“An ingenious approach to casting concrete surfaces of highly complex geometrical definition” – Holcim Awards Innovation Prize Jury

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    High-efficiency concrete formwork technology, Zurich, Switzerland Final result: two-sided free-form (double curved) concrete cast with corresponding wax formwork.

The jury commended the project for its excellent level of research and practice-oriented experimentation. The proposed concrete production process developed by a research team in Architecture & Digital Fabrication at the Swiss Federal Institute of Technology (ETH Zurich) is an ingenious approach to casting concrete surfaces of highly complex geometrical definition. It advances an entirely new sequence of production phases. First, a robot arranges a pile of sand within formwork into a shape that corresponds to the lower profile of the desired geometrical form to be cast.

Last updated: August 30, 2012 Zurich, Switzerland

Then, liquid wax is poured over the “dune shape” of the sand. Once cooled, the wax negative form becomes one element of the actual formwork, finally into which concrete is poured to produce the desired element. After the process is completed, the wax negative form can be heated and made liquid, in order to be reused for the next casting process. The same obviously applies to the sand used to create the wax negative.

The outstanding merits of this innovative concrete production method are fourfold: First, it eliminates the need to use expensive and marginally-recyclable construction materials such as wood and steel sheet, while replacing the traditional materials for concrete formwork by wax. At the same time, it reduces formwork-related construction waste almost to zero. Second, it considerably cuts down the tremendous volume of manual labor necessary to produce highly complex concrete formwork because robots take-over the majority of the workload. Third, the relatively low cost of this formwork technology is a prerequisite for the economical production of geometrically complex precast concrete elements in small series. Fourth, there are virtually no limits regarding the three-dimensional shape of precast concrete elements with a hitherto unimaginable degree of accuracy.

Overall, this visionary formwork technology for geometrically complex concrete elements is a real quantum leap combining the utmost computer-aided manufacture (CAM) technologies with the latest generation of robots that has the potential for revolutionizing the construction process enhancing sustainable construction.