On the former U.S. Army Campbell site in Heidelberg, Germany, a remarkable new residential construction concept is currently taking shape: the ‘Dreihaus’ project is a fully conceptualised, 3D-printing-optimised, scalable building con- cept that uses CO2-reduced construction materials. For the first Dreihaus reference buildings, Heidelberg Materials is supplying advanced high-tech materials with significantly reduced CO2 emissions.