You can recycle your old computer parts into asphalt

Americans throw away a couple million tons of unwanted computers, cell phones, TVs and other electronics every year. Researchers in China, a major destination of the waste, say they know how to get rid of this mounting e-waste: Recycle the nonmetal components of the printed circuit boards found in many electronics for use as an additive to make asphalt more durable. Pavement engineers say it’s not such a bad idea — but unless several potential roadblocks are cleared, don’t expect to drive down a highway paved with old computer parts anytime soon.

Asphalt is the dark, sticky material that binds rocks, gravel and sand together to make the pavement that covers more than 90 percent of U.S. roads. But as anyone who has ever driven down an old highway knows, asphalt is not immune to cracking in the freezing cold or deforming in the sweltering heat.

To recycle more garbage, “people have been dumping all sorts of stuff in asphalt,” says Rajib Mallick, an associate professor of civil and environmental engineering at Worcester Polytechnic Institute in Massachusetts — old tires, ground-up toilets, glass and shingles, to name a few. It can be a good way to reuse unwanted junk, Mallick says, if it improves the asphalt and is environmentally safe.

Given the growing number of unwanted electronics, Zhenming Xu of Shanghai Jiao Tong University in China decided to see if printed circuit boards might do the trick. They crushed the circuit boards into a fine powder and then removed all the metal, leaving behind mainly glass, resins and fibers. Next, they mixed the powder with asphalt and tested the asphalt’s properties at high temperatures. Adding the recycled material made the modified asphalt more viscous and therefore stiffer than unmodified asphalt, the researchers reported in the journal Environmental Science & Technology. Stiffer asphalt should make for a pavement that stands up better to heat.

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