Turning excavated materials into building materials

Researchers in Switzerland are making the case for using earth as a building material. And not just any earth, but specifically material excavated from construction sites. This would save both resources and energy.

During construction, excavated material is normally transported away in a truck and tonnes of sand, gravel and cement are delivered in its place. In the future, this excavation material – the inorganic part of the soil – should be used as a building material. This is the aim of researchers at the Federal Institute of Technology (ETH) in Zurich.

Earthen construction is actually one of the oldest building techniques in the world, but it is hardly used now, particularly in modern cities. If greater use were made of the excavation material in construction, it would short-circuit this supply chain, spare sand and gravel resources and save energy and CO2.

There are other benefits: using earth as plaster can also help naturally regulate air humidity and make for a significantly more comfortable indoor climate, writes ETH Zurich. And it is not just suitable as a replacement for structural building materials like concrete – it should in fact be seen as an alternative for building services technology.

ETH researchers are now working to revolutionize old building techniques to ensure that earth can be used for building in the modern world. Their colleagues at the Federal Laboratories for Materials Science and Technology (Empa) are developing mud plasters with aerogels to further improve the humidity-regulating properties of earth. And at ETH Zurich itself, researchers are working on a liquid earth that can be poured into formworks in the same way as conventional concrete.

An exhibition opens on 30 October at ETH Zurich that will show the potential of excavation material in construction.


Image credit: Terinea IT Support via Flickr

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