Disposable face masks used to prevent the spread of Covid-19 could be recycled to make roads, a new study suggests.
Researchers at RMIT said they had developed a road-making material by combining shredded single-use masks and processed building rubble.
They said it would both meet civil engineering safety standards and help tackle the vast amount of waste generated from Covid protective equipment.
The study, published in the journal Science of the Total Environment, found using the material to make 1km of two-lane road would use about 3m masks and prevent 93 tonnes of waste going to landfill.
The lead author, Dr Mohammad Saberian, said the researchers found the blend of recycled concrete aggregate and face masks could make “a stronger, better and more flexible road”.
“The pandemic has created too much rubbish,” he said. “We saw the masks in parks and streets in every suburb. We were inspired by the idea to look at circular economy solutions and reduce the pandemic-generated waste.”
Saberian said the masks delivered engineering benefits when used in construction.
“We need to have flexible roads, otherwise the road structure wouldn’t be able to sustain the wheel loads. [Recycled] masks or plastic can provide such a good flexibility property,” he said.
However, other experts in the field raised concerns about whether “downcycling” masks into road base was the best strategy.
Sami Kara, a professor of sustainable manufacturing at the University of New South Wales School of Mechanical and Manufacturing Engineering, said recycling should be a closed loop in.
“It should ideally replace the virgin source one to one,” he said.
“Here we’re talking about cascading use. The demand for face masks continues going up and we create another demand that wasn’t there before. This is rebound effect.
“We shouldn’t confuse waste management with what is sustainable.”
Kara said the composition of the mask, and what happens to it during its lifecycle, needed to be examined as it could lead to its own environmental problems, such as microplastic pollution.
Separate research has found masks were a potential source of harmful microplastic fibres, which cause problems when they mix into land and waterways.
Dr Mayuri Wijayasundara, a lecturer in engineering management at Deakin University whose research focuses on the circular economy, said the solution to waste management presented in the study was “sub-optimal”.
Using the plastic as part of a building filler did not recover the highest value of the material, she said.
“Thinking of design at an earlier stage is the ideal solution,” she said. “If something is single use, you need to ideally make them compostable or design the mask for reuse.”
Waste created by personal protective equipment (PPE) has increased dramatically during the Covid-19 pandemic, with much ending up as ocean pollution. An estimated 6.8bn disposable masks are used across the globe daily.
“Even through Covid we need to focus on the core problems we need to address and have that long-term thinking,” she said.