Maximizing Seawall Service Life with Strategic Corrosion Inhibiting Construction and Repair!

Maximizing Seawall Service Life with Strategic Corrosion Inhibiting Construction and Repair MCI®-2020

August 30, 2021

Seawalls are important structures typically designed to protect buildings from tides, waves, coastal flooding, and shoreline erosion. The use of seawalls is on the rise and expected to increase along with rising sea levels. In addition to their vital role of protecting assets and properties from water attack, seawalls have a crucial need for proper protection and maintenance themselves. This is especially true because of constant exposure to a naturally corrosive environment-water, chlorides, and humidity-that gradually deteriorates and destroys the reinforced concrete structure. To maximize service life and keep the seawall from total destruction, taking strategic steps to inhibit corrosion with Cortec® Migrating Corrosion Inhibitor™ Technology at the time of construction and repair is strongly recommended.

New Seawall Construction
Seawalls are expensive structures and therefore must be durable enough to justify the long-term investment required in the first place. A reasonable service life for a seawall would typically be 50+ years. However, actual service life may be much less depending on the concrete mix used and the deteriorating effects of accelerated corrosion. Adopting the right design mix in conjunction with MCI®- 2005 or MCI®-2005 NS is expected to increase the service life by three to four times and reduce the cost of maintenance. MCI®-2005/2005 NS admixtures work by forming a protective molecular layer at the level of the rebar to delay time to corrosion and reduce corrosion rates inside the concrete once started. For one property owner in Longboat Key, Florida, seawall corrosion prevention meant adopting a Florida DOT concrete mix along with MCI®-2005 to achieve a service life prediction of more than 150 years. The original mix design had fallen far short to an expected 15.2 years before the first repair. Adding MCI®-2005 tripled the prediction to 46.9 years. Because the owner initially set his sights extra high on a 100-year design life, the original mix was replaced with one used by the Florida DOT having a lower water/cement ratio and pozzolans added. This itself brought the service life prediction to more than 100 years. The addition of MCI®-2005 extended the service life prediction even farther, beyond 150 years. MCI®-2005 also offered environmental benefits as a USDA Certified Biobased Product that is UL certified to meet ANSI/NSF Standard 61 for use in structures containing potable water (other admixtures such as calcium nitrite are more watersoluble and therefore more likely to leach into surrounding water). 

Rehab of Existing Seawall Structures
Existing seawalls require a different approach that implements corrosion mitigation chiefly at the time of repair. Concrete cracking, spalling, delamination, and rust stains are signs that corrosion has begun and repair is needed. Repair can be challenging due to moisture levels inside the concrete and changes in sea levels due to tides, splashing, and waves. However, addressing corrosion and concrete durability concerns alongside material repairs is critical to achieving service life requirements. The suggested repair system for concrete above and below the waterline are as follows and should be implemented in conjunction with proper preparations per ICRI guidelines.

Repairs Above the Waterline
• Apply CorrVerter® MCI® Rust Primer to exposed reinforcement.
• Mix MCI® Mini Grenades into repair mortar.
• Apply MCI®-2020 to the surface of the repaired and finished concrete.
• Apply MCI®-2018 over MCI®- 2020 as a water repellent (note: MCI®-2018 is breathable and allows for vapor transmission, which means it will not  trap the existing moisture, but will allow it to escape while simultaneously repelling external water).

Repairs Below the Waterline
• Apply CorrVerter® MCI® Rust Primer to exposed reinforcement.
• Mix MCI® Mini Grenades into repair mortar.
• Apply MCI®-2020 to the surface of the repaired and finished concrete, water-rinsing the surface after application.
• Seal with a waterproofing coating to keep moisture out.

By incorporating corrosion preventative measures into new construction and repair, seawall owners can maximize the service life of these important structures by helping them endure constant attack from corrosive elements. Contact Cortec® MCI® for further guidance on your specific construction or repair project: https://www.cortecmci.com/contact-us/

Keywords: corrosion inhibiting admixtures, surface applied corrosion inhibitors, SACI, construction, concrete repair, concrete corrosion, rebar corrosion, MCI, migrating corrosion inhibitors, concrete spalling, water repellent, seawalls

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MCI-2020 Gel Delivers Robust Corrosion Protection to the Depth of Steel Reinforcement

MCI®-2020 Gel Delivers Robust Corrosion Protection to the Depth of Steel Reinforcement

August 24, 2021

Corrosion of metal reinforcement is one of the most serious threats to the durability of concrete structures. While many excellent technologies delay and mitigate the effects of corrosion on embedded reinforcement, there are fewer options when corrosion takes place deep inside concrete. Is such difficult-to-access corrosion beyond the reach of existing treatments? Cortec® Corporation answers that question with a resounding “no!” in the form of MCI®-2020 Gel, designed to penetrate to the heart of a structure’s corrosion problem.

MCI®-2020 Gel Delivers Robust Corrosion Protection to the Depth of Steel ReinforcementMCI®-2020 Gel is an injectable corrosion inhibitor which provides a robust dose of corrosion protection directly at or near the depth of steel reinforcement in concrete. MCI®-2020 Gel utilizes the time-proven chemistry of Cortec’s Migrating Corrosion Inhibitor™ (MCI®) Technology to migrate to steel reinforcement from injection locations. Once at the reinforcing steel, MCI® molecules deposit across the metal surface to form a molecular layer which acts as a barrier to corrosive elements such as chlorides. This technology has many advantages:

Targeted applicationMCI®-2020 Gel can be applied at customizable depths to meet the needs of a structure, directly targeting problem locations and reducing time needed for migration of the inhibitor
• Minimally invasiveInjection holes can be drilled smaller than for comparable products in many cases
• Economical to install and maintainHoles can be capped for easy reapplication or sealed with repair mortar as desired
• Attractive safety benefitsMCI®-2020 Gel is non-flammable, non-combustible, and does not contain secondary amines or nitrites (which together can form carcinogenic nitrosamines).

 

There are many situations where MCI®-2020 Gel provides a welcome solution because of the difficulty of transporting corrosion inhibitors to the level of the rebar. For example, structures with inconsistent or thick concrete cover or multiple layers of reinforcing steel will require protection beyond the reach of topical treatments. Structures with sealers or tile facades present a physical barrier to the application of a surface applied corrosion inhibitor (SACI) and also need a different approach. MCI®-2020 Gel penetrates beyond these obstacles to deliver corrosion protection to the depth required. Suggested applications where this may be needed include

• Below grade tunnels
• Window lintels
• Buildings with facades
• Residential buildings
• Structural walls and equipment bases
• Parking decks, ramps, and garages
• Marine structures, dams, or piers
• Balconies, decks, retaining walls, and lanais

Corrosion of concrete reinforcement is an insidious problem that ultimately reveals itself in cracking and deteriorating structures. Arresting corrosion at the root level before it proceeds too far can be difficult but no longer impossible in hard-to-access locations thanks to MCI®-2020 Gel. Contact Cortec® to discuss how it could apply to your own deep-seated corrosion issue: https://www.cortecmci.com/contact-us/

Learn more about MCI®-2020 Gel here: https://www.cortecmci.com/product/mci-2020-gel/

Keywords: concrete, corrosion, spalling, rebar corrosion, service life, concrete repair, concrete maintenance, Migrating Corrosion Inhibitors, MCI, Cortec, structural durability, SACI

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MCI®-2005 NS Admixture Recently Approved by Three New DOTs!

MCI®-2005 NS Admixture

August 17, 2021

MCI®-2005 NS corrosion inhibiting admixture has recently been approved for DOT use in three more states! This is exciting news for engineers in Pennsylvania, Maine, and Massachusetts who can now specify an industry leading admixture in their concrete design mixes for new construction and repair of roads, bridges, and other public transportation infrastructure. MCI® is one of
the easiest and most cost-effective ways to build a longer service life into a new or existing structure and hence can have beneficial ripple effects on budget and safety concerns long-term.

Corrosion: A Serious Threat to Infrastructure
According to the 2021 Report Card for America’s Infrastructure,* 42 out of every 100
bridges in the U.S. are 50 years old or more and 7.5% are in “poor” condition, meaning ongoing
repair will be needed for years to come. As new projects develop, engineers will likely place an
increasing focus on building structures to last longer. One major threat to extended service life is corrosion of embedded reinforcing metal in concrete that eventually cracks and pushes away the concrete cover, causing the structure to deteriorate. Migrating Corrosion Inhibitor
™ Technology mitigates this problem by delaying corrosion onset and reducing corrosion rates once started.

 

MCI®-2005 NS Admixture

 

Normal Set MCI® Admixture
MCI®-2005 NS is one of Cortec’s most popular normal-set water-based organic corrosion inhibiting admixtures. It meets all requirements of ASTM C1582. When incorporated into concrete, MCI®-2005 NS forms a protective molecular layer on embedded metals to inhibit corrosion. In new
construction, this is quantified by an increase in critical chloride threshold and subsequent reduction in corrosion rates after corrosion initiates. When used with repair mortars and grouts, MCI
®-2005 NS not only protects rebar within the patch; it is able to migrate into undisturbed concrete adjacent to the repair to protect reinforcement already in place. Unlike traditional calcium nitrite (CNI) admixtures, MCI®- 2005 NS admixture can be dosed independently of expected chloride loading and does not accelerate set time—a critical factor for finishing crews, especially in hot weather.

DOT Approvals in North America
DOT approvals not only expand the potential reach of where MCI® can be used for transportation infrastructure; they also lend credibility for use in projects that do not require DOT approval (e.g., parking garages). In addition to the recent acceptance of MCI®-2005 NS by MaineDOT, MassDOT, and PennDOT, MCI® Technology/admixtures have been approved in a variety of other states and provinces over the years.

These include
• British Colombia (MCI®-2005, MCI®-2006)
• California (MCI®-2005 NS)
• Colorado (MCI®-2005 NS)
• Idaho (MCI®-2000, MCI®-2005, MCI®-2020)
• Iowa (MCI®-2005 NS)
• Kentucky (MCI®-2000, MCI®-2005, MCI®-2005 NS)
• Maine (MCI®-2005 NS) – New approval!
• Massachusetts (MCI®-2005 NS) – New approval!
• Minnesota (MCI®-2005 AL, MCI®-2005 NS)
• Nebraska (MCI®-2020)
• Ohio (MCI®-2005, MCI®-2005 NS)
• Ontario (MCI®-2000, MCI®-2005 NS, MCI®-2005 AL)
• Pennsylvania (MCI®-2005 NS) – New approval!
• Quebec (MCI®-2000)
• South Carolina (MCI®-2000, MCI®-2005, MCI®-2005 NS, MCI®-2006 NS)

Of special note are states/provinces known for harsh winters (high use of deicing salt) or coastal environments, both of which take a heavy toll on reinforced concrete structures and require strategic anti-corrosion planning. Since application processes and renewal requirements vary by state, engineers should check each DOT’s qualified product list for the most up to date information and new developments before starting a project. Meanwhile, the expansion of MCI® DOT approvals to three more states is an exciting opportunity for engineers to take advantage of one of the best, most cost-effective and easy to work with corrosion inhibiting technologies on the market!

Contact Cortec® MCI® to learn more: https://www.cortecmci.com/contact-us/

*See https://infrastructurereportcard.org/cat-item/bridges/

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Surface Applied Corrosion Inhibitors (SACIs): Comparing “Apples to Apples” vs. “Apples to Oranges”

Surface Applied Corrosion Inhibitors (SACIs): Comparing "Apples to Apples" vs. "Apples to Oranges"

August 10, 2021

When it comes to selecting Surface Applied Corrosion Inhibitors (SACIs) for concrete repair and maintenance, it is important for engineers to know how and why to compare “apples to apples” instead of “apples to oranges.” The International Concrete Repair Institute (ICRI) Technical Guideline No. 510.2-2019, “Guideline for Use of Penetrating Surface Applied Corrosion Inhibitors for Corrosion Mitigation of Reinforced Concrete Structures,” provides a good place to start. From there, Cortec® Corporation helps engineers sort through the many varieties of “produce” on the market to help engineers compare “apples to apples” instead of “apples to oranges” and pick the product best suited to the job.

Sorting Out “Apples from Oranges”

The ICRI guideline defines SACIs as liquids that penetrate concrete to the depth of embedded reinforcement and actively mitigate corrosion on the steel surface. These SACIs include amine-based corrosion inhibitors that travel in the vapor phase through the concrete pore structure and form a molecular protective layer on the rebar. Surface applied products that contain only water repellents do not qualify. Standard water repellents penetrate only millimeters into the concrete; SACIs must penetrate as much as several inches. Water repellents recognized in the ICRI document contain the addition of amine-based corrosion inhibitors that can penetrate deeper into the concrete to reach embedded reinforcing steel. The document also includes pure corrosion inhibitors (neat inhibitor in a solvent, generally water) that are not water repellents. The difference is also explained in the figures below.

Generally speaking, the amount of corrosion inhibitor is highest in pure SACI products, and lower in water-repellentbased SACIs (but these materials have the added water repellency feature that allows them to be used as a two-in-one material). Water-repellent SACIs generally have a corrosion inhibitor concentration ranging from 1-10%, depending on the manufacturer, whereas a pure corrosion inhibitor with no water repellent typically ranges from 15-25% corrosion inhibitor concentration. Engineers who want corrosion protection at the level of the rebar, with or without water repellency, must be able to tell the difference between these products in order to specify the ones that will provide the most effective protection to the embedded reinforcement on the structures they are working on.

Comparing “Apples to Apples” vs. “Apples to Oranges”

Once engineers understand the difference between individual SACI products for concrete surface applications, they will be ready to compare “apples to apples” materials for their specific scenario. For instance, parking structure and bridge repairs often include the application of a traffic deck membrane or other coatings that are impermeable to water, chlorides, and other contaminants, as part of a protective “system” that also requires active corrosion inhibitors beneath the coating. In this scenario, the specifier might consider using pure SACI versus water-repellent-based SACI in order to get more
penetrating corrosion inhibitor into the concrete while still protecting against ingress of contaminants with the topcoat system. In situations where a topcoat is not used, the specifier might prefer to recommend water repellent-based SACI as a two-in-one solution. Specifying “apples to apples” would mean selecting pure SACI products as alternatives to each other, or water-repellent-based SACIs as alternatives to each other. “Apples to oranges” would mean specifying the use of a pure SACI as an alternative to a water-repellent based SACI.

SACIs from Cortec® Corporation

Cortec® Corporation offers the following SACIs as part of its MCI® Technology line to extend concrete service life:
Full-Strength SACI, No Water Repellent

MCI®-2020 is a top-of-the line option for use where a pure, high concentration penetrating corrosion inhibitor is needed. It is also available as MCI®-2020 V/O (for vertical/overhead use) or MCI®-2020 Gel (for injection beneath surfaces that cannot be disturbed or properly prepared).

Two-in-One Water Repellent SACIs

• MCI®-2018 (100% silane)
• MCI®-2019 (40% silane)
• MCI®-2021 (silicate)
• MCI®-2022 (silane/siloxane blend)

Contact Cortec® MCI® to learn more: https://www.cortecmci.com/contact-us/

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Cortec Laboratories Offers Accredited ASTM G180 Testing for Corrosion Inhibiting Admixtures!

Cortec® Laboratories Offers Accredited ASTM G180 Testing for Corrosion Inhibiting Admixtures!

August 4, 2021

It is increasingly clear that steps must be taken to enhance the durability of concrete structures. Engineers today are designing new structures expected to last over a century, while owners of existing structures that are reaching the end of their designed service life are looking for ways to maintain them for further use. Corrosion of metal reinforcement is a critical risk factor for durability of structures, and as such, the development and selection of corrosion inhibiting admixtures is a consideration to take seriously. Cortec® Laboratories can assist stakeholders in the all-important screening process by performing accredited testing to ensure admixtures measure up to widely accepted industry standards for the selection and qualification of corrosion inhibiting admixtures. One such test is  G180, a corrosion inhibition test measurement option under ASTM C1582, Standard Specification for Admixtures to Inhibit Chloride-Induced Corrosion of Reinforcing Steel in Concrete.

 

Reasons for ASTM G180 Testing

ASTM G180 testing may be needed for a variety of reasons. First, manufacturers use it to screen new chemistry formulations for their potential as corrosion inhibiting admixtures. In the United States, admixture formulations need to pass ASTM C1582 to qualify as a corrosion inhibiting admixture. This standard specifies use of either ASTM G180 or ASTM G109 to measure corrosion inhibition ability in chloride environments. Admixtures need to pass at least one of these in order to be classified as a corrosion inhibiting admixture. Chemistries that pass ASTM G180 testing, which is conducted over the course of three days, have a strong vote of confidence for their corrosion inhibiting ability; whereas those that do not pass this quick test must undergo years of additional testing under ASTM G109. Other times, ASTM G180 is needed simply for quality assurance of existing products and/or as part of an audit like the one recently performed by Cortec® Laboratories on MCI®-2005 for Cortec® Middle East and Dubai Municipality. Finally, ASTM G180 testing is also critical for engineers working with DOTs who require corrosion inhibitors to pass ASTM C1582 before use on their projects. Whatever the case, Cortec® Laboratories can provide the needed testing through its independent ISO 17025 accreditation to perform ASTM G180.

 

MCI®-2005 Passes ASTM G180

ASTM G180 Linear Polarization Curve for MCI®-2005
ASTM G180 Linear Polarization Curve for MCI®-2005

While Cortec® Laboratories is ready to test any admixture, MCI®-2005 is one of special note that passes ASTM G180 testing and is ideal for new construction. MCI®-2005 is an organic corrosion inhibitor that contains a blend of amine salts of carboxylic acids. Unlike calcium nitrite admixtures, which have a set accelerating effect that can send workers scrambling or cause early setup problems, MCI®-2005 slightly delays set time, making the concrete easier to work with and reducing the heat of hydration. Other advantages are that MCI®-2005 contains 67% USDA certified biobased content and is certified to meet ANSI/NSF Standard 61 for use in large potable water structures.

When incorporated into concrete, MCI®-2005 forms a protective molecular layer on embedded metals to inhibit corrosion. In new construction, this is quantified by an increase in critical chloride threshold and subsequent reduction in corrosion rates once corrosion initiates. When used with repair mortars and grouts, MCI®-2005 not only protects rebar within the patch, but it is also able to migrate into undisturbed concrete adjacent to the repair to protect reinforcement already in place.

 

Learn More about ASTM G180 Testing

Whether looking to test MCI®-2005 or another admixture for an upcoming project, stakeholders can learn more about how ASTM G180 testing is done by viewing the video recently made by Cortec® Laboratories. Contact your local MCI® rep to learn more or arrange testing: https://www.cortecmci.com/contact-us/.

 

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Cortec® Corporation is the global leader in innovative, environmentally responsible VpCI® and MCI® corrosion control technologies for Packaging, Metalworking, Construction, Electronics, Water Treatment, Oil & Gas, and other industries.  Our relentless dedication to sustainability, quality, service, and support is unmatched in the industry. Headquartered in St. Paul, Minnesota, Cortec® manufactures over 400 products distributed worldwide.  ISO 9001, ISO 14001:2004, & ISO 17025 Certified. Cortec Website: http://www.cortecvci.com Phone: 1-800-426-7832   FAX: (651) 429-1122

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