted together
with voids that can capture moisture and foster corrosion between the strands. Dehumidification systems are sometimes used to force dry air through these cables in an effort to reduce moisture and stave off corrosion. PTC Emitters are a perfect backup to the deficiencies of dehumidification. They can be easily placed in chambers added to the dehumidification piping for the purpose of blowing Migrating Corrosion Inhibitors throughout the intricacies of the suspension cable strands.

One Technology, Many Uses
PTC Emitters can also be adapted to many other construction/structural applications where metal needs corrosion protection inside a void space:

  • Tubular structures, pipes, and vessels
  • Segmental concrete bridge tendons/cables
  • Reinforcement inside box girder segments

If you work in construction or structural maintenance, be sure to contact us for more information and ideas on how PTC Emitters can provide the corrosion protection needed in your various applications. Learn more: https://www.cortecmci.com/contact-us/

Keywords: structural void space corrosion, suspension bridge cables, suspension bridge corrosion, dehumidification systems, Cortec, MCI, Migrating Corrosion Inhibitors, rebar corrosion, corrosion protection

For a PDF version please click here.

CASE HISTORY SPOTLIGHT: Case History #376: Emergency Stabilization of Alcatraz

ch 376.2 scaled

The historic Alcatraz Federal Penitentiary is located on an island in San Francisco Bay. The perpetual environment of saltwater and fog has caused many corrosion problems for the National Park Service (NPS), who oversees the site. In 2008, the NPS realized something had to be done to slow down ongoing corrosion and remove loose concrete that could fall off high prison building walls and threaten visitor safety. The work was complicated by a limited budget and the designation of Alcatraz as a bird sanctuary where the bird habitat must not be disturbed by maintenance activity from February through September.
NPS worked around the difficulties by contacting their Cortec® distributor for solutions. The repair ultimately involved removing spalled concrete, coating exposed steel with CorrVerter®, and applying MCI®-2020 to mitigate unseen corrosion beneath the surface. The products were easy to apply and cost-effective. Also, the fact that they could treat larger areas presented NPS with a potential cost savings on future repairs.

To read the full case history, please visit:
https://www.corteccasehistories.com/?s2member_file_download=access-s2member-level1/ch376.pdf

Keywords: Alcatraz, historic San Francisco, corrosion problems, cost savings on repairs, saltwater corrosion, limited budget solutions, Cortec, CorrVerter, MCI, MCI-2020

For a PDF version please click here.

Get Ready to Take a Fresh Look at High Performance Concrete Repairs!

CorrVerter Application

Cortec® is pleased to announce a fresh new look to its MCI® HPRS® brochure! The acronym HPRS® stands for “High Performance Repair Systems,” which use MCI® Technology to enhance the durability of concrete repairs. By following the recommendations of the updated MCI® HPRS® brochure, engineers, contractors, and DOTs can take a path to longer lasting repairs and extended concrete structural service life.

Enhance Concrete Repair Durability
The MCI® HPRS® brochure starts with a brief overview of MCI® Technology, centered on the action of Migrating
Corrosion Inhibitors. These are able to diffuse throughout concrete pores in liquid and/or vapor form to protect anodic and cathodic areas of embedded metal reinforcement. MCI® forms a protective molecular layer on metal surfaces and significantly reduces corrosion rates, leading to a longer service life for the structure.

Combat the Ring-Anode Effect
Next, the brochure explains how MCI® evens out the corrosion potential between areas of new and old concrete to combat the insidious ring-anode effect. This problem arises because of the relatively higher pH and resistivity of new patch areas compared to old concrete. The difference in corrosion potential causes corrosion to accelerate in concrete adjacent to the repair. MCI® migrates to these surrounding areas to minimize the halo effect.

Concrete Repair Instructions
After a brief description of each HPRS® component, the brochure lists updated step-by-step instructions on how to include MCI® in
a concrete repair:

1. Prepare the Substrate
2. Treat and Clean Rusted Rebars
3. Application of Repair Materials
4. Surface Applied Corrosion Inhibitor Application
5. Final Coating

Each step identifies which HPRS® components should be used and where it should be applied after the substrate has been properly prepared in Step 1. For example, CorrVerter® MCI® Rust Primer is recommended for passivation of rusted rebars under Step 2. Step 3 summarizes the use of MCI®-2039 repair mortar for horizontal repairs, MCI®-2040 repair mortar for vertical and overhead repairs, and MCI®-2044 concrete mix for
form and pour applications. Step 4 identifies two surface applied corrosion inhibitor options—either MCI®-2020 as a pure corrosion inhibitor for extra protection on the cured patch, or a two-in-one MCI® water repellent / surface applied corrosion inhibitor for repairs where no membrane or coating system will be used. Step 5 recommends MCI® EcoRainbow® Architectural Coating as a final coat over surface applied corrosion inhibitors to seal out water and carbonation while providing a great finished look.

Implement the Latest MCI® HPRS® Strategy
Ultimately, concrete repair is a necessary fact of life. Fortunately, contractors, DOTs, and engineers can go a long way toward maximizing the durability of their concrete repair through strategic use of the tips and materials outlined in the latest MCI® HPRS® brochure.
Browse the updated brochure today for fresh ideas: https://www.cortecmci.com/wpcontent/uploads/2022/01/HPRS_01-2022_red.pdf

Keywords: Cortec, MCI, concrete repair, ring anode effect, halo effect, rusted rebar, repair mortars, water repellents, surface
applied corrosion inhibitors, Migrating Corrosion Inhibitors

Need a High-Resolution Photo? Visit: www.cortecadvertising.com

For a PDF version please click here.