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Face masks can be recycled into material for building roads - study

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Disposable face masks could be recycled to make material used for building roads, researchers at RMIT University in Australia have said.

The recycled face mask material would use up about 3 million masks to make just one kilometre of a two-lane road, preventing 93 tonnes of waste from going to landfill.

The new road-making material is a mix of shredded single-use face masks and processed building rubble designed to meet civil engineering safety standards.

Analysis shows the face masks help to add stiffness and strength to the final product, designed to be used for base layers of roads and pavements.

The use of personal protective equipment (PPE) has increased dramatically during the Covid-19 pandemic, with an estimated 6.8 billion disposable face masks being used across the globe each day.

“This initial study looked at the feasibility of recycling single-use face masks into roads and we were thrilled to find it not only works, but also delivers real engineering benefits,” said first author of the research paper Dr Mohammad Saberian.

“We hope this opens the door for further research, to work through ways of managing health and safety risks at scale and investigate whether other types of PPE would also be suitable for recycling.”

Roads are made of four layers: subgrade, base, sub-base and asphalt on top. All the layers must be both strong and flexible to withstand the pressures of heavy vehicles and prevent cracking.

Processed building rubble - known as recycled concrete aggregate (RCA) - can potentially be used on its own for the three base layers.

But the researchers found adding shredded face masks to RCA enhances the material while simultaneously addressing environmental challenges on two fronts: PPE disposal and construction waste.

Construction, renovation and demolition account for about half the waste produced annually worldwide, and in Australia, about 3.15 million tons of RCA is added to stockpiles each year rather than being reused.

The study identified an optimal mixture – 1 per cent shredded face masks to 99 per cent RCA - that delivers on strength while maintaining good cohesion between the two materials.

The mixture performs well when tested for stress, acid and water resistance, as well as strength, deformation and dynamic properties, meeting all the relevant civil engineering specifications.

While the experimental study was conducted with a small amount of unused surgical face masks, other research has investigated effective methods for disinfecting and sterilising used masks.

In December, a five-year University of British Columbia study concluded that recycled concrete can perform as well as, or better than, conventional concrete.

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