potholes

People have generated 8 billion tons of plastic waste over time and less than 10% of it has been recycled. Millions of tons of it escapes into the oceans. Plastic piles up virtually everywhere on earth.

There are many approaches to dealing with the plastic waste problem and no one of them is a magic bullet. Engineers at Stanford University have investigated the prospects for upcycling plastic waste for use in infrastructure like buildings and roads.

They used a mix of computer modeling, scientific research, experimental and field data to analyze the potential for using plastic waste in infrastructure.

Among their findings is that recycled glass fiber reinforced polymer composite – which is a tensile plastic commonly used in car, boat, and plane parts – is a promising material for reuse in buildings.

Roads in which waste plastic is melted down and mixed with conventional paving materials are becoming more common around the world. India has installed over 60,000 miles of these roads. Studies show that roads containing waste plastic have the potential to perform better than conventional roads. They can last longer, are more durable, can tolerate wide temperature swings, and are more resistant to water damage, cracking, and potholes. Such roads rely less upon virgin fossil resources, which is obviously advantageous.

Upcycling plastic waste in infrastructure is attracting increasing interest because it creates value from something that is strictly a liability and may end up having regulatory advantages as societies move toward more environmentally friendly and sustainable policies.

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Can we use plastic waste to build roads, buildings, and more?

Photo, posted October 7, 2022, courtesy of the Grand Canyon National Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The country of Ghana has an ambitious plan to recycle and reuse as much plastic waste as it produces each year (which is over a million tons) by 2030. As part of this plan, they have started to pave roads in Accra, the capital city, with asphalt containing a slurry of used plastics – shredded and melted bags, bottles, and snack wraps. Only a quarter of Ghana’s roads are currently paved, so waste plastic has many opportunities for use in paving.

Plastic roads first appeared in India two decades ago. There are now over 60,000 miles of them in that country. Several countries have only recently built their first plastic roads including South Africa, Vietnam, Mexico, the Philippines, and the United States.

Studies have shown that roads containing waste plastic have the potential to perform as well or better than traditional roads. They can last longer, can tolerate wide temperature swings better, are stronger and more durable, and are more resistant to water damage, cracking, and potholes.

Ordinarily, asphalt for roads consists of 90 to 95% aggregate – typically some mixture of gravel, sand, and limestone – and 5 to 10% bitumen, which is a black gooey substance extracted from crude oil that binds the aggregate together. Plastic-enhanced roads replace varying amounts of the bitumen (often as little as 4-10%, but sometimes much more), with plastic that is actually a stronger binding agent.

Plastic roads reduce the amount of bitumen in roads, thereby reducing carbon emissions. The plastics are not heated enough to release gases and the roads do not appear to shed microplastics. Plastic roads will not solve the world’s plastic waste problem, but they can help by diverting lots of plastic from landfills.

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How Paving with Plastic Could Make a Dent in the Global Waste Problem

Photo, posted June 4, 2010, courtesy of Sustainable Initiatives Fund Trust via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Upcycling Plastic Waste | Earth Wise

People have generated 8 billion tons of plastic waste over time and less than 10% of it has been recycled. Millions of tons of it escapes into the oceans. Plastic piles up virtually everywhere on earth.

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Paving With Plastic | Earth Wise

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