KIT researchers test concrete that stores carbon dioxide
During cement production, large amounts of carbon dioxide are released. A novel concrete is intended to remove the gas from the atmosphere.
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The building materials industry is responsible for around eight percent of global carbon dioxide emissions. European researchers are developing a building material that is even intended to remove the greenhouse gas from the atmosphere.
Cement is responsible for the carbon dioxide emissions, more precisely the production of a raw material called cement clinker. "These high emissions are caused by the energy used in production, but above all also by the chemically induced deacidification of limestone in the production of Portland cement clinker, the most commonly used binder for concrete," says Frank Dehn, head of the Institute for Solid Construction and Materials Technology at the Karlsruhe Institute of Technology (KIT).
As part of the European C-SINC project, researchers from Karlsruhe are developing a clean cement substitute together with colleagues from Belgium, the Netherlands, and Spain. Cement is the binder for concrete. The project is coordinated by an industrial partner from Sweden.
Magnesium carbonate instead of cement clinker
The researchers are relying on magnesium-containing silicates, which react with carbon dioxide (COâ‚‚) to form magnesium carbonate in a targeted, accelerated mineralization process. The magnesium carbonate is then intended to partially replace the cement clinker as a secondary cementitious additive.
"By specifically separating the COâ‚‚ used from industrial exhaust gases, i.e., removing it from the atmosphere, concrete can not only become less emission-intensive in the future but also actively act as a COâ‚‚ sink," says Dehn. "The COâ‚‚ is not simply stored; it is chemically incorporated into a mineral. It remains firmly bound and thus cannot escape for very long periods."
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The goal of the project is for the clean concrete to be available as a building material in the foreseeable future. KIT is responsible for material testing: "We use machine learning strategies and structural mechanics models to investigate how the binder behaves in concrete, how we can optimally compose the concrete, and how it proves itself in practice," says Dehn. "We do this on a small scale, but also with real, large components."
(wpl)
