First certified GWP Level 4 concrete in use in Berlin, with a 60% reduction in carbon footprint

Amid urban development, Siemensstadt Square stands as a symbol of innovation and progress. Siemens and its IPA partners are working intensively to incorporate CO2-saving design principles and utilize optimized products. A shared commitment, a collaborative process, and innovative partners are key to this effort.

A milestone in terms of the building materials used is the first-ever use of certified Level 4 concrete in the Berlin area. The Environmental Product Declaration (EPD) from EPD Norge confirms an impressively low total GWP of 97.1 kg/m³. This has also been independently verified to represent a 60 percent reduction in CO₂ content compared to industry benchmarks—a significant step toward more climate-friendly concrete construction.

Focus on Building Materials

For the concrete pouring of the floor slabs, HOCHTIEF Infrastructure Building Berlin commissioned SCHWENK Beton Berlin-Brandenburg to supply the concrete and the SCHWENK Technology Center to develop the concrete mix.

Typically, CEM III/A 32.5 N-LH (na) concrete from the SCHWENK plant in Bernburg is used for floor slabs, which already meets the CSC-CO2 Level 3 standard. However, this innovative construction project required an even more efficient concrete: a certified Level 4 concrete.

Development of a new concrete for maximum CO₂ reduction

To achieve this ambitious goal, the SCHWENK Technology Center developed a completely new mix design based on CEM III/B 42.5 L-LH/SR (na) with a total GWP of 218 kg/t, supplied by the Bernburg plant.

Thanks to the excellent performance of this cement, the concrete mix design was further optimized through extensive preliminary testing in Bernburg. The low clinker content—just 19% per ton of cement—posed a particular challenge, as all admixtures derive their reactivity from the cement clinker.

By combining CEM III/B with an optimized mix, CSC-CO₂ Level 4 was ultimately achieved—without compromising on durability and longevity.