Courtesy Miguel Tremblay
We've all been there. You're driving along, bobbing your head along to the music, when suddenly you hit a pothole and it feels like your suspension is coming apart. It's especially bad here in Minnesota, because our extreme winters take their toll on worn asphalt. What's a gal to do?
One possible solution is a better way to fix potholes. In Duluth, MN, MNDOT workers are experimenting with new ways to hot patch asphalt with recycled materials and microwaves. In wintertime, crews usually have to patch potholes temporarily until summer comes along and they can use hot asphalt to make a more permanent patch. By using a special microwave, they can make hot patches even in bitter cold temperatures, and the recycled materials make for less waste and pollution. The new fix is also faster and cheaper than current methods.
My friend Wendie pointed out some billboards that went up recently in the metro area to promote concrete as a pothole-free alternative. (Wendie also passed along a handful of the articles in this post--thanks, Wendie!)
On the Think Concrete website, there's loads of info about how concrete lasts longer and saves money. But the question on my mind is, "Which is better for the environment?"
A life cycle assessment comparing the environmental impacts of asphalt and steel-reinforced concrete was completed in 1998. It showed that while producing asphalt required more energy input, concrete required more ore and fertilizer inputs, and gave off more toxic emissions. On the other hand, asphalt was associated with higher levels of hazardous waste generation and management needs. The authors concluded that over the life of each material, the environmental impacts were roughly equal, but they also mentioned that asphalt was recycled more often than concrete, potentially turning the sustainability tide in its favor.
However, two separate studies have shown that concrete provides a better driving surface, decreasing the fuel needed to move a car down the road and thereby its emissions. (Both of the studies were completed in cooperation with cement associations, so throw some grains of salt in there). But there are other examples of concrete's environmental benefits.
And that's not all--there are some great innovations afoot with concrete. Some researchers are working to make cement with carbon absorbing properties, while others have found ways to make flexible concrete that heals itself, reducing the need for new materials and increasing safety.
Of course, there's also the pie-in-the-sky option: solar highways.