The idea is being advanced by a research team at Edith Cowan University (ECU) in Australia, which seeks to give a new purpose to plastic waste, reducing its environmental impact while strengthening the durability of road infrastructure.
According to PhD candidate Ali Ghodrati, the lead researcher, “repurposing these common plastics, which would otherwise end up in landfills or the ocean, not only offers a practical solution to plastic pollution but also increases the strength and longevity of our roads.”
The challenge is urgent: in 2019, global plastic production reached around 460 million tonnes. However, only 9% of the total was recycled, 12% incinerated, and nearly 79% ended up in landfills or the natural environment. Projections suggest that by 2050, annual production will exceed one billion tonnes.
Stronger roads with less carbon
Although the use of plastics in pavements dates back to the 1990s, the novelty of this study lies in the integration of plastic waste, reducing the reliance on virgin raw materials and helping mitigate climate change by lowering the carbon footprint of roadworks.
ECU researcher Nuha Mashaan highlights the transformative potential of this approach: “What excites us is the double benefit: helping the environment while creating more resilient and sustainable roads. It’s an innovation capable of driving real change for both communities and industry.”
Incorporation methods and environmental risks
Team member Themelina Paraskeva explains that there are three main methods for incorporating plastics into pavements: wet, dry, and mixed. The choice affects not only performance but also environmental risks such as the release of microplastics.
“The wet process ensures better material compatibility and reduces long-term risks like microplastic emissions. The dry method, while simpler to implement, can cause uneven dispersion and greater release of particles as roads wear,” adds Mashaan.
According to the team, hybrid solutions could balance sustainability and performance, aligning with circular economy principles that prioritize reuse, recycling, and resource recovery.
Not all plastics are equal
However, “not all plastics are suitable for road construction,” warns Mashaan. The determining factor is the melting point: bitumen is mixed at temperatures between 140 ºC and 180 ºC, which makes thermoplastics—such as those from shopping bags and milk bottles—ideal for this application, as they melt easily without generating harmful by-products.
Still, challenges remain. At high concentrations, plastic additives can weaken asphalt, making it more brittle. There are also environmental concerns, from fume emissions to the risk of micro- and nanoplastic release during use under traffic and weathering conditions.
“Although laboratory and small-scale tests are promising, it is essential to conduct trials under real-world conditions, across different climates and traffic scenarios, to conclusively validate the performance and environmental safety of plastic-modified roads,” concludes Ali Ghodrati.
Source: Sustentix
