Scientists unveil self-healing asphalt to end potholes

WHY TIS MATTERS IN BRIEF

Many a motorist has been upended by potholes, as their cars clang into one, this might be a way to end them for good.

Self-healing materials are in vogue at the moment with breakthroughs across a variety of fields that include being able to use the tech to heal everything from cracked smartphone screens and catastrophically damaged electronics and robots, to healing cracks in concrete. And that’s before we discuss the creation of the world’s first living materials that not only self-heal but also grow.

Cracks in asphalt are a common sight, but a pain to repair. It is expensive and because the roads need to be closed down for construction, traffic jams occur. Now though researchers at ETH Zurich and EMPA in Switzerland are working on a solution by creating pothole proof, self-healing asphalt, which can be mended using just a magnet field.

Courtesy: ETH Zurich

Bitumen is a sticky, viscous black binder used in road construction, made from petroleum. The bitumen is mixed with aggregate particles for the use of road construction, but slowly crumbles down due to wear and tear, differences in temperature and chemical substances. The cracks that develop are first microscopic, but eventually grow under the weight of traffic.

To make the self-healing asphalt, the binder is mixed with iron oxide nanoparticles, and when these particles are exposed to a magnetic field, they heat up. This heat is then transferred to the bitumen, softening it and thereby healing the cracks. To be completely self-healing though the roads must be constructed entirely using the nanoparticle mixture, but none the less existing potholes can be mended with the new material too to create an intermediary fix.

A few years ago, there was a similar project, but instead of nanoparticles the team used steel wool fibre. However, the main problem with this was that the fibres took too long to heat up, which would mean that it would take several minutes to fix half a metre of road which would have been impractical in the real world.

The iron oxide nanoparticles used in the current project heat up much quicker, eliminating this problem. In addition, iron oxide particle aren’t harmful to human health because they are strongly bound with the bitumen and it’s unlikely they could escape in the first place.

At the moment, and because of the constant road stress, the team say any road using the new material would have to be treated annually using maintenance vehicles equipped with giant magnetic coils to quickly kick-start the healing process, but as the technology improves they also envisage that treatments would have to be applied less regularly.

So, is this the end for potholes? Well, it’s a start… and anything that helps us drink out Starbucks molecular coffee in peace in our future self-driving cars would be most welcome.