Disposable masks have protected millions of people from the COVID-19 pandemic. Once used, they are often dumped in trash cans or left on sidewalks. But soon these masks could have a new purpose in road construction. Ashlyn DeLoughy has the details.

Professors and students in the Department of Construction Management at Eastern Carolina University investigated the possibility of using polymer fibers from recycled masks in hot mix asphalt used to pave roads. They have been working with ST Wooten and the North Carolina Department of Transportation on this project since February.

The hope is that using these fibers will help asphalt resist rutting, which is the permanent deformation of the pavement that can occur due to traffic volume, tire pressure, load axial and vehicles traveling on the same areas on the roads above and again.

Dr. George Wang, a professor at ECU and head of the construction management department, is currently leading this project.

“We noticed many face masks being used every day. This represents approximately six to seven billion masks worldwide, which are single-use masks, which represents enormous pollution. But these face masks are a type of plastic.

Wang is conducting this research alongside Associate Professor Dr. Carola Massarra, Assistant Teaching Professor Dr. Jodi Farrington, Teacher Chelsea Buckhalter, and graduate student Md. Hasibul Hasan Rahat.

“I spoke to my team because it’s only been the last one or two years that plastic pollution, globally, has come to the attention of government, environmental news and also researchers. So that’s going to be a very important area for us, you know, to put the effort into doing research.

The team began their research process by shredding the face masks. In March, they ran various lab tests, and in early April, they were adding the shredded mask material to the hot mix asphalt at 0.25% to 1.5% of the total weight. With paving done at high temperatures reaching up to 300 degrees, the plastic in the masks becomes fluid and acts as a binder that hardens as it cools. This increase in polymer fiber content in the hot asphalt mix creates strength and helps reduce rutting.

But if commercialized, this asphalt mix would do more than just decrease rutting. According to Wang, it would also reduce pavement costs, decrease the amount of energy used in the pavement production process, and decrease environmental pollution.

“This has been a very important area for some time. The federal government has a goal, I think by 2050 we have to reduce plastic pollution to a very low percentage. Currently, we have 91% of plastic in landfills or in rivers, lakes and beaches. This research is therefore very important.

Preliminary results from the North Carolina Department of Transportation appear positive so far, with the asphalt mix sample exhibiting “excellent to very good resistance to permanent deformation” according to an ECU press release.

The state allows a maximum rut depth of 11.5 millimeters for local roads and 4.5 millimeters for interstate highways. Tests of various blends with the recycled masks show a rut depth range of 0.9 to 3.2 millimeters. The addition of polymer fibers from recycled masks allows the mixture to be used as a “premium road surface”.

According to Wang, if commercialized, this asphalt mix could revolutionize the future of paving.

“Normally every 15 to 20 years you have to spend money in the government budget to repair roads because of deterioration, cracks or rotting. So if the design life is extended to 25 or 30 years, the construction costs on the federal government budget can be saved to do something else.We are still running out of budget for infrastructure construction.

A technical document describing this research is currently under review. Wang’s next step is to prepare a proposal for the Ministry of Energy.

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