Cortec's latest corrosion inhibitor provides a two-pronged approach to protecting structures, by reducing the porosity of concrete and by directly shielding the steel reinforcement.
Cortec Corporation, a global leader in corrosion control technologies, has launched an integral waterproofing and corrosion-inhibiting admixture designed to prevent or delay corrosion of steel reinforcement in new concrete structures.
The MCI-2012 IntegraPel is a water-based organic admixture that uses a two-pronged approach to protect embedded steel. It reduces the intrusion of corrosive agents into the concrete and provides a self-replenishing protective layer on embedded reinforcement with Cortec’s patented, time-proven migratory corrosion inhibitor (MCI), according to Cortec’s spokesman.
“MCI-2012 IntegraPel differentiates itself from other waterproofing admixtures by directly protecting the reinforcing steel, which plays the most important role in determining the longevity of a concrete structure,” he says.
MCI-2012 IntegraPel is described as being particularly suited to protect concrete construction exposed to corrosive environments (carbonation, chlorides, and atmospheric attack).
“This product has been formulated to reduce the porosity of the concrete and make it waterproof. It also incorporates corrosion inhibitors that protect the steel rebar. These two mechanisms work to synergistically enhance the protection.”
The admixture is added to concrete prior to placement, thus inherently increasing the durability of the concrete/mortar. This cost-effective liquid is recommended for all reinforced concrete including precast, prestressed, and post-tensioned structures, he adds.
Water repellency and corrosion protection laboratory tests have been conducted on MCI-2012 IntegraPel. According to technical data obtained from a water permeability test (per Rilem Test No 11.4), the admixture provided 100 per cent improvement compared to the untreated control. The water adsorption test (per Alberta Technical Standard BT001, and BS 1881 Part 122) showed MCI-2012 IntegraPel-treated concrete absorbed 55 to 57 per cent less water compared to the control. The water-repellency tests indicated that the admixture produced a concrete of lower water permeability, decreasing the ingression of electrolytes when placed in service in harsh environments, explains the spokesman.
“The electrochemical impedance spectroscopy (EIS) data for corrosion protection indicated that the rebar in MCI-2012 IntegraPel-treated concrete exhibited 4.6 times polarisation resistance compared to the control, or 78 per cent reduction in corrosion rate,” he says.
The product does not change concrete set time and conforms to ASTM C1582 for concrete strength.
MCI-2012 IntegraPel, which does not require a special mixing procedure for its effectiveness, must be mixed thoroughly with the concrete at the batching plant prior to loading into the readymix truck drum. The admixture should be added along with the mix water, and not directly to the cement, says the spokesman, adding that it may be used with all types of Portland cements.
Providing protecting against ingress of water, chlorides, and other aggressive contaminants, it is not a vapour barrier and is non-toxic, containing no nitrites, phosphates or chromates.
The admixture forms a self-replenishing monomolecular corrosion-inhibiting layer on the steel, inhibiting the electrochemical corrosion process between metal and chloride, oxygen, and moisture in concrete. It effectively delays the onset of corrosion in new structures, reduces corrosion rates on metals as well as efflorescence, and extends the service life of structures.
Cortec recently provided another MCI solution – the MCI-2005 – to protect the structure of the Al Jalila Paediatric Care Hospital in Dubai, UAE.
“Structures in Dubai and the Gulf in general are exposed to a shallow water table with high levels of salinity. This, coupled with high temperatures and humidity levels, makes the steel reinforcement embedded in the concrete prone to rapid corrosion, threatening the structural strength and necessitating costly repair,” says the spokesman. “To counter this risk, durability-enhancing measures need to be used to ensure the desired lifespan of buildings.”
The consultant for the Al Jalila Hospital project, a development for the Dubai Health Authority, set special requirements for the durability of the concrete and the overall service life of this structure. “For this construction, they chose Cortec’s MCI-2005 to be incorporated into the mix to enhance the durability of the concrete,” he adds.
MCI-2005 is a water-based, organic, corrosion-inhibiting admixture that protects metallic reinforcement in concrete structures from corrosion induced by carbonation, chloride, and atmospheric attack. “It protects with a time-proven migratory corrosion inhibitor function. It contains a contact inhibitor that seeks out and forms a corrosion inhibiting protective layer on metals,” he explains.
The hospital was also designed to adhere to the highest international standards of quality and safety and includes sustainability initiatives. The eco-friendly design and development model of the hospital has already won international honours, including the Future Projects – Health Award at the World Architecture Festival in Barcelona, 2009; and Hospital Build Award 2011 for Best Sustainable Hospital Project.
The Al Jalila Hospital is the first hospital in the region to provide super-specialty and multi-spectrum paediatric care, catering to children from newborn up to 16 years of age. It has 200 beds and also includes a paediatric trauma centre, heart centre, transplant unit, surgical departments, outpatient clinics, dialysis unit, and oncology care. The project is the initiative of HH Sheikh Mohammed bin Rashid Al Maktoum, Vice-President and Prime Minister of the UAE, and Ruler of Dubai, as a gift to the children of the UAE and the region.
The MCI-2005 used in this project is certified by Underwriters Laboratories for NSF Standard 61 approval for use in potable water tanks, is USDA-certified Biobased (67 per cent) by BioPreferred – which earns Leed (Leadership in Energy and Environmental Design) credits to users, and meets the requirements for ASTM C1582.
US-based Cortec Corporation is the global leader in innovative, environmentally responsible VpCI (Vapour Corrosion Inhibitor) and MCI corrosion control technologies for the packaging, metalworking, construction, electronics, water treatment, oil and gas, and other industries. Headquartered in St Paul, Minnesota, Cortec manufactures over 400 products distributed worldwide.