Is the road to sustainable asphalt paved with recycled end-of-life tires?
In the article “Is the Road to Sustainable Asphalt Paved with Tires?” published on December 11, 2020 in the ASC Central Sceince, Raleigh McElvery – a contributor to Chemical & Engineering News, the weekly newsmagazine of the American Chemical Society – writes that “Mixing waste rubber from scrap tires into asphalt binder is one way to make pavement more environmentally friendly.”
The article touches upon the topic of environment and shows how rubberized asphalt from end-of-life tires proves to be more environment-friendly than the common asphalt concrete. McElvery writes:
“Over 90% of U.S. roads are paved with what’s known as asphalt concrete, which is composed primarily of rocky aggregates and a black, gummy binder that acts as a glue. The binder, a blend of complex hydrocarbons derived mostly from petroleum, generates most of the environmental impact even though it represents just a small portion of the entire mixture. Acquiring, transporting, and refining the binder emits greenhouse gases and volatile organic compounds. During paving, heating the mix of aggregate and binder requires additional energy, producing yet more greenhouse gases and air pollutants. Then, with time, the binder in pavement stiffens from oxidation and begins to crack. As a result, roads demand maintenance and rehabilitation.”
McElvery highlights that tires are made of a mixture of synthetic and natural rubbers, which are heated with sulfur and various auxiliary compounds to form a complex, cross-linked structure.
“This sturdy composition prevents tires from degrading in landfills, but the polymer bonds come apart when the crumb rubber is heated and mixed with binder. As a result, adding crumb rubber to the binder generally yields more performance benefits than adding it to the aggregate.”
Below, we are citing the article published at ASC Central Science, which lists environmental advantages of using tire-derived crumb rubber in rubberized asphalt.
To learn more, please read the full article by Raleigh McElvery at ASC Central Sceince.