The City of Battle Ground is paving the way toward reducing landfills through a pilot program incorporating plastic wastes into road asphalt.
This initiative, in collaboration with Washington State University (WSU) Pullman and the Washington Transportation Improvement Board (TIB), is set to test the structural integrity of road pavement incorporating plastic waste additives. The grind and overlay project on Eaton Boulevard stretches from Southeast Grace Avenue to Northeast 157th Avenue. Under this project, workers ground 2 inches off the road to enhance its structural integrity.
Battle Ground received $336,974 in funding from TIB after accepting the pilot program. Last week, city engineer and project lead Ryan Jeynes specified that the contract amount for construction had risen to $585,093.20. Jeynes explained the incorporation of waste plastics in asphalt is the first to be studied by the TIB in Washington.
“Part of why we're participating is to help gain additional research for this project … It's once you start putting this into practical use, that's when you typically start getting more of that data from my understanding,” Jeynes said.
Lakeside Industries, the Eaton Boulevard project contractor, created the experimental mixture by hot-mixing the broken-down plastics, provided by Driven Plastics, into asphalt. The mixture was settled in mid-September, with the striping set to be completed by press time.
The collaboration began when Battle Ground submitted a funding application for TIB. Deputy Director Chris Workman noted that Eaton Boulevard's traffic patterns made it an ideal candidate for this pilot program.
“It had the traffic volumes that we were looking for, along with a mix of local and non-local traffic. We wanted a road where the traffic volumes wouldn't change too much throughout that corridor,” Workman explained.
The application of mixing waste plastic additives has gained traction in other places as countries around the world have begun declining shipments of plastic waste from the U.S. WSU Pullman Civil & Environmental Engineering Professor Haifang Wen began researching asphalt mixtures incorporating waste plastics nearly three years ago for this reason.
“Since the late 2010s, countries have started to decline plastic waste shipments from the U.S., leading to a need to keep waste plastics out of the landfill,” Wen explained. “So that creates a lot of issues in [the] U.S. domestically, [including] where to use it, where to put it. The recycling rate in the states is pretty low, and we had to find a way to use it.”
For the past three years, Wen and graduate students have conducted lab and fieldwork for the project, funded through grants from King County and TIB. While pilot programs in other states have experimented with small percentages of waste plastics — typically not exceeding half a percent — the Eaton Boulevard project marks a significant advancement by including three-quarters of 1% of plastic waste in the asphalt mixture.
The project spans three-quarters of a mile along Eaton Boulevard and divides the new overlay into four segments. Between Grace Avenue and Commerce Avenue, the road — particularly near the railroad crossing, which experiences heavier traffic — features one section paved with standard hot-mix asphalt and another with experimental asphalt. A similar division is applied between Commerce Avenue and 157th Avenue, an area with lighter traffic.
Wen explained that 6 pounds of waste plastics were used for both the two segments of Eaton Boulevard. Each summer, Wen and a team of graduate students will review the structural integrity of the four paved sections — two control and two experimental — and report their findings back to the TIB.
Wen hopes the results and other experiments lead to more sustainable construction in the United States.
“It is the first project that uses [this] much material with the plastic. I think it's a good start [to] give us a good idea, and, hopefully, we can use more and more [plastics] for construction, creating a good use for recycled material instead of letting it go to landfill or getting into the water,” Wen said.
Research for the project, including both lab and field work, cost around $200,000, funded by grants from agencies including King County and the TIB. Wen is optimistic that the results will lead to more widespread adoption of waste plastics in road construction, paving the way for a more sustainable future.
“We're trying to make some good decisions in the industry, and, as far as sustainability goes, they're doing a lot of good research. [I’m] happy with what they've done so far,” Workman said.
Wen noted the study of Eaton Boulevard’s stability will take more than a few years.
