As we already know, very little plastic is actually recycled. “The vast majority ends up being dumped, most of it in landfills.” Much plastic also ends up as litter, a portion of that gets into waterways and washes out to sea. The vast amount of plastic fouling the oceans and the many problems it causes is well-documented.
Bitumen is a substance that is used to make asphalt; asphalt is used to build and repair roads. Plastic and bitumen are similar polymers produced from petrochemicals. Plastics are strong and last a long time–features also useful for roads.
As a result, recycled plastic is now beginning to be used for road building. A project in the Netherlands–a bicycle track–was made from 70% recycled plastic and 30% polypropylene. The track was constructed from prefabricated sections.
“Prefabricated plastic roads should last 2 to 3 times longer than conventional roads and cost less … mainly because construction times would be reduced by almost two-thirds.” The plastic road sections, when replaced themselves, could then also be recycled.
Another project in California uses recycled plastic mixed with hot bitumen to make asphalt. In this case, a variety of mixes are being tested–using plastics that are “not easily or cheaply recycled” and thus usually end up in landfills. Other projects have involved recycled plastic being used for “roads, car parks, and airport runways” in various places including Britain, India, and Australia.
“Cleaning and sorting plastic made out of multiple polymers can be relatively expensive,” but using this plastic for road building “is cost-effective.” Plus, plastic used for roads is that much less going into landfills.
Read the article (Recycling, The Economist, September 13, 2018).
For more information about recycling and plastics, search the Science Primary Literature Database and the Headline Science Database.
