solution to the waste problem
Study: Old corona masks make concrete more stable
Concrete with recycled corona scrap. The plastic in the protective equipment can apparently make concrete much more resistant.
© RMIT University
Millions of tons of protective equipment have been produced and used since the start of the corona pandemic. The question now arises: what to do with all the Corona scrap? A study from the US could now offer a solution.
The corona pandemic is not over yet, but the fight against and protection against the virus has already produced unimaginable amounts of waste. According to a study by Princeton University, approximately 130 billion face masks were used per month worldwide in 2021 alone. There is also equipment such as protective suits, rubber gloves and, last but not least, numerous Covid-19 tests.
Study: Corona scrap makes concrete more stable
So where does all the plastic waste go? Researchers at the Royal Melbourne Institute of Technology in Australia could now provide part of the answer. It was clear to them very early on that the world would have to deal with the enormous mountain of waste after the corona pandemic at the latest. That is why in 2020 they started research into the recycling of protective equipment and masks.
“We urgently need intelligent solutions to the ever-growing pile of Covid-19 waste. A challenge that will persist after the pandemic ends,” explains the study’s lead author Shannon Kilmartin-Lynch, as reported by the journal. scinexx”. .
One approach proved particularly promising: recycled and shredded protective equipment was mixed with concrete. What seems absurd at first glance is scientifically clear. Masks, jackets and other equipment are largely made of two different plastics: polyethylene and polypropylene. Both plastics are characterized by universal areas of application. They are light, durable and highly resistant to heat, cold and pressure.
Exactly these properties are also required for concrete. The research team therefore started shredding the disposable products and mixing them with cement. In several runs they tested different dosages of plastic waste from disposable protective coats in the concrete, ranging from 0.1 to 0.3 vol.%. Apparently with success, as Kilmartin-Lynch says: “Our research shows that adding the right amount of shredded protective equipment can improve the strength and durability of concrete.”
Plastic significantly increases the durability of concrete
According to the test results, the compressive strength of the concrete increased by 15 percent, the elasticity by 12 percent and the resistance to bending loads by as much as 21 percent. In addition, the scientists examined the concrete-plastic mixture with ultrasound for micro-cracks and holes. Here too, they were able to establish a positive effect. The overall quality of the concrete increased by two percent. ‘This is probably because the protective sheaths support the bond between the cement and the aggregates and thus limit the formation of micro-cracks,’ say the researchers.
The team was able to achieve similarly good results in a previous plastic glove test. It is worth noting that the quality of the concrete decreases again if too much plastic is added. Apparently, the scientists have reached just the right point with their research.
For research group leader Jie Li, the findings could lead to a win-win situation: a higher quality of building material while also recycling plastic waste: “We have all seen disposable masks lying around on the street. But even if they are disposed of correctly, such waste simply ends up in the landfill.” That can now come to an end, Li said: “With our circular economy approach, we can keep these materials out of landfill while realizing their full value and making better products — it would be a win-win situation for all parties.”
Mixing corona scrap and logistics can lead to problems
However, there are still some questions about recycling PPE. So far, the research group has only mixed “pure” plastic waste into the concrete, namely protective jackets, masks or rubber gloves. The next step is to mix and add different items to check their properties.
The scientists also see potential problems in waste logistics: “However, one of the biggest challenges for the sustainable use of PPE in the construction industry is a continuous supply of the material,” the group says. In addition, a reliable process must be developed to decontaminate the plastic waste before it can be reused.
If these questions are answered in the near future, the construction industry could take a step towards solving the plastic waste problem.
sources: scinexx, studying 1, studying 2, studying 3