Lecturer invents microcapsules to repair road surfaces

A new method for self-healing asphalt could potentially increase a road's lifespan.

Alvaro Garcia, a lecturer at the Faculty of Engineering at the University of Nottingham, has developed a new method of repairing roads using sunflower oil capsules. He got the idea from watching the Spanish version of the TV show MasterChef, where a contestant used the spherification technique – which is the controlled jellification of a liquid to form spheres – in a recipe.

Garcia’s idea was to put oil capsules into the asphalt in the road-building process. Then, when the roads begin to crack, the capsules break open, softening the asphalt and encouraging it to blend back together. This, Garcia believes, should both repair small faults in the road and also prevent more serious ones occurring. “Our preliminary results showed that the capsules can resist the mixing and compaction processes without significantly reducing the physical and mechanical properties of asphalt,” says Garcia. “More importantly, we found that the cracked asphalt samples were restored to their full strength two days after the sunflower oil was released.” The capsules named ‘Capheal’ could potentially increase a road’s lifespan and save costs in the long term. The research is part of a bigger investigation on pavement engineering and sustainable materials within the Nottingham Transportation Engineering Centre and has being funded by Highways England, a government-owned company whose responsibility is maintain and improves England’s motorways and major roads.

Companies are constantly working on new ways to make road building more efficient and environmentally friendly. A Dutch company has devised a way to recycle toilet paper into construction materials, while a researcher in Australia has created a better-performing asphalt by adding cigarette butts. What other materials that could be added to asphalt to improve its durability?