Building recycled plastic roads

We can pave a future out of the plastic problem by turning it into a kind of tarmac

(Image credit: Maksym Kozlenko/ Wikimedia Commons)

We live in a world where over 400 million tonnes of plastic are produced each year. Of this volume, 75 per cent gets thrown away, damaging ocean life and packing landfills full. Recycling these materials has become more important than ever, and one way people are beginning to tackle this problem is by creating roads out of plastic.

Recycled roads can use up to 684,000 plastic bottles or nearly 2 million single-use plastic bags in every kilometre. Comparing current roads to the properties we see in a plastic bottle, you may wonder how these roads fare in safety. Tests have shown that including plastic into road mixtures actually improves strength, it proving to be twice as strong and withstanding heavy traffic. The reason for their improved durability is thought to be the flexible properties of plastic. Their bounce-back ability after displacement from weight gives them an almost self-repairing property that asphalt roads lack. As well as this, the roads continue to establish the same essential qualities such as being weatherproof while reducing flaking and potholes. Using alternative materials, such as plastic, these recycled roads combat two issues at once.

While putting waste material to use instead of damaging surrounding environments, these roads also cut down on the amount of bitumen used to make asphalt roads. Creating more sustainable roads, less oil will be demanded for production, as fossil fuels are rapidly depleting. For each tonne of bitumen that plastic replaces in these roads, a tonne of carbon dioxide is reduced in production. And why stop at plastic for alternative and sustainable sources? Further projects include the use of old tyres and even the waste products from olive oil extraction.

How are these eco-friendly roads made?

Creating a structurally sound road from plastic seems like a complex task. First the plastic bottles, bags and other items are washed and cut down into small pellets. These are melted at soaring temperatures of 170 degrees Celsius to combine with the asphalt mix. The resulting blend is used by workers to layer smooth roads as they usually would. Pellets can vary in specific plastics, creating roads with slightly different properties. Road manufacturers can choose from three types of plastic pellets to buy, ranging in flexibility and durability. For example, in roads that will be used for the transportation of heavy trucks and machinery, the stronger pellets will be chosen. An example of where plastic varieties are essential is in the Middle East. Here, pellets need to be made from plastics that can resist becoming misshapen in the extreme and constant heat.


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