Researchers recycle PPE to make concrete stronger

RMIT University engineers have developed a new method of recycling personal protective equipment (PPE) to make concrete stronger, which could significantly reduce the waste generated by the pandemic.

Since the start of the COVID-19 pandemic, approximately 54,000 tonnes of PPE waste have been generated per day worldwide. Around 129 billion disposable face masks are used and thrown away around the world each month.

In three separate studies, the RMIT School of Engineering team investigated the feasibility of recycling three key types of PPE – isolation gowns, face masks and rubber gloves – into concrete.

Published in journals Building Materials Case Studies, Total Environmental Science and Cleaner Production Journalstudies have found that shredded PPE can increase concrete strength by up to 22% and improve crack resistance.

In each study, disposable face masks, rubber gloves, and isolation gowns were first shredded and then embedded in concrete at various volumes, between 0.1% and 0.25%.

The search found:

  • Rubber gloves increased compressive strength by up to 22%
  • Isolation gowns increased resistance to bending stress by up to 21%, resistance to compression by 15% and elasticity by 12%
  • Face masks increased compressive strength by up to 17%

RMIT’s industrial partner, Casafico, now plans to use these research results in a field project.

The study’s first author, PhD researcher Shannon Kilmartin-Lynch, said the research brings a circular economy approach to the challenge of healthcare waste management.

“We urgently need smart solutions for the ever-growing pile of waste generated by COVID-19 – this challenge will persist even after the pandemic is over,” Mr Kilmartin-Lynch said.

“Our research found that incorporating the right amount of shredded PPE could improve the strength and durability of concrete.”

Co-lead author Dr Rajeev Roychand said construction industries around the world have great potential to play an important role in turning this waste into a valuable resource.

“Although our research is in its early stages, these promising early findings are an important step towards developing effective recycling systems to keep disposable PPE waste from ending up in landfills,” said Mr Roychand.

Corresponding author and research team leader Prof Jie Li said PPE waste – from both healthcare and the general public – had a significant impact on the environment.

“We’ve all seen disposable masks littering our streets, but even when this waste is disposed of properly, it all ends up in landfill,” Li said.

“With a circular economy approach, we could keep this waste out of landfills, while leveraging the full value of these materials to create better products. It’s a victory on all fronts.

Li said the next stage of research is to assess the potential for mixing PPE streams, develop practical implementation strategies and work on field trials.

The RMIT team wants to collaborate with the health and construction industries to further develop the research.