With the SALCOS® (Salzgitter Low CO₂Steelmaking) program, Salzgitter AG is setting new standards for low CO₂ steel production. The first electric arc furnace is being built at the Salzgitter site, on the premises of Salzgitter Flachstahl GmbH, as part of the program. The flexible use of different energy sources in the electric arc furnace will reduce direct and indirect CO₂ emissions when melting down scrap steel.
PORR Special Civil Engineering is responsible for several services in this sustainable project. These include the construction of an approximately 13-metre-deep construction pit using the slurry wall method for the transshipment hall, whose 1.5-metre-thick walls and barrettes are designed for permanent use as an underground bunker. In addition, the team realized the deep foundations with 110 Megapiles (Frankipfahl NG® Ø71 cm).
Saving of several tons of CO₂ equivalent
As part of the execution planning by PORR special civil engineering, numerous optimizations in favor of sustainable construction methods were implemented in close coordination with the client and the on-site specialist planners. These include, in particular, the replacement of the underwater concrete base with a soft gel base, as well as the conversion of the planned deep foundations from 84 large-diameter piles (Ø120 cm) to 110 Megapiles (Frankipile NG® Ø71 cm). For the latter, a detailed mass balance showed significant savings in the resource-intensive building material reinforced concrete.
In particular, the 71% reduction in the volume of concrete for the Megapiles made it possible to reduce the greenhouse gas footprint by 441 t CO2 equivalent (58%). In addition, the use of low-clinker cement CEM III/B instead of a classic CEM I for the pile and slurry wall concrete contributed to further savings. Overall, these optimizations led to a reduction of approx. 2,740 t CO₂ equivalent.
The construction industry is facing the challenge of making projects sustainable. For PORR, too, sustainable action is part of its social responsibility. Worldwide efforts to reduce CO₂ and conserve resources make innovative, environmentally friendly technologies indispensable. The project in Salzgitter uses the Megapile to demonstrate an efficient pile system that conserves natural resources and significantly reduces CO₂ emissions.
