Displaying items by tag: carbon sink

US: A team from the Massachusetts Institute of Technology (MIT) has developed a new method to sequester CO₂ in concrete before curing it. The method is based on the addition of bicarbonate of soda, which reacts with cement to produce a calcium carbonate-calcium silicone hydrate composite. The Journal of Engineering has reported that the method adds the benefits of CO₂ mineralisation during production and casting, doubling the mechanical performance of early-stage concrete. It also eliminates the effects of carbonation reactions in cured concrete, which weaken the concrete by lowering its alkalinity, which accelerates the corrosion of rebar. The method has the potential to sequester 15% of CO₂ emissions from cement production.

The team said “The pre-curing capacity of concrete to sequester CO₂ has been largely underestimated and underutilised. Our new discovery could further be combined with other recent innovations in the development of lower carbon footprint concrete admixtures to provide much greener, and even carbon-negative, construction materials.”

Belgium: The EU Innovation Fund has awarded Euro4.5m to a consortium consisting of Prefer, gas provider Fluxys Belgium, lime producer Lhoist and carbonation technology developer Orbix. The collaborators are working on a project called CO2ncrEAT. The project will carbonate steel sector by-products with captured CO₂ from Lhoist's Hermalle lime plant to produce alternative building materials. CO2ncrEAT will be the first project to employ Orbix's innovative technique for the purpose. Fluxys Belgium's pipeline technology will convey the Hermalle plant's emissions over a distance of 2km to a Prefer concrete blocks plant.

The consortium said that it will use 12,000t/yr of CO₂ to produce 100,000t/yr of reduced-CO₂ concrete blocks. The use of alternative raw materials in the blocks will further reduce their carbon footprint by 8000t/yr.

Prefer managing director Raphaël Grimont said “As market leader, we must ensure the sustainability of our business by offering innovative and eco-friendly products to our customers. With the CO2ncrEAT project, our building materials will be produced through a sustainable and efficient process and based on local, circular raw materials. The Prefer masonry block of tomorrow will retain all the advantages of the traditional block, with the difference that it will benefit from a negative carbon footprint. We are proud to develop this exceptional project together with key industrial partners, while benefitting from the trust of the European, Belgian and Walloon authorities.”

UK: Denmark-based architecture fund Henrik Frode Obel Foundation has named Seratech as winner of its Obel Award 2022. The award recognises architectural contributions to global development. Seratech has developed an olivine-based composite cement produced using CO₂ from flue emissions, which can sequester double the CO₂ of ordinary Portland cement (OPC). When used as 40% of a blend with OPC, it is able to completely offset the emissions of concrete production.

Team member Barnaby Shanks said "The beauty of the idea is that you can just use it as normal concrete. There are other carbon-neutral materials, but they can be limiting because they can only be precast, cured in a lab in special conditions and shipped elsewhere. We want people to retain the freedom to use concrete the way that they are used to. We don’t want to limit people in any way because we’ll just lessen the amount of impact we can have."

Germany: The Ministry for Economy and Climate Protection has presented HeidelbergCement with its German Climate and Environment Innovation Prize (IKU) for its ReConcrete-360° concrete recycling process. The process retrieves hardened cement paste from waste demolition concrete for use in place of limestone in clinker and cement production. The recycled material can also bind CO₂ to act as a carbon sink.

Global research and development Wolfgang Dienemann said “With ReConcrete-360°, we have succeeded in developing a limestone substitute from demolished concrete that also allows us to use the carbon-containing exhaust gases from cement production. A small revolution with a big impact: In Germany alone, the CO₂ savings potential of this process is 10Mt/yr. The IKU award underlines that we can be proud of our pioneering innovation.”