The Performance of Asphalt - Pt.1
Posted by Jesse Willoughby on Fri, Apr 24, 2009 @ 07:03 AM
Roads that don't wear outOne of the keys to sustainability is long life. With Perpetual Pavements, asphalt pavements have an extremely long lifespan.
A Perpetual Pavement is constructed so that distress occurs in the top layer only. The only rehabilitation required is removal of the surface and resurfacing with an asphalt overlay. Using current pavement technologies, this can be done on an infrequent basis-every 15 to 20 years. The reclaimed material is then recycled. Perpetual Pavement is the ultimate in sustainable design and construction.
While the Perpetual Pavement name is relatively new, the concept is not. In fact, more than 35 pavements have received the Perpetual Pavement Award since 2001. These award-winning roads, streets, highways, and airport runways have been in place for at least 35 years, with a minimum of maintenance and no full-depth reconstruction.
Rubblization
When concrete pavements reach the end of their useful life, they must undergo expensive, time-consuming rehabilitation or be completely removed and replaced. This process squanders precious natural resources, in addition to inconveniencing the traveling public. Prolonged road closures also lead to congestion, which consumes energy and produces excess emissions. Asphalt's answer is a sustainable process called rubblization, in which the concrete pavement is left in place, "rubblized" (fractured), and used as the base for a new Perpetual Pavement.
In addition to the environmental advantages, cost savings can be significant. The rubblization process is much faster than the remove-and-replace option. It can also be accomplished through temporary lane closures, without the necessity for traffic to be detoured onto parallel routes.
Public safety
Smooth asphalt roads give vehicle tires superior contact with the road.
One type of asphalt surface, known as open-graded friction course, allows rainwater to drain through the surface layer and off to the sides, reducing the amount of splash and spray kicked up by vehicles.