MELBOURNE – In a potential solution to pandemic-generated waste, researchers at RMIT University in Australia have developed a new road-making material from shredded single-use face masks and processed building rubble
Analysis shows the face masks help to add stiffness and strength to the material, which is designed to be used for the base layers of roads and pavements and meets civil engineering safety standards.
It is well known that 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.
“Multidisciplinary and collaborative approaches are now needed to tackle the environmental impact of Covid-19, particularly the risks associated with the disposal of used PPE and our initial study looked at the feasibility of recycling single-use face masks into roads,” said RMIT’s Dr Mohammad Saberian. “We were thrilled to find it not only works, but also delivers real engineering benefits and we hope this opens the door for further research.”
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, namely 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% shredded face masks to 99% 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.
A comprehensive review of disinfection technologies found that 99.9% of viruses could be killed with a simple “microwave method”, where masks are sprayed with an antiseptic solution then microwaved for one minute.