Are Cigarette Butts the Secret to Better Roads?
A cigarette butt on the pavement is disgusting. A cigarette butt in the pavement, though—well, that's another story. Scientists writing in the journal Construction and Building Materials say butt-studded asphalt could be the wave of the future.
Tobacco companies produce about 6 trillion cigarettes every year, which leads to about 1.3 million tons of butts.
Lead author Abbas Mohajerani is an engineer at RMIT University in Melbourne, Australia. "In Australia alone, people smoke about 25 to 30 billion filtered cigarettes a year and, of these, about 7 billion are littered," he said in a statement.
Butts that end up in a landfill are not much better off. They're slow to decompose, and when they do, they release their nasty chemicals into the soil and water around them.
Mohajerani knows that we're not going to get everyone on Earth to stop smoking. But there may be other things we can do. He and his colleagues at RMIT have begun incorporating cigarette butts into different construction materials.
They started with bricks. And while it may sound like a weird, abstract art project, the addition of cigarette butts actually makes a lot of sense. The very thing that makes cigarettes disposable—their flammability—also can help make better, cheaper bricks. The researchers found that changing a brick's composition to include just 1 percent cigarette waste reduced the amount of energy required to fire that brick by a whopping 58 percent.
The waste-added bricks also were better at insulating than standard bricks—which could reduce a brick building's heating and cooling costs.
For their latest study, the team sealed cigarette butts in bitumen and paraffin wax, then combined them with hot asphalt. The resulting pavement was not only functional but, like the bricks, better for the surrounding environment. The inclusion of the bitumen decreased the pavement's ability to conduct heat, which could help keep already overheated cities cooler.
Most importantly, both the bricks and the asphalt imprisoned the cigarettes' toxic chemicals and prevented them from poisoning their surroundings.
"This research shows that you can create a new construction material while ridding the environment of a huge waste problem," Mohajerani said.
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