About 3 million single-use face masks could be used to build the base of a one-kilometre, two-lane road, according to research by engineers at Australia’s RMIT University that explored a way to turn discarded masks and construction waste into road-building material.The researchers shredded single-use face masks and combined them with processed building rubble, known as recycled concrete aggregate (RCA). Tests showed that the resulting material met relevant civil engineering specifications for use in road base and sub-base layers.The study, titled “Repurposing of COVID-19 single-use face masks for pavements base/subbase,” published in Science of the Total Environment, found that using the material for one kilometre of a two-lane road could consume about 3 million masks while keeping 93 tonnes of waste out of landfill.The research was carried out in 2021, when the widespread use of disposable masks during the Covid-19 pandemic had created another stream of waste alongside the huge volumes of construction and demolition material generated worldwide.
How the mask-and-rubble mixture works
A road typically consists of four layers: subgrade, sub-base, base and the asphalt surface. The lower layers need to withstand the pressure from heavy vehicles while retaining sufficient flexibility to minimise cracking.RCA, produced from processed building rubble, can potentially be used in these layers. The RMIT researchers found that adding shredded face masks could improve the material’s stiffness and strength while also providing a way to reuse two different waste streams.The researchers identified a mixture containing 1% shredded face masks and 99% RCA as the optimum combination in their study.The material was tested for properties including strength, deformation, stress, acid and water resistance and dynamic performance. It met the relevant civil engineering requirements in the tests, suggesting the mixture could have potential as a road-base material.The study described its work as the first investigation into the potential use of disposable surgical face masks in civil construction.
A waste problem on two fronts
The research was driven partly by the enormous increase in personal protective equipment use during the pandemic. The study estimated that about 6.8 billion disposable face masks were being used around the world every day.At the same time, construction, renovation and demolition activities account for about half of the waste generated each year globally.In Australia, around 3.15 million tonnes of recycled concrete aggregate was being added to stockpiles annually rather than reused, according to the study.The researchers therefore looked at whether one waste material could help improve another recycled material while keeping both out of landfill.Dr Mohammad Saberian, the study’s first author, said the findings showed that recycling single-use masks into roads was technically feasible and could provide engineering benefits.“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,” Saberian said.He said further work was needed to address health and safety issues involved in handling used PPE on a larger scale and to determine whether other forms of protective equipment could also be recycled in construction.
What about used masks?
The RMIT experiment used a small quantity of unused surgical masks. That distinction is important because the researchers were testing the engineering properties of the material rather than demonstrating a large-scale system for collecting and processing contaminated PPE.The study noted that other research had examined methods for disinfecting and sterilising used masks, including techniques capable of killing viruses. However, the RMIT work said further research would be needed to address the health and safety risks of recycling used PPE at scale.The researchers had also explored another possible application for shredded disposable masks, using them as an aggregate in concrete. Those preliminary findings were described as promising.Professor Jie Li, who leads the RMIT School of Engineering research team, said the idea emerged after researchers saw discarded masks littering local streets.The approach reflects a broader circular-economy concept: rather than treating discarded masks and construction rubble solely as waste, both materials could potentially become inputs for new construction products.For now, however, the road study remains an experimental demonstration of feasibility rather than evidence that mask-based road materials are ready for widespread use.