According to Washington State University (WSU) press release explained researchers used disposable masks to increase the strength of concrete by up to 47%.
As the coronavirus pandemic continues, the use of disposable masks is also increasing, which is often dumped in public places as well as in our oceans. According to a study last year, mask contamination increased by a whopping 9000% as countries made it mandatory to wear masks to prevent the spread of the virus. However, the billions of masks produced during this period have become a major issue for waste management.
What are disposable masks made of?
Disposable surgical masks can be made of polyester fabric or polystyrene, polyethylene or polypropylene, or a thermoplastic polymer that can be molded into any shape while working at high temperatures. Many filters used in N95 masks also use polypropylene and, if left untreated, can remain in the environment for decades. In addition to the polymer, the mask includes a metal clip and a cotton ring. These rings are recyclable, but are eventually dumped in the untreated garbage heap.
However, used masks can be valuable commodities if handled properly, as Xianming Shi, professor of Department of civil and environmental engineering at WSU, successfully discovered when experimenting and discovering the use of masks in concrete.
This can be very beneficial for our environment, as our regular readers are well aware that concrete production is a carbon-intensive activity and responsible for about 8% of global emissions.
Other carbon reduction experiments have shown that adding microfiber increases the strength of the cement, reducing the need for a project and minimizing emissions as much as possible. However, it may not be widely used as it is an expensive material to construct microfibers.
Adding disposable masks to the mix
As an alternative, Professor Shi and his team have turned to disposable face masks and developed a process to create microfibers for use in concrete production. By cutting the mask into pieces 5-30 mm long and treating it with graphene oxide before mixing it into the cement paste, the researchers were managed to absorb or dissipate the fracture energy that would normally lead to the formation of small cracks in concrete.
Graphene oxide allows the microfiber to adhere strongly to the surface without This can result in small cracks which could turn into large gaps that can eventually turn into material failure.
Researchers have also repurposed the face mask’s cotton rings and metal clips by grinding them and adding them to ordinary Portland cement, basic ingredient for any concrete, grout or mortar products.
Their proof-of-concept study found that concrete made with the masking material was 47% stronger after curing for a month. The team is currently working to ensure that the concrete is protected from frost damage and the continued use of road deicing agents. In the future, this method could be applied to use other polymers like discarded clothing, which would serve as incentive to collection of this waste.
The findings of the study were published in Materials Letters.