Greensite – Rethinking concrete sandwich structures

The “Greensite” office complex is a project that adopts a comprehensive approach to sustainability by employing a variety of sustainable building strategies. Its structure is optimized for carbon reduction, resource efficiency, and material circularity. Concrete plays a crucial role for the building’s energy performance. New options needed to be explored owing to the poor carbon footprint of cement. For the concrete sandwich structure, for example, several approaches were implemented to improve sustainability.

Together with precast producer Zuber, a component was developed whose load-bearing and facing shells were optimized in structural terms. All concretes were produced with a CEM II-c cement (with over 50 % clinker substitution). Only regionally sourced aggregates were used. The facing shell is connected and reinforced through glass fibers to prevent thermal bridging and corrosion. A cementitious foam insulation with good thermal performance characteristics ensures high durability and makes disassembly and deconstruction easy. The structural component plays a significant role in the building’s energy concept as its thermal mass can be activated passively. The sophisticated appearance of the façade materials and the structure’s robustness and flexibility allow for a long life cycle. After its end, the sandwich structure will be fully recyclable thanks to the homogeneity of the material.