Buy recycled concrete as CO2 storage – salzburg.ORF.at
Environment&Climate
The production of concrete releases more climate-damaging carbon dioxide (CO2) worldwide than international air travel. Therefore, Salzburg and Swiss researchers in Golling (Tennengau) are now enriching recycled concrete with the greenhouse gas and building a residential complex with it.
The building material is responsible for seven percent of carbon dioxide emissions worldwide, significantly more than international air traffic. The process of binding the greenhouse gas in concrete has already been set up in Switzerland and some of it has been publicly advertised there, says Roland Wernik, Managing Director of Salzburg Housing.
Granules from old concrete bind carbon dioxide
Demolition concrete is first crushed into granules and then mixed with CO2, explains recycling entrepreneur Christian Ehrensberger. “The concrete binds the carbon dioxide in the fine pores of its substance surface. The refined concrete granulate is fed into the production chain for fresh concrete, where it replaces sand and gravel.”
Wernik adds that this means ten percent less CO2 emissions in the climate balance of fresh concrete. The research project is being carried out in Werfen-Tenneck (Pongau) in cooperation with Salzburg Wohnbau, the companies Deisl-Beton in Hallein (Tennengau), the Ehrensberger gravel and recycling plant in Tenneck as well as the Structural Testing and Research Institute Salzburg (bvfs) and a Swiss Company.
Ten kilos of CO2 bound per cubic meter of concrete
Currently, ten kilograms of CO2 can be bound per cubic meter of concrete, and this amount is now to be multiplied. In the future, it should also be possible to bind carbon dioxide in rock or humus. In Tenneck, up to 120 tons of recycled concrete are to be enriched with CO2 every day. The carbon dioxide required for this is delivered from a bioethanol plant in Tulln (Lower Austria) and liquefied for transport.
“We expect to be able to bind 6,000 to 8,000 tons of CO2. This also makes the whole thing interesting for the trading of CO2 certificates and shows that negative emissions can not only bring costs, but can even bring economic success,” says Wernik.
Climate protection as a lucrative business model
“Climate protection must be a line of business where money is earned with generated climate benefits,” says the managing director of Neustark AG, based in Bern (Switzerland). Recycled concrete has also already been used for schools in Anif and Wals-Siezenheim (both in Flachgau).
The building material, which has now been mixed with carbon dioxide, is now being used for the first time in a residential complex in Golling. The aim of the Salzburg-Swiss research is now to use the process in this country for public construction contracts.