Present-day construction is all about reducing materials and grey energy. However, concrete is still the go-to material in construction, in particular for residential buildings. Concrete contains cement, the production of which requires high temperatures, which releases a significant amount of greenhouse gases. A new construction system developed at the ZHAW School of Architecture, Design and Civil Engineering in cooperation with ETH Zurich and industry partners could provide an alternative.

The so-called “Stahlkammer” (steel chamber) system uses hybrid structures composed of four-millimetre-thick steel frames filled with clay and other materials. This cement-free alternative reduces CO2 emissions by 90 percent compared to conventional concrete. Unlike unprotected steel structures, the system is also highly fire-resistant and thus meets fire safety requirements. The combination of these two materials manages to make optimal use of both materials while eclipsing their negative properties.

Promoting the circular economy

The construction system is relatively inexpensive and suitable for residential buildings of up to five storeys. Flexible structures make it possible to redesign buildings or make them more compact or taller, according to Jay Renée Thalmann, who led the project at the Institute for Building Technology and Process. “Building parts can be disassembled and reused, which is in line with the principles of the circular economy.”