A pothole which heals itself sounds like a road user’s daydream, but international research teams at Swansea University and Kings College London reckon it could come true. The teams have added tiny plant spores soaked in recycled oil to bitumen, which mends cracks as they form by fusing the asphalt back together. In laboratory tests, small cracks were self-repaired within an hour of first appearing. When the road surface is compressed (as by passing traffic) it squeezes the spores’ oil, which softens the bitumen enough for it to flow into small cracks.

Potholes begin when minute cracks form, allowing water in. With the cycle freezing and thawing, plus the weight of passing traffic, eventually these grow until the bitumen collapses into a pothole. “When you close the cracks you prevent potholes forming in the future and extend the lifespan of the road,” said Dr Jose Norambuena-Contreras, one of the researchers. “We can extend the surface lifespan by 30%.” However, it could be two years until the material is scaled up for use on British roads.

Jim Freeman, chair of the BMF thought that any method of potentially solving Britain’s pothole crisis needs support. “This sounds like pothole ‘magic pie’ but if it works as Dr Jose suggests, the whole team would get my vote for a Nobel, a potential lifesaver, literally.”

Written by Peter Henshaw

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