Reviving ancient concrete-construction methods

A Swiss consortium has revived ancient techniques to make unreinforced concrete.

A new type of non-reinforced concrete using stone offcuts has been made by a Swiss-based consortium.

Academics at EPFL, ETH Zurich, and a Geneva-based architecture firm claim their method reduces cabon-intensive, cement-based binders.

They developed the technique after studying historical archives from Roman times to the 19th Century, mostly from France and Germany, to find forgotten construction processes and test various options using different cement mixtures and processes.

The team built six load-bearing walls using the recovered stone-quarry waste and fieldstone.

The prototypes were divided into two groups to test two different construction methods and three types of mortar-based binders.

The first method involved placing the mortar in the formwork before adding stones, while in the second the stones were laid first and then coated with mortar.

Of the three binders, one had a small quantity of cement, another was lime-based, and the third made from infertile soil.

Due to the size of the stones, the team named the method Cyclopean to reference a type of stonework in early architecture.

The project is part of the Circular Building Industry Booster, a programme backing innovative construction-industry initiatives based on circular principles.