Around 1 billion waste tires are produced worldwide each year, but only a small percentage of all those tires are recycled. Most of the rest end up as waste. Now scientists in Australia have found a solution on what to do with all those unwanted rubber rings: turn them into roads.
The way to do this is to mix rubber from old tires with recycled debris from construction materials to produce a new material that can be used for underlays on roads.
The process has been developed by a team of researchers at RMIT University in Melbourne, who say that the mix of recycled materials meets road safety standards and is more flexible than standard materials, making roads less prone to to crack. "Traditional road foundations are made of unsustainable virgin materials: quarried rocks and natural sand," says Mohammad Boroujeni, who led the research.
"Our mixed material is a 100% recycled alternative that offers a new way to reuse tires and construction waste, while also performing strongly on key criteria such as flexibility, strength, and permanent set," he explained, adding: "As We are moving towards a circular economy that can eliminate waste and support the continued use of resources, our recycled mix is the right choice for better roads and a better environment ”.
Roads comprise four layers: a subgrade, a base, and a sub-base covered with asphalt on top. All of these layers must be strong enough to support the weight of the vehicles, but they must also be flexible because stiffness would cause them to crack. The new rubble and rubber mixture has performed well in stress, strength and dynamism tests, among other characteristics with its low shrinkage and good flexibility that reduces the risk of cracking.
Better yet, by turning old tires into useful new road materials, we can help solve a major waste problem. “The solutions to our waste problems will come not only by reducing the amount that goes to landfill and increasing the amount that we recycle; Developing new and innovative uses for our recycled materials is absolutely vital, ”stresses Professor Jie Li, a member of the Australian team.