In 2021, Missouri added just 1% waste plastic to a two-mile road, that tiny share consumed 10 tons, equal to 750,000 soda bottles

Plastic waste is a persistent challenge, and finding practical ways to reuse discarded material can help reduce the amount that ends up in the environment. In Missouri, transportation officials were exploring one such approach in 2021: incorporating recycled plastic into asphalt pavement.

The project was discussed during the Missouri Highways and Transportation Commission’s September 9, 2021, meeting as part of a broader report on transportation projects, maintenance and innovation.

Recycled plastic tested in Missouri asphalt

Chief Engineer Ed Hassinger said engineers at the University of Missouri were working with Dow and the Missouri Department of Transportation (MoDOT) to test whether plastic waste could be mixed into asphalt pavement for potential use on roads and bridges.


The effort focused on incorporating different types of single-use, polyethylene-based plastic waste into asphalt. The materials being considered included drinking bottles, grocery bags and drinking straws.

At the time of the meeting, the technology was being tested in a real-world paving project on Stadium Boulevard, or State Route 740, in Columbia. The test section covered two miles, extending from College Avenue to U.S. Highway 63.

Although the recycled plastic represented only one percent of the asphalt mixture, the scale of the two-mile project meant that it would use 10 tons of recycled material. According to Hassinger's presentation, that amount was equivalent to about 750,000 soda bottles.

The project was presented as an effort to explore innovative ways of keeping plastic waste from ending up in the environment while also testing its potential application in transportation infrastructure.

The road project was part of a wider transportation discussion

The plastic-recycling test was only one element of the September 9 Commission meeting. Much of the discussion focused on maintaining Missouri's existing transportation network and managing limited resources.

During a workshop on asset management and low-volume minor roads, Eric Schroeter, Assistant Chief Engineer, outlined the department's efforts to maintain and operate that part of the state road and bridge system. He noted that the system included 837 poor bridges and that additional bridges were approaching the point where major repairs, rehabilitation or replacement would be needed.

The department identified five priorities expressed by citizens during updates to the Long Range Transportation Plan: taking care of the existing system, safety, economic development, better transportation choices, and improving reliability while reducing congestion.

The Commission had also approved an Asset Management Deficit Program to address pavement-condition disparities beyond existing asset-management allocations.

Transportation funding remained a concern

The meeting also highlighted the financial pressure involved in maintaining roads and bridges. Director McKenna said the department was making assumptions and educated guesses about resources that could be available for additional maintenance work through maintenance jobs in the Statewide Transportation Improvement Program.

The department discussed the possibility of putting an additional $15 million toward low-volume roads. Commissioner Ecker expressed concern that this amount was insufficient when the transportation system required hundreds of millions of dollars and said the existing allocation of resources was allowing low-volume roads to deteriorate.

At the same meeting, the department's Financial Services Director, Todd Grosvenor, presented a proposed fiscal year 2023 appropriations request totaling $4.1 billion, along with a fiscal year 2022 supplemental appropriations request totaling $74 million.

Innovation alongside road maintenance

The recycled-plastic project stood alongside a range of conventional transportation activities discussed during the meeting, including pavement resurfacing, bridge rehabilitation, emergency repairs and safety improvements.

The Southwest District, for example, was maintaining more than 6,500 miles of road and more than 1,800 bridges. The district also reported work connected with the Governor's Focus on Bridges program and other major transportation projects.

The September 2021 meeting therefore showed both sides of Missouri's transportation challenge: maintaining a large and aging system while looking for new approaches that could potentially make use of waste materials.

For the plastic-asphalt experiment, the key figure was small in percentage terms but substantial in total material: recycled plastic made up just one percent of the mixture, yet the two-mile test section was expected to use 10 tons of recycled material, equivalent to about 750,000 soda bottles.

Source: Missouri Highways and Transportation Commission

FAQs:

Q1. What was the Missouri road project about?

The project tested recycled plastic as part of an asphalt pavement mixture. It was discussed during a Missouri Highways and Transportation Commission meeting in 2021.

Q2. Where was the recycled plastic tested?

The test was conducted on Stadium Boulevard, or State Route 740, in Columbia. The section extended from College Avenue to U.S. Highway 63.