Monday, September 15, 2014

The New Alchemy: How Self-Healing Materials Could Change the World

Scientists are cooking up asphalt, concrete, and metals that heal themselves. That means smarter and stronger infrastructure—and just a dash of magic.

Once, alchemy ruled our understanding of the material world. Part science and part mysticism, its practitioners experimented with alloys, searched for a universal solvent, and hoped for a philosopher's stone—a substance that turned to gold any metal it touched.

These days, materials science takes a more rigorous multi-disciplinary approach to this sort of engineering. Materials scientists design and discover extraordinary variations on the metals, ceramics, and polymers we think we know. And lately, they're taking their cues from how the human body heals itself, transmuting those mechanics into asphalts, concretes, and metals that can mend their own cracks.

Self-healing or "smart" materials may seem as magic as the alchemy of old, but they carry the very real potential to change our roads, buildings, and means of transportation.

With a Touch of Heat, Steel-Wool Asphalt Lives On

As TripNet reported last year, more than one-quarter of major urban roads in the U.S.—Interstates, freeways and other arteries—have pavement in substandard shape. Heavy with potholes and tears, these rough-riding roads incur the average American driver $377 annually—$80 billion nationally—in operating and repair costs. And a recent estimate from the American Society of Civil Engineers shows that combined, the economic losses of decaying roads, bridges, and other infrastructure zaps $129 billion per year from federal coffers.  

Clearly, we need to mix better asphalt—stronger asphalt, less costly to repair.

Which is what Erik Schlangen has done. Simply by mixing in strands of steel wool to asphalt's usual combination of pebbles and bitumen, the Dutch civil engineer at Delft University has successfully created a road-ready material that’s practically self-healing. As he puts it, it heals itself “with a little bit of help from the outside.”

In the video of his TED talk, you can watch Dr. Schlangen demonstrate his miracle asphalt onstage: In front of an audience of undergrads, he karate-chops a block of asphalt into two. As he begins to talk about how nice it is to drive on asphalt, he places the two pieces side-by-side in an industrial microwave.

For the rest of the story: http://www.citylab.com/tech/2014/09/the-new-alchemy-how-self-healing-materials-could-change-the-world/380075/

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