Astec's Green Asphalt

Well thanks to small quantities of dihydrogen monoxide, otherwise known as H2O, being injected into the hot mixture, it is now possible to mix asphalt at a dramatically lower temperature. When I spoke with Don Brock, CEO of Astec Industries, one of the world’s leading manufacturers of equipment used to make asphalt, he said this new innovation was like “a green tsunami.”

A plant using Astec equipment in Tennessee
Astec’s asphalt recycling technology will save
the USA 90 million barrels of oil per year.

Based in Chattanooga, Tennessee, Astec has already sold equipment for 60 asphalt plants that will use this new technology, with 20 already on stream as operating plants.

Up till now, typical “roller asphalt,” used in most roads, which is a mixture of 5% heavy oil and 95% crushed rock, had to be mixed at 330 degrees fahrenheit. At lower temperatures the mixture would not be viscous enough to properly mix.

Astec’s equipment can now mix concrete at 270 degrees, crucially below the 285 degree boiling point. By achieving sufficient viscosity at 270 degrees, far less emissions occur because the asphalt mixture isn’t boiling. It also requires less energy. This is a breakthrough.

We aren’t talking small quantities here. Each year, 750 million tons of asphalt is poured and rolled in the USA, about 90% of it to resurface existing roads. Brock explained that their new technology to mix asphalt at a lower temperature, combined with their new equipment that can grind and recycle more of the asphalt from old roads will increase the amount of old asphalt that can be reused in new roads from today’s 15% to 50%. The amount of oil that would be saved in this manner in the USA each year, according to Brock, was equivalent to one week of imported oil – about 90 million barrels.

Astec’s technology to up the recycled content of new roads from 15% to 50% will also save about 250 million tons of rock each year. Every year in the USA about 3.0 billion tons of rock are quarried, about 10 tons per person per year. About 25% of that is used for asphalt, 25% for concrete, and the rest is used for base rock under buildings, canals, embankments and roadbed. We expect technology to deliver solutions to huge environmental and resource challenges – in Astec’s case, it’s happening already, and on a very huge scale.

Discussions about technology enabled conservation rarely deal with something as fundamental as asphalt. But Astec’s new products demonstrate that even – or especially – in areas as basic as how we build our roads, immediate and huge environmental and economic advantages are still to be won. Given that Astec is the world leader in manufacturing tools to recycle, mix and lay asphalt, with these new technologies already rapidly coming on stream, their innovations are as fine an example of the greentech revolution as any.

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