Showcasing the real science behind sustainable concrete and construction

With concrete production accounting for about 8% of the world’s CO2 emissions, major players in the industry have set their sights on substantially improving their carbon footprint — without compromising on performance.

During the recent Calcined Clays for Sustainable Concrete event held in Lausanne, Switzerland, Imerys scientists presented their peers with a scientific paper on their binder acceleration technology designed to resolve logistical problems for customers wanting to use low CO2 binders for construction.

A concept known as LC3, limestone calcined clay cement, partially replaces Portland Cement to reduce the CO2 footprint by 30-50%. LC3 is the most practical and easy way to rapidly reduce CO2 emission from the cement industry. After many years of research, LC3 is now an industrial reality with several cement plants at production. 

This new binder technology does, however, come with one drawback on performance. “When you pour concrete, you want long-term strength and a relatively quick setting time for construction to continue at the job site,” explains Hervé Fryda, Science and Technology Director for Building & Infrastructure markets at Imerys. “However, low CO2 binders are slower and might not be compatible with some construction processes.”

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Imerys’ patented calcium aluminates technology

As market leader in calcium aluminate technology, this latest Imerys innovation was specifically developed and patented to solve this challenge for customers. The accelerator, referred to as LC3+, is a mineral solution based on calcium aluminates that can be added to LC3 as a booster.

“Standard cement accelerators based on calcium or sodium salt already exist,” continues Hervé. “They work well for normal cement, and they accelerate the Portland Cement part, but they are much less efficient with LC3. As the cement part has been reduced in LC3, the contribution to early strength and the quick setting is also reduced. Our accelerator is more effective, especially at low temperatures of 5-10°C in winter when LC3 can be particularly lazy. Although production of the solution does itself emit carbon, it enables the market to produce lower CO2 cement, with a positive overall life cycle analysis impact.

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Demonstrating expertise at industry event

Four Imerys experts attended the event with the aim of raising awareness of the technology, increasing Imerys’ visibility, and learning more about what else is being developed in calcined clay technology to support other Imerys projects.

Sampling LC3+ of our Key partners has started, the ultimate plan is to ensure smooth operation in order to provide the proven solution to the construction market as a whole, on a global basis.

“Innovation is great when it translates into industrial reality and success stories. I’m convinced that our Mineral Accelerator LC3+ will be seen as an enabler of decarbonation in the cement industry, supporting the performance of new Low Carbon cements”, concludes Laurent Torres, Imerys Marketing Director of Building and Infrastructure. “The next step is to scale up our patented innovation and demonstrate value on the job site together with our industry partners."