Bitumen, a material derived from fossil fuel, is used when repairing roads. To provide the world with an alternative, a Norwegian startup has come up with a plant-derived material that could significantly shrink the carbon footprint of our roads.
So how does this work? The company uses a Carbon Crusher machine, which grinds up the top layer of a damaged road and then uses lignin to bind the crushed material. Lignin is a wood-based substance that assists plants in maintaining their woody and firm structure.
Lignin is a byproduct of the paper industry, and by using it for roads, the method becomes even more sustainable. Optimist Daily writes that “because trees capture CO2 as they grow, including lignin sequesters carbon. This shrinks the carbon footprint of road repair so much that the roads essentially become carbon negative.”
“We’re making roads that are part of the solution to the climate crisis, not part of the problem,” says cofounder Haakon Brunell to Fast Company. “And it also happens to be a cheaper, more durable way of rehabilitating roads.”
The company’s proprietary equipment crushes the asphalt into more acceptable material which could be reused. By doing this, the need to create new material is eliminated.
Lignin is way more flexible than bitumen, and in places where the weather is harsh, this is an outstanding characteristic. In Norway, the harsh winters take a real toll on the roads when the ground freezes and thaws repeatedly. According to Hans Arne Flåto, “The conventional binder, bitumen, gets very stiff when we get some frost. It cracks up, and they have to fix it and put new asphalt on. And then you have the same problem next year.”