Reusable formwork system reduces concrete in floors

The Block Research Group based at ETH Zurich University has developed a reusable and lightweight formwork system.

The Unfold Form system makes concrete floors using 90% less steel and 60% less concrete compared to standard reinforced concrete flooring. This reduces construction carbon emissions with less material waste, making the system more environmentally friendly

The Unfold Form system uses lightweight plates that are connected with textile hinges. When transported, the plates are then folded flat, before being unfolded at the construction site into a shape similar to a fan, entirely self supported. This unfolded shape is capable of supporting 1,000 kg of concrete. The strength of this formwork is derived from its curved shape.

The self-supporting shape has corrugated ridges that prevent bending. The weight of the concrete is distributed evenly so that no areas are in danger of collapsing.

The reusable framework system can be assembled on-site in half an hour. In tests, the flat-pack formwork weighing 24 kilos was transported by plane from Switzerland to South Africa as passenger luggage.

The system has been used to make concrete flooring 3 metres by 1.8 meters with concrete weighing 1,000 kilos, ranging in thickness from 5 centimetres to 13 centimetres.

The DTH team, Lotte Scheder-Bieschin, Dr. Tom Van Mele, Mark Hellrich and Dr. Philippe Block, used computer-aided design to create the unique shape of the lightweight formwork system. The team is partnering with NonCrete to more widely use the Unfold Form system. They are also developing the use of bio-based concrete with the system.