PORTLAND, Ore. (KOIN) – Single-use masks have been a necessity during the pandemic, not just for healthcare workers, but for everyone. In the last two years, those masks have filled trash bins around the world. Now, researchers at Washington State University say they might have a way to reuse them. 

A WSU research team published a paper in the journal, Materials Letters, stating that a concrete mixture made with mask materials was 47% stronger than commonly used cement after a month of curing. 

Xianming Shi, a professor and interim chair of the Department of Civil and Environmental Engineering and the corresponding author on the paper, said he’s always looking at “waste streams,” or the lifecycle of garbage humans produce. 

He said he often asks himself, “‘How do I turn that into something usable in concrete or asphalt?’” 

Microfibers are already sometimes added to cement concrete to strengthen it, but WSU said they’re expensive. Adding microfibers to reinforce concrete can potentially reduce the amount of cement needed for a project, or make the concrete last longer. By using materials like this, builders and owners could save money and reduce carbon emissions. 

Single-use masks are made of polypropylene or polyester fabric where they contact the skin and an ultra-fine polypropylene fiber for the filtering layers. This fibrous material can be useful for the concrete industry, the WSU paper argues. 

“If they are not reused, disposable masks can remain in the environment for decades and pose a risk for the ecosystem,” WSU wrote in a press release about the paper. 

Shi said the research team’s work showcases one way to divert used masks from the waste stream to a high-value application. 

To prove their concept, researchers took pieces of mask fibers ranging from 5 to 30 millimeters in length and added them to cement concrete to strengthen it and prevent it from cracking. They removed any metal pieces and cotton ear loops before cutting them up and mixing them in Portland cement, the most common type of cement used around the world. 

Researchers say the fibers mixed in the concrete prevent microscopic cracks from growing to wider cracks, which can eventually cause concrete cement to fail. 

WSU said the team is conducting more studies to test their idea that graphene oxide-treated microfibers could protect concrete from frost damage and from deicing chemicals that are used on roadways. They would also like to apply this technology to the recycling of other polymer materials, such as discarded clothing, to incentivize collecting more of these waste materials.