Given the current focus on the environment and reducing greenhouse gas emissions, US-based Cortec says its MCI Technology offers a simple but powerful strategy to help the construction industry take a pivotal step towards a smaller carbon footprint.
MCI Technology is said to have the ability to enhance the durability of concrete. Ashraf Hasania, Cortec’s MCI Technical Sales and Product Manager, who holds degrees in civil and environmental engineering, explains: “Increasing the service life of concrete structures using durable materials can reduce the need for demolishing old structures and building new ones. It can also lead to less need for major repairs. This lowers the carbon footprint of concrete structures and promotes sustainable practices.”
Concrete is the world’s most widely used construction material – and also one of its greatest contributors to greenhouse gas emissions. The root cause is cement production, which alone accounts for approximately eight per cent of global CO2 emissions, says Cortec.
The way MCI helps concrete structures last longer is by attacking one of the biggest enemies to concrete durability: corrosion of the metal reinforcement.
“As rebar rusts due to carbonation, chloride exposure and other environmental conditions, it expands and puts pressure on the concrete cover. This leads to cracking, spalling, and a vicious cycle of further exposure to corrosives and additional damage. Based on salts of amine carboxylates, MCI Technology interrupts this process by migrating through the concrete pores to form a protective molecular layer on the rebar surface to delay and reduce corrosion. Service life models and lab and field studies have shown that MCI can increase service life by three to four times. This translates into a comparable reduction in concrete’s carbon footprint,” Hasania says.
MCI can be used at any stage in a structure’s lifecycle, but the best course to pursue is early treatment.
“Sustainability in construction starts early in the process,” Hasania advises, “specifically in the design phase with careful selection of construction materials and concrete mixes.”
Ideally, this should include the choice of MCI concrete admixtures, which can be added to new concrete at the readymix plant or construction site. In contrast to calcium nitrite admixtures, MCI admixtures have a low dose independent of chloride loading and do not negatively affect concrete mix properties, he points out.
Existing structures can be treated with MCI in the form of surface-applied corrosion inhibitors (with or without water repellant) and repair mortars. Once applied, the MCI molecules migrate through concrete pores to protect embedded rebar in sound concrete, or to even out corrosion potential and interrupt the problematic ring-anode/halo effect between new patch repairs and old concrete, he adds.
Other sustainability features
In addition to the main goal of helping concrete structures last longer, MCI Technology is said to offer other attractive features. For example, MCI-2005 is a USDA-certified biobased product that contains 67 per cent USDA-certified biobased content. This use of renewable resources can help the project earn credits toward LEED (Leadership in Energy and Environmental Design) certification while adding a more sustainable image to the structure and builder. Another attractive feature is the low toxicity of MCI products, many of which are certified to meet NSF Standard 61 for use in potable water structures, Hasania says.
“Considering the costs of construction and rebuilding alone, the benefits of extending concrete service life are clear. Add to it the ripple effect of decreasing the amount of new cement needed to repair and replace old structures, and the advantages of MCI Technology go even further – helping the construction industry take major steps toward a smaller carbon footprint and a more sustainable future,” he concludes.
Cortec Corporation is the global leader in innovative, environmentally responsible VpCI and MCI corrosion control technologies for packaging, metalworking, construction, electronics, water treatment, oil and gas, and other industries. Headquartered in St Paul, Minnesota, Cortec manufactures over 400 products that are distributed worldwide.