On the road to clean up face masks
Researchers at RMIT University in Australia showed how disposable face masks could be recycled to make roads.
During the ongoing pandemic, disposable face masks have suddenly become one of the most littered items. But even if disposed of correctly, daily an estimated 6.8 billion disposable face masks are being used across the globe each day, generating tonnes of waste.
The researchers developed a road material made of shredded single-use face masks and processed building rubble. The material meets civil engineering safety standards. The study showed that in one kilometre of two-lane road, 3 million face masks could be used, preventing 93 tonnes of waste from going to the landfill.
Roads consist of four layers, a subgrade, base, sub-base and asphalt in top. Each layer have to be strong and flexible to withstand the pressure of heavy vehicles. Processed building rubble (also known as recycled concrete aggregate or RCA) can potentially be used on its own for the three base layers. However, the researchers found that face masks help add stiffness and strength to the material.
The optimal mixture consists of 1% shredded masks and 99% RCA, delivering on strength while maintaining good cohesion between the two materials. The mixture performs well in tests for stress, acid and water resistance, as well as strength, deformation and dynamic properties.
The study used unused surgical face masks, but other studies address the concern of hygiene. Used masks can easily be disinfected by being sprayed by an antiseptic solution and them microwaved for one minute.
The team also looked into using masks as an aggregate material in making concrete, with promising preliminary findings.