Scientists engineer stronger road material using recycled face masks
Scientists at Australia’s RMIT University are continually coming up with ways to work recovered waste items into high-performing road materials, including cigarette butts, discarded tires and building rubble. Their latest effort has a certain relevance as the world grapples with its second year of the coronavirus pandemic, with the researchers using shredded face masks in a road material they say offers some unique engineering advantages.
According to the research team, some 6.8 billion disposable face masks are being used around the world each day, generating massive amounts of waste. The scientists sought to make use of some of this waste by working it into what’s known as recycled concrete aggregate (RCA), which is made from processed building rubble and features commonly as part of the sub-grade, base, sub-base and asphalt layers that make up a road.
The team experimented with different recipes for RCA that include different concentrations of shredded surgical masks, which are made up of non-woven layers of plastic. The ideal mixture was found to be one percent shredded face mask to 99 percent RCA, which under testing was found to meet the required civil engineering standards for use as the three base layers of a road. Furthermore, the team found that the addition of the mask material improved the ductility and flexibility of the RCA blend.
“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,” says first author 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 (personal protective equipment) would also be suitable for recycling.”
The scientists say that if their new material was used to build a two-lane road stretching for one kilometer (0.6 mi), it would use around three million masks and avoid 93 tonnes of waste going to landfill. Clearly, the logistics of gathering these masks and turning them into road material presents another challenge entirely, but the team hopes its study can help inspire a shift in the way we look at the environmental consequences of the pandemic.
“We know that even if these masks are disposed of properly, they will go to landfill or they’ll be incinerated,” says Professor Jie Li, who led the research team. “The COVID-19 pandemic has not only created a global health and economic crisis but has also had dramatic effects on the environment. If we can bring circular economy thinking to this massive waste problem, we can develop the smart and sustainable solutions we need.”
The research was published in the journal Science of the Total Environment.
Source: RMIT University