Rising from the rubble: how to turn construction waste into the building blocks of the future

For centuries builders and craftsmen have been reusing materials, whether it be wood, bricks or tiles.

But now researchers in Spain and Italy are taking things a step further - developing a range of new materials from waste that would once have ended up in landfill.

The researchers at the European-backed project RE4 hope that one day they’ll be able to create entire buildings made from recycled materials, including pre-fabricated panels that can be unbolted and reused elsewhere.

At a test site in Spain, experts are comparing a recycled building with a traditional building and will be monitoring them both over a four-month period to see how they stand up.

Felipe Mata Gutiérrez, technical manager at Acciona, a Spanish infrastructure and renewable energy company, says they’ll be looking at energy efficiency in particular.

They’ll also be comparing the time it takes to build and dismantle each structure.

"What we can do is a comparison at a thermal level and at a construction level,” says Gutiérrez. “With that, we can do a comparison in terms of energy efficiency and we can also measure the time it takes to build and then demolish each one of them."

THE FUTURE

If the results are promising, the researchers will argue for a change in building regulations to allow for far greater use of recycled materials in new offices and homes.

Project Manager María Casado says recycled aggregates have been used to manufacture all the components and materials used in the test building.

But it’s not as easy as it sounds.

The nature of demolition means that a wide variety of materials – such as gravel, plaster, stone and asphalt – end up mixed together and need to be properly sorted before they can be reused.

“The main problem is to separate and classify it, because the construction and demolition waste is all mixed up together,” Casado says.

With that in mind, researchers at the Italian engineering company, STAM, are looking at ways to tackle the problem.

Their new system uses a multispectral camera and artificial intelligence to identify different materials, and a robot arm to separate them.

Senior Robotic Engineer Mony Khosravi said the plan is to deploy this kind of system onto building sites to separate waste for recycling.

But the engineers admit their prototype isn't yet robust enough to cope with real-world conditions.

Area Manager Umberto Battista said: "Obviously there are inevitable problems of dust, infiltrations due to rain, wind and atmospheric events in general, and for large volumes of material it is also necessary to use more robots than the single robot we are using in our laboratory."

Nevertheless, the researchers believe their goal is within reach. And one day whole cities could even be recycled.

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