By Saumya Jain
Engineers at the Virginia Department of Transportation (VDOT) are studying a new type of asphalt mixture, called recycled plastic modified asphalt mixture (RPM), that could replace traditional asphalt mix. While limited research on the technology says it is a win-win for both improving longevity of roads and redirecting plastic waste from landfills, VDOT wants to confirm that the new mixture does not result in microplastic entering the environment through water runoff.
Along with detecting microplastic in water runoff, the study also aims to ensure a reliable source of materials, test methods of incorporating recycled plastics, test sustainable plant operations, ensure the health and safety of workers using the materials and changes needed in paving practices. Through field tests, the study will also compare the performance of the RPM asphalt mixture to VDOT’s typical control mixes and will evaluate its short- and long-term performance.
Although this technology has been in use for a while in parts of Asia, Africa, and Europe, the state of Virginia, along with California and Missouri, are the first few states to test it out in the U.S. Researchers and contractors working with this technology believe that not only does it recycle plastic waste, it is also expected to reduce life cycle cost, resurfacing frequency, energy consumption, and greenhouse gas emissions, while improving road durability and safety for construction workers. According to Rajagopalan Vasudevan, a scientist experimenting with plastic roads in India, “a regular road requires 10 tons of bitumen for each kilometer (0.62 miles). A plastic road, however, requires only nine tons of bitumen and one ton of waste plastic for coating So, for every km, the plastic roads save as much as one ton of bitumen.” And since petroleum is heated to extract bitumen, it is believed that with every ton of bitumen left out, as much as a ton in CO2 emissions is saved.
While China may be the largest manufacturer of plastic, the U.S. is the largest generator of plastic waste (46 million tons in 2016), according to research published in Science Advances. Less than 10 percent of that is recycled every year. According to Doug Woodring, the founder of Ocean Recovery Alliance: “…plastic roads, if done to scale, in combination with other uses for reclaimed plastic, like concrete and fuel, will offer an opportunity to absorb hundreds of thousands of tons, almost overnight.” While incorporating plastic into asphalt may advance plastic waste management and improve pavement quality, resurfacing projects alone cannot absorb 46 million tons of annual plastic waste. And as the EPA recommends, it is imperative to reduce the consumption and production of single-use plastics to make any significant reduction in plastic waste generation.