The annual cost of potholes in England is estimated at around £14.4 billion, according to economic consultancy CEBR. And climate change is only making the situation worse, with excessive heat causing more cracks and extreme flooding leading to greater erosion.
Now a team from Swansea University believe they have discovered a solution: self-healing asphalt that repairs itself when it cracks, preventing the formation of potholes. They believe it can extend the life of a road by 30%.
Along with scientists from King’s College London and from Chile, they have created a bitumen (a sticky black substance used in road surfaces because of its waterproofing and adhesive properties) that can mend cracks in asphalt (usually crushed stone, sand and gravel, bound together with bitumen). Incredibly, they did it using plant spores.
Potholes typically form from small cracks on road surfaces that are created by the weight of traffic over time. Water seeps in and erodes the asphalt; this erosion is exacerbated by freezing and thawing in winter.
The scientists used a type of AI known as machine learning to study organic molecules in complex fluids such as bitumen.
They then mixed in tiny porous plant spores soaked in recycled oils. When the road surface is compressed by passing traffic, it squeezes the spores, which release their oil into any nearby cracks and seals them.
Promising lab results
In laboratory experiments, this advanced asphalt material was shown to completely heal a microcrack on its surface in less than an hour.
Dr Francisco Martin-Martinez from King's College London said: "In our research, we wanted to mimic the healing properties observed in nature. For example, when a tree or animal is cut, their wounds naturally heal over time, using their own biology. Creating asphalt that can heal itself will increase the durability of roads and reduce the need for people to fill in potholes.
“We are also using sustainable materials in our new asphalt, including biomass waste. This will reduce our dependence on petroleum and natural resources," added Martin-Martinez. "Biomass waste is available locally and everywhere, and it is cheap."
Main image credit: Getty Images
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