Waste
Let’s talk trash.
Building on Ray C. Anderson's industrial legacy, we believe transportation will thrive by adopting circular, waste-free practices and using existing solutions, like road paving, to improve infrastructure performance.
Waste tires are low-hanging fruit; we see them scattered on roadsides, riverbanks, and in illegal dumps throughout our communities. It’s pervasive, but the solutions at scale already exist and are easily within reach.
The Problem of Waste Tires
Each year, American motorists discard approximately 317 million waste tires, or about one tire per person, which creates over 5.6 million tons of tire waste. While recycling and repurposing rates have improved significantly to an estimated 81%, a substantial portion of these tires still end up in landfills or illegal stockpiles. Stockpiled tires pose severe hazards, including the risk of large-scale, long-burning fires that release toxic pollutants and the potential for groundwater contamination from leaching heavy metals. They also serve as breeding grounds for disease-carrying insects.
Rubber-Modified Asphalt (RMA)
Asphalt pavement containing recycled tire rubber is a key market-driven solution to the problem of tire waste. Rubber-modified asphalt (RMA) is “circular” because it keeps materials in use for as long as possible, while also paving better roads. Transforming a waste product like tires into longer-lasting, more durable, quieter roads is a win for transportation agencies and drivers alike.
Developed almost 50 years ago, RMA isn’t new or unproven, and we can increase the number of miles paved nationally with rubber every year. The global market for modified bitumen, which includes rubberized asphalt, is projected to reach $44 billion by 2035, with road construction being the dominant segment. This growth is driven by the performance benefits of rubberized asphalt, which include:
Extended Pavement Lifespan: It's more durable and resistant to cracking and rutting.
Reduced Noise Pollution: The rubber content creates a quieter driving surface.
Improved Safety: It offers enhanced skid resistance.
Cooling: Reduces surface temperatures of asphalt roads, cooling communities during summer heatwaves.
Circular: It reduces the need for new raw materials and diverts tires from landfills.
Nature-Inspired Innovation
Some advancements inspired by nature include:
Self-Healing Materials: Self-repairing concrete and asphalt can significantly extend the life of roads and bridges by reducing the need for constant maintenance and new materials. These innovative technologies work by either using encapsulated bacteria to produce limestone that fills cracks or by embedding heat-activated materials that seal the pavement. This allows the infrastructure to automatically mend itself, making it more cost-effective, durable, and reliable.
Waste-as-a-Resource: Beyond rubberized asphalt, additional opportunities exist to use the base components of scrap tires as a valuable resource to be repurposed for cleaner, safer, and more productive transportation infrastructure. For example, Tire-Derived Aggregate (TDA) can be used as lightweight fill for road embankments, and Tire-Derived Fuel (TDF) can supplement fossil fuels in industrial processes.
Efficient Processes: Innovations in upcycling and materials processing can incorporate certain fungi and bacteria to break down the vulcanized rubber in scrap tires, a process known as bioremediation, a potential alternative to high-heat processes like pyrolysis. Human transportation systems are also being compared to the natural, underground resource networks of fungi and plants (mycorrhizal networks) to find ways to improve the efficiency and sustainability of human transport.