Research at Royal Melbourne Institute of Technology (RMIT University) in Melbourne, Australia paves the way for used face masks in recycled concrete. Researchers say they have shown that single-use disposable face masks could be used successfully in recycled concrete aggregate for road paving.
Highlights
• A new & low carbon strategy is proposed to reduce pandemic-generated waste
• The inclusion of shredded face mask can improve ductility, flexibility & strength
• The disposed face masks can be used for pavement base/subbase applications
Click to enlarge
The new road-making material is a mix of used shredded face masks (SFMs) and processed building rubble developed at RMIT University. According to an RMIT press release:
• Final product is designed for use is base layers of roads and pavements
• Mixture meets civil engineering safety standards
• Analysis shows the face masks help to add stiffness and strength to the final product
• Mixture performs well when tested for:
-stress
-acid resistance
-water resistance
-strength
-deformation
-dynamic properties
• Meets all the relevant civil engineering specifications
In Australia alone, about 3.15 million tons of recycled concrete aggregate (RCA) is added to stockpiles each year rather than being reused. The experimental study was conducted with a small amount of unused surgical face masks. It identified an optimal mixture that delivers on strength while maintaining good cohesion between the two materials: 1% shredded face masks to 99% RCA.
Recycle of face masks process. Click to enlarge.
RMIT University (formerly the Royal Melbourne Institute of Technology and Melbourne Technical College) is a public research university in Melbourne, Australia and has been rated as the top art and design university in Australia. The researchers’ study will be featured the weekly journal Science of the Total Environment, published by Elsevier—”an international multi-disciplinary journal for publication of novel, hypothesis-driven, and high-impact research on the total environment, which interfaces the atmosphere, lithosphere, hydrosphere, biosphere and anthroposphere”.
Lead author of a report on the study, Mohammad Saberian said, “This initial study looked at the feasibility of recycling single-use face masks into roads, and we were thrilled to find it not only works, but also delivers real engineering benefits! We hope this opens the door for further research, to work through ways of managing health and safety risks at scale, [as well as] investigate whether other types of personal protective equipment (PPE) would be suitable for recycling.”
According to the study’s abstract, “for the first time”, a series of experiments were conducted on the blends of different percentages of the SFM added to the RCA for road base and sub-base applications:
• modified compaction
• unconfined compression strength
• resilient modulus tests,
RCA mixed with 3 different percentages of SFM – 1%, 2% and 3% – satisfied the stiffness and strength requirements for pavements base/sub-base.
The introduction of the SFM not only increased the strength and stiffness but improved the ductility and flexibility of RCA/SFM blends. The inclusion of 1% SFM to RCA resulted in the highest values of unconfined compressive strength (216 kPa) and the highest resilient modulus (314.35 MP).
However, beyond 2%, increasing the amount of SFM led to a decrease in strength and stiffness.
A free download pdf is available now ahead of official publication later this year, and some alterations may be made before then. M. Saberian, J. Li, S. Kilmartin-Lynch, et al., “Repurposing of COVID-19 single-use face masks for pavements base/sub-base”: with co-authors RMIT Indigenous Pre-Doctoral Research Fellow Shannon Kilmartin-Lynch and Research Assistant Mahdi Boroujeni, is published in “Science of the Total Environment” (DOI: 10.1016/j.scitotenv.2021.145527).
In related work, the RMIT researchers said that they have also investigated the use of shredded disposable face masks as an aggregate material for making concrete, with promising preliminary findings.
Abstract
The coronavirus (COVID-19) pandemic has not only created a global health crisis, but it is also now threatening the environment. A multidisciplinary collaborative approach is required to fight against the pandemic and reduce the environmental risks associated with the disposal of used personal protective equipment (PPE). This paper explores an innovative way to reduce pandemic-generated waste by recycling the used face masks with other waste materials in civil constructions. In this research, for the first time, a series of experiments, including modified compaction, unconfined compression strength and resilient modulus tests, were conducted on the blends of different percentages of the shredded face mask (SFM) added to the recycled concrete aggregate (RCA) for road base and subbase applications. The experimental results show that RCA mixed with three different percentages (i.e., 1%, 2% and 3%) of SFM satisfied the stiffness and strength requirements for pavements base/subbase. The introduction of the shredded face mask not only increased the strength and stiffness but also improved the ductility and flexibility of RCA/SFM blends. The inclusion of 1% SFM to RCA resulted in the highest values of unconfined compressive strength (216 kPa) and the highest resilient modulus (314.35 MP). However, beyond 2%, increasing the amount of SFM led to a decrease in strength and stiffness.
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IMPORTANT LINKS:
“Routes du Monde (World Highways)” RMIT article: www.worldhighways.com/wh5/news/face-masks-breathe-life-roads
Free Elsevier PDF download of Researchers’ Study and
photos of process, charts of resilience, etc… : www.sciencedirect.com/science/article/pii/S0048969721005957