Concrete spalling happens when corrosion on embedded rebar expands so much that it causes the concrete cover to break and fall off. The only responsible response is to repair the gap and seek to slow down the corrosion process. But what are the best materials to use on the exposed rusted rebars? Here is a look at two popular options.

• 3K Bonding Agent

One commonly used product is a 3K material containing epoxy, corrosion inhibitor, and a bonding agent. These components are mixed and applied to clean metal reinforcement before the application of repair mortar. The coating works as a “glue” to bond the rebar or old concrete to the new patch material while also inhibiting corrosion on embedded reinforcement.

• CorrVerter^® MCI^®

CorrVerter^® MCI^® Rust Primer is a single component water-based primer that converts rusted surfaces to a passive layer using a combination of chelating agents and a high solids waterborne latex with extremely low water vapor permeability. It can be applied to rusty rebar and patched with a concrete repair mortar once the primer has dried.

Some of the key differences between the two products are summarized in the following table:

While both repair methods are valid, CorrVerter^® MCI^® offers obvious advantages in terms of reducing waste and simplifying labor. Which do you prefer? Contact Cortec® to learn more about the CorrVerter® MCI® advantage for spalling repairs!

Keywords: concrete repair, concrete spalling, concrete repair mortar, concrete bonding agent, rust converter, Cortec, From Grey to Green, MCI, CorrVerter, rebar coating

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New sights and industry opportunities greeted the Cortec® MCI® team at the 2023 ICRI Spring Convention, April 17th-19th in Vancouver, B.C. The conference theme of “Concrete Protection from the Sea to Sky: Waterproofing and Corrosion Protection” fit hand in glove with MCI® Technology on display at Cortec’s tabletop booth, where Ash Hasania (MCI® Technical Sales & Market Manager) and Jessi Meyer (VP Product & Technical Sales) greeted fellow industry professionals. The conference was well attended by all players in concrete repair—from engineers to contractors and manufacturers. It was a special pleasure to connect with Canadian professionals from B.C. and greater Canada whom we do not often get the chance to see at ICRI events in the U.S.!

Industry Best Practices and New Technologies

As usual, the conference offered an interesting array of technical sessions. Ash enjoyed being able to attend many of these and took special interest in presentations on (1) industry best practices for extending service life of concrete patch repairs and (2) new technology designed to pull chlorides out of concrete. ICRI Committees Cortec® also made its share of contributions to ICRI committees. A longtime member of the marketing committee, Jessi and fellow committee members were recognized for their efforts during the ICRI awards lunch. Ash took time to participate in proceedings for ICRI Committee 510 (Corrosion), ICRI Committee 310 (Surface Preparation), and ICRI Committee 160 (Life Cycle and Sustainability).

The corrosion committee spent much of its time discussing and finally voting on and approving its half-cell potential guide. They also talked about renewing one of the committee’s previously published guides.

The surface preparation committee stressed the importance of PPE when preparing concrete surfaces, discussed updating current technical guidelines, and talked about using technology to improve currently offered tools like the rebar evaluation app and concrete surface profile chips. The sustainability committee discussed how to deal with the challenge of getting projects submitted for sustainability and longevity awards and decided to be more proactive going forward by looking for candidates among applicants for other awards.

Even more significant was the committee’s discussion on creating a guide for sustainability and durability of concrete repairs. This is an area that remains very vague in regard to evaluating the sustainability of concrete repairs and how carbon emissions figure into the picture. Ash volunteered to be part of the new group that hopes to eventually create a meaningful guide to help industry players navigate these concerns.

Sightseeing in Vancouver

In addition to work, there were some great opportunities to enjoy the culture and natural beauty of Vancouver. Outings included a trip to Vancouver Art Gallery and a stroll through the treetops for some thrills and beautiful views at Capilano Suspension Bridge Park.

See You in the Fall!

All in all, Spring ICRI was a great time to connect, grow, and recreate with likeminded professionals. We wish our concrete industry friends and family a good construction season ahead and look forward to reuniting with you in Florida next October for the ICRI Fall Convention! Mark your calendars now!

2023 ICRI Fall Convention
October 16th-18th
TradeWinds Island Resorts
5500 Gulf Blvd.
St. Pete Beach, Florida 33706
United States

Keywords: 2023 Spring ICRI, sustainability, concrete repair, concrete corrosion, rusted rebar in concrete, Cortec MCI, From Grey to Green, concrete sustainability, ICRI committee activities, extend service life

For a PDF version please click here.

We are pleased to introduce our new MCI® Regional Sales Manager for the Midwestern United States! Rich Harsdorf joined Cortec® in February to oversee MCI® sales activities and accounts while working directly with clients in a region notorious for corrosion damage on concrete buildings and bridges.
With a Bachelor’s degree in chemistry and 16+ years working as a chemist and sales manager in the chemical industry, Rich is well-equipped to take on the challenge of protecting rebar in concrete from corrosion using MCI® Technology.

Rich is also passionate about developing positive relationships with his clients and making sure they are satisfied—even beyond their initial goals. “I believe the products Cortec® sell[s] offer a valuable solution to a problem,” Rich stated, “and I would love to introduce our products to customers in order to solve their problems.” He is ready to be proactive and supportive, placing customer needs before his own—even when it means putting in extra-long hours to finish the job.
If you work in the Midwest construction industry, Rich is here to support you in your quest for longer concrete service life with Cortec® MCI®. Contact him today for assistance—or simply to introduce yourself and welcome him onboard!

Rich Harsdorf
Regional Sales Manager, MCI®
Phone: 651-350-9536
Email: [email protected]

Keywords: rebar rust, concrete corrosion in Midwest, Cortec, MCI, From Grey to Green, Midwest construction industry, preventing corrosion in bridges, concrete corrosion, how to protect concrete from corrosion, how to extend concrete service life

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Are you tired of dealing with rusted rebar on the construction site and not sure where to turn for help? While rusted rebar can lead to serious problems with concrete adhesion and early corrosion, knowing when and how to address varying degrees of rust can make life on the construction site much easier. The tips below will give you and your colleagues a better understanding of rusty rebar problems and how to solve them.

Why So Much Rusted Rebar?

Fresh new metal surfaces are a magnet for corrosion and will continue to be so as long as they are exposed to moisture and oxygen. That is why rebar often reaches the construction site with at least a thin layer of flash rust. The situation only gets worse the longer the rebar sits outside in the construction yard, whether in a pile of raw materials or protruding from concrete where it was partially embedded before the construction project was put on hold.

How to Determine the Level of Flash Rust

Before deciding what to do about rebar rust, it is helpful to evaluate its severity. “A Guide to Flash Rust Prevention and Protection,” available for download from Corrosionpedia, offers some helpful tips for categorizing flash rust as light, moderate, and heavy. In addition to offering basic visual guidelines, the publication notes three tests that can be used for more detailed identification of the level of rust: the Brush Cloth Test, the Ten Tape Test, and the Tape Transmittance Test.

Decide which Mitigation Path to Take

Once the degree of rust has been identified, workers can decide which corrosion control method to adopt. The following options can be used as general guidelines, but the ultimate decision must be based on personal experience and good judgment.

Option 1: Do nothing. If the rebar only shows light rust, the Corrosionpedia flash rust guide says it may be possible to simply wipe it off with a cloth. At this stage, the cleaned rebar can go directly into a concrete mix enhanced with an MCI^® admixture such as MCI^®-2005.

Option 2: Apply MCI^® CorShield^® . If the flash rust is light but the rebar will be sitting out in the open for some time, the next best option is to wipe off the flash rust and apply MCI^® CorShield^®, a clear non-tacky temporary coating that does not need to be removed before concrete placement. MCI^® CorShield^® will slow down the corrosion process until the rebar is installed or the rest of the concrete is placed.

Option 3: Clean the rebar and apply MCI^®CorShield^®. If the rebar is moderately flash rusted, it may need to be cleaned off with a high-pressure rinse to remove most or all of the rust before coating. One of Corrosionpedia’s suggestions for countering corrosion during the water blasting process is to add corrosion inhibitors to blast water. By their nature, the corrosion inhibitors in a cleaner such as MCI^®-2060 fall under the guide’s classification of “passivators,” i.e., those corrosion inhibitors that leave behind a thin protective film to extend the window of time in which metal can be coated without flash rusting. Once the rust has been removed and the surface has dried, MCI^® CorShield^® can be applied for extended outdoor protection.

Option 4: Remove loose rust and apply CorrVerter^® MCI^®. If the rust is moderate to heavy and more than can be removed with a good pressure wash, CorrVerter^® MCI^® Rust Primer is another excellent option. After removing loose rust and cleaning the rebar, workers can apply this water-based coating directly onto the rusty rebar. CorrVerter^® MCI^® converts existing rust into a hydrophobic passive layer and discourages re-rusting, leaving the rebar with a clean fresh start for concrete placement. While you cannot completely stop rust, you can fight it and prevent it from doing as much damage as it could do otherwise. Finding rusty rebar at the construction site is not the end of the story, but neither should it be overlooked. While proper treatment of rusty rebar is an art, evaluating its severity and applying appropriate methods of cleaning, protection, and passivation, should leave you and other contractors much less overwhelmed by the sight of rusty reinforcing bars on the jobsite.

Contact Cortec^® to learn more about dealing with flash rust on rebar: https://www.cortecmci.com/contact-us/

Keywords: rusty rebar, tips for rusty rebar on the construction site, guide to flash rust, Cortec, CorrVerter, MCI, how to determine level of flash rust, corrosion inhibitors, corrosion control, add corrosion inhibitors to blast water

For a PDF version please click here.

With summer coming to the Northern Hemisphere, construction season will soon be in full swing. Although this is great for business, it raises new challenges for contractors pouring concrete at the hottest time of the year, when concrete sets faster than normal. Fortunately, the use of the right corrosion inhibiting admixture can keep this from turning into a nightmare.

Side Effects of CNI vs. MCI®

Calcium nitrite (CNI), once the industry standard for corrosion inhibiting admixtures, has the side effect of accelerating concrete set time, which makes the pressure of doing a perfect job all the more stressful for concrete contractors in hot weather. In contrast to CNI, MCI® (Migrating Corrosion Inhibitor™) concrete admixtures do not accelerate set time, making them a great option for summer heatwaves. Ready-mixers have seen outstanding results when pouring MCI®-2005 NS (normal set version) in the peak heat of summer, avoiding early set problems and even giving them the opportunity to remove set retarders. MCI®-2005, which has its own set-retarding effects, minimizes the need for set retarders even more. Two experiences in the summers of 2020 and 2021 highlight the advantages of MCI® admixtures from the contractor’s perspective.

Avoiding Cold Joints

In 2020, a contractor pouring a cast-in-place parking garage in Toronto was using a CNI admixture in the peak heat of summer. The concrete began setting too quickly and forming cold joints potential weak points for the future. When they switched to MCI®-2005 NS, they saw a major difference. They had no more early set problems— even at temperatures around 100 °F (38 °C)—and they were able to remove the set retarders needed for CNI. From that point on, they intended to use MCI®-2005 NS in place of CNI for any future projects where CNI was specified.

Best PT Mix Ever!

The following summer in Nebraska, one contractor was getting over the stress of a very difficult CNI concrete pour when another nightmare loomed: that of pouring a parking garage in the middle of a July heatwave. Fortunately, MCI®-2005 NS had already been selected as the corrosion inhibitor for the PT (post-tension) mix, but with a heat index of 100 °F (38 °C) at 9:30 in the morning, the contractor wondered if he should wait for cooler evening temperatures. At the reassurance of the MCI® regional sales manager, they went ahead with the pour, treating it as they normally would on a hot day with 2 ounces [59 mL] of set retarder. They also used slag as the supplementary cementitious material (reduces heat of hydration) and a high-range plasticizer to help with stiffness and slump. The crew soon noticed that the mix was much easier to place and consolidate than with CNI. In fact, they achieved an 8 inch (20 cm) slump and had significantly more bleed water than they had ever had with a CNI PT mix. The contractor’s general superintendent was so pleased that he called it the best PT mix he had ever used and said he never wanted to use the previous admix again. Just as he predicted, other ready-mixers in the area soon switched over to MCI®, as well, when they saw the good results.

Reduce the Stress This Summer

Pouring concrete is stressful enough without adding hot weather and CNI set acceleration into the mix. Minimize the stress this summer by choosing an MCI® admixture that does not accelerate set time and has a good reputation for workability, even in high temps. Contact Cortec® to learn more about using concrete admixtures in hot weather: https://www.cortecmci.com/contact-us/

Keywords: MCI admixtures, concrete admixtures, From Grey to Green, summer challenges for contractors, pouring concrete in hot weather, CNI accelerates concrete set time, corrosion inhibitors that do not accelerate set time, Cortec, Migrating Corrosion Inhibitor, how to avoid cold joints

For a PDF version please click here.

When you have a handbook, you want it to be as up to date and user-friendly as possible. That is what our MCI® Technology general brochure seeks to do in its most recent edition, which came hot off the press just in time for World of Concrete in January! Here’s a look at some of the highlights from our latest version.

New Visuals

If a picture is worth a thousand words, this brochure has more to say than ever. A QR code on the first page inside the brochure takes readers to our MCI® admixtures animation for a great intro to the basics of concrete corrosion and how MCI® Technology can help. Illustrations in the MCI® Product Application Guide have been enlarged to make it easier to see what concrete and MCI® treatment may look like at different stages in the structural life cycle. An expanded specialty products section includes new images that tell a much clearer story on where and how these MCI® solutions can be used.

Relevant Certifications and Guidelines

Another improvement is the referencing of certain key certifications and guidelines that apply to MCI® products. For example, some MCI® Technologies have received CE certification (for purchase in the EU) or have been certified to meet ANSI/NSF Standard 61 certification for use on drinking water system components. The text also refers to ACI 212.3 and ICRI Guideline No. 510.2-2019, two important industry standards that recognize the underlying chemistry of MCI® in their discussions of corrosion inhibiting admixtures and surface applied corrosion inhibitors (SACIs), respectively.

Updated Charts

Updated charts are also a plus. For example, the MCI® admixture comparison chart has been expanded to include an additional admixture chemistry. A completely new chart has been added that defines pure MCI® inhibitors versus MCI® water repellents and identifies which MCI® SACIs fall under each category. The product selection guide has been updated to remove obsolete technologies and include new ones, such as our most recent MCI® repair mortar additions. Furthermore, better labeling makes it easier to navigate specialty products by clearly identifying each product type (e.g., cleaners, coatings, injectable gels).

A Great Educational and Selling Tool!

After some serious reflection by our team on how to make it better, our MCI® brochure has emerged as more up to date, usable, and relevant. It is a great tool for educating yourself, colleagues, and clients as you move forward in your journey of enhancing concrete durability and sustainability with MCI®. Click here to view the updated brochure now: https://www.cortecmci.com/wp-content/uploads/2023/01/MCI_Gen_Brochure_01-2023_Final.pdf

Keywords: MCI, Cortec, From Grey to Green, sustainability, structural life cycle, concrete admixtures, MCI technology brochure, repair mortar, concrete corrosion, SACI

For a PDF version please click here.

Cortec® Corporation is pleased to announce that Kevin Quan (MCI® Regional Sales Manager, East Coast) has been elected to two local boards of the International Concrete Repair Institute (ICRI). After seeing the value of membership with local chapters, Kevin has joined the leadership team on the boards for the ICRI Delaware Valley and ICRI Baltimore/Washington DC chapters.

From Sacrificial Concrete to Concrete Repair

Kevin, who has a B.S. in Mechanical Engineering and an Executive MBA, brings a lot to the table with more than two decades in Sales and Marketing for a variety of industries. Interestingly, 15 of those years were spent promoting the “opposite” of concrete repair, as Kevin worked for a company that made sacrificial, crushable concrete pads designed to capture and save airplanes that had gone off the runway. Since joining Cortec® in 2021, his focus has shifted to the other extreme of using MCI® Technology to promote sustainability and to increase durability of concrete. This dovetails perfectly with the goal of ICRI to promote concrete restoration, and Kevin quickly recognized the value of being involved in local ICRI chapters when he became a member in September 2021. Fellow members soon noticed his strong interest and active involvement in the organization, as well, and were ready to vote him into a leadership position where he could promote that value to others.

Amplifying the Value of ICRI

Kevin’s underlying responsibility for the next three-year term will be to promote awareness of ICRI membership value to the industry while helping implement ICRI initiatives and enhancing the value of ICRI to its members. Kevin will start his term by serving on the membership committee at the ICRI Delaware Valley Chapter. He will also be co-chair of both the golf committee and the newsletter and communications committees at the Baltimore/Washington DC Chapter this year. By serving on multiple boards at once, he hopes to be able to share best practices from chapter to chapter.

Cortec® expects Kevin to be a strong contributor and collaborator in these new positions and looks forward to seeing the chapters grow under his leadership contribution. Please join Cortec® in congratulating Kevin and cheering him on in these new roles!

Learn more about the involvement of our Cortec® MCI® team in ICRI by contacting us: https://www.cortecmci.com/contact-us/

Keywords: Cortec, MCI, ICRI, concrete repair, ICRI Delaware Valley, ICRI Baltimore, concrete restoration, structural durability, value of ICRI membership

For a PDF version please click here.

We are pleased to introduce our new surface prep guide for MCI® surface applied corrosion inhibitors (SACIs)! While MCI® SACIs are a great way to extend the service life of concrete structures, success hinges heavily on proper concrete surface prep. With this in mind, our MCI® team has designed a surface prep guide to help contractors and building owners get the most out of their MCI® SACI application to mitigate rusted rebar in concrete.

What the Surface Prep Guide Has to Offer
The MCI® surface prep guideline starts with a rundown on the basics of concrete surface prep:*

1. Remove loose or cracked concrete down to sound concrete.
2. Allow 28 days (preferably) for the concrete to cure before coating.
3. Make sure the surface is clean using a suggested cleaning method.

What follows is a chart noting coverage rate, recommended surface prep, and special remarks on each SACI listed. In some cases, surface prep tips include ideal CSP (concrete surface profile) levels that can be identified based on CSP chips available from ICRI (International Concrete Repair Institute). Other remarks cover product specifics such as ideal number of coatings or surface moisture level. The guide also includes surface prep recommendations for two MCI® coatings that can be used on rebar.

How You Can Benefit from This Guide
If you apply MCI® SACIs or know someone who does, this guide is a great place to start finding surface preparation best practices at your fingertips in online or printable format. Be sure to bookmark this resource for your own use and to share with clients in need of MCI® surface prep guidance! https://www.cortecmci.com/surface-preparation-guide-for-mci-products/

Keywords: Migrating Corrosion Inhibitor, surface applied corrosion inhibitor, rusted rebar in concrete, concrete corrosion, concrete surface prep, concrete repairs, Cortec, MCI, ICRI, concrete surface profile chips

*Please note: all concrete repairs should be done in accordance with professional engineering advice.

For a PDF version please click here.