Building with sawdust and seaweed

New ‘wood’ from sawdust

In the laboratories at DTU, the researchers have been running experiments with different ingredients for several years—initially with funding from the Independent Research Fund Denmark and now from the EU.

By adjusting different parameters in the production process, they have produced promising materials in collaboration with partners at the Royal Danish Academy among others—and this has got the Associate Professor excited:

“It would be brilliant if for example sawmills could cut out strong load-bearing beams, but we then take all the sawdust and use it to make materials that do not need to be as strong. It turns out that in some regards, we are quite close to what you get from actual wood. Now we want to find out if we can find ways to push the properties of the composite material so we can optimize it.”

The work also focuses on reducing the amount of waste generated in the production process by e.g., feeding by-product or obsolete products back into the production chain.

“In some of the systems we've looked at, we were able to recycle the ‘waste’ up to five times before it starts to affect the quality of the material we produce,” Anders Egede Daugaard says.

Difficult and valuable

Because the newly developed biopolymers—unlike traditional oil-based polymers—react with water, the new building materials will, to varying degrees, be vulnerable if exposed to moisture. This may place limits on where in a new building they can be used, and it may necessitate a protective layer of e.g. paint.

“At the same time the water sensitivity will allow us to place discarded materials into water and get us back to the start, where we can put them back into the production process. This is a valuable characteristic—but of course only if we ensure that the materials are used in parts of a building where they don’t get wet,” the Associate Professor stresses.

Some of the end-of-life building materials may also be able to simply be composted—unlike many traditional materials such as concrete and insulation that are sent to landfill.

Timeline

So, when can we expect to see the new materials in use on construction sites? It depends on the level of ambition, Anders Egede Daugaard explains:

“We know several companies that work with simple products with no requirements for strength and durability or as replacements for plastic, and they could technically start using our solutions right away. But if we're aiming to make load-bearing structures, it will take longer.”

The projects the DTU researchers are working on also involve machine learning experts who will use their skills to hopefully speed up the development process.

“With their help, we will investigate whether we can design these materials in a faster way where, by feeding an artificial intelligence with the knowledge we have, we can expand our knowledge so that we can use it in the further design process,” the Associate Professor says.

Development of new standards and revision of existing legislation will likely also be necessary before such new materials can be used by the construction industry.

Ultimately, the dream is to create a local production unit which allows custom printing or construction of elements as needed on site.