Missouri engineers testing use of plastic waste in road pavement mixtures

An asphalt paving machine prepares to receive new asphalt paving material made with recycled plastic […]

An asphalt paving machine prepares to receive new asphalt paving material made with recycled plastic while resurfacing a portion of Stadium Boulevard in Columbia. Image: University of Missouri

Engineers at the University of Missouri are partnering with Dow and the Missouri Department of Transportation (MoDOT) to test mixing plastic waste into the asphalt pavement mixtures for possible use on American roadways and bridges.

Asphalt pavement mixtures are typically created from a mixture of asphalt and other materials (aggregates) such as stone, sand, or gravel, said Bill Buttlar, the Glen Barton Chair in Flexible Pavements in the Department of Civil and Environmental Engineering at U Missouri. He said in a news release that the chemical makeup of plastic helps it become a good product for road pavement mixtures.

“Plastic was developed to be durable and has a shelf life of hundreds of years,” Buttlar said in a statement. “Asphalt and plastics are also chemically similar because they both come from crude oil, so they can be mixed together. They aren’t perfectly compatible, but it’s close enough that engineers and chemists can work together to find a workable solution.”

Inside the Mizzou Asphalt Pavement and Innovation Lab (MAPIL), located in the MU College of Engineering, engineers and students are determining how to incorporate various types of single-use, polyethylene-based plastic waste into asphalt pavement, including drinking bottles, grocery bags, and drinking straws.

MU’s engineers and students get to test their lab-developed mixture in a real-world environment when it is applied as a pavement overlay, or a new layer of asphalt, to a deteriorating section of road surface, along a stretch of Stadium Boulevard in Columbia from College Ave. to U.S. Highway 63 where traffic averages approximately 36,000 vehicles a day. Buttlar said to confirm the results, the team will need to observe the nearly 2-mile test area for at least one year, including one summer and one winter season. He said a pavement overlay should last for at least a decade, or about 12-15 years, before needing to be replaced, and recycled materials such as plastic and tire rubber can also extend pavement life by increasing both its strength and toughness.

The full story can be found on the University of Missouri’s website.