Self-Healing Asphalt Holds Promise for U.S. Infrastructure

Emerging technology seeks to stop potholes before they start

  • Scientists are exploring the addition of steel fibers and iron oxide nanoparticles in conventional asphalt
  • The higher cost of self-healing asphalt can be offset by lower maintenance costs
  • The technology is in its infancy, but a pilot project in the Netherlands may offer some lessons in the coming years

America’s infrastructure is in dire need of repair. Though states and municipalities are currently looking at ways of financing new infrastructure projects, a new “self-healing” asphalt may also be employed in the short term to keep commuters moving.

The average lifespan for a stretch of asphalt is anywhere from seven to 10 years when its properly laid. However, wear-and-tear from exposure to the elements, as well as erosion from thousands of car tires can degrade it over time. Self-healing asphalt, which is designed to repair itself as cracks or holes appear, could potentially double that lifespan.

Scientists are currently looking at a number of ways to create asphalt that will heal itself. One entails laying asphalt with steel fibers. When a crack or pothole appears, the steel fibers can be heated trough induction. The asphalt will fill in any cracks or holes as it melts.

Notably, one stretch of self-healing asphalt is currently being tested in the Netherlands. The material, which utilizes steel fiber, is nearing the end of the conventional asphalt life cycle having been laid in in 2010.

Another method requires mixing asphalt with iron oxide nanoparticals that can be heated, rather than steel fibers. The heated nanoparticles melt bitumen in the paved road so that it can fill any gaps.

A third technique entails combining micro-capsules of sunflower oil with asphalt. As cracks start to form, the capsules burst and soften the surrounding pavement, allowing the cracks to heal. Notably, this method works best for small fissures since the capsules burst before they can become potholes.

Some researchers are also exploring the possibility of using carbon nanotubes to repair asphalt on the road, but these techniques are still very much in their infancy.

Benefits and costs

Self-healing asphalt is not cheap. According to some estimates, laying a stretch of self-healing road similar to the one being used in the Netherlands costs an estimated 25% more than traditional asphalt. According to the New Jersey Institute of Technology, American drivers spend an astonishing 14.5 million hours stuck in traffic every single day, due in part to the declining quality of roads. Moreover, poorly maintained infrastructure cost drivers roughly $23 billion annually.

The additional cost of using self-healing asphalt could present a hurdle to small towns or municipalities struggling to find enough money to fix existing potholes. However, in the long run, this technology could save small towns money since they will not have to repave roads as frequently.

Right now, these self-healing asphalt technologies are still in their infancy. As such, state departments of transportation and local authorities are not yet rushing to incorporate it into their large-scale infrastructure development plans. However, it could ultimately become a solution for reducing overall infrastructure maintenance costs, and keeping roads safe for drivers for decades to come.

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