Concrete or asphalt? Urban planners and roadway engineers have been asking this question for decades. Depending on the specific needs of a community, both can be wonderful options.
Deciding between pervious concrete and porous asphalt can be a more difficult task. The key points to consider are initial and long-term costs, durability and maintenance. Each product shines in various areas. Despite its higher installation cost, pervious concrete’s greater durability makes it a better long-term option than porous asphalt.
Durability: Studies show that concrete typically lasts a decade or longer than asphalt before repairs are needed.
Much more than concrete, asphalt is susceptible to raveling, or breakdown of the material. The Florida Department of Transportation conducted long-term tests of various roadway materials, concluding that while pervious concrete was a great option, porous asphalt was not, due to a high level of raveling.
Heat Retention: Asphalt retains more heat than concrete, and that heat causes asphalt to break down. And porous asphalt is even worse than standard asphalt. A study conducted by the National Center of Excellence at Arizona State University found that porous asphalt exhibited higher daytime temperatures than even traditional asphalt. Pervious concrete, on the other hand, actually has been shown to be cooler.
The University of New Hampshire’s Stormwater Center notes that pervious concrete has reduced daytime temperatures, thus minimizing the Urban Heat Island effect. The same is not true of porous asphalt.
Cost: Both pervious concrete and porous asphalt cost roughly 20 percent more to install than their traditional counterparts, with concrete costing slightly more to install than asphalt.
One reason for the higher installation cost of pervious concrete is that the concrete is laid thicker. In typical applications, pervious concrete is laid at a thickness of 6 inches, compared to 3 inches for porous asphalt.
Maintenance: Porous surfaces, whether concrete or asphalt, require different maintenance than standard surfaces. The UNH recommends sweeping and pressure-washing and quarterly vacuuming of both types of surfaces, in addition to regular visual inspections. Standard concrete requires much less maintenance than standard asphalt, but there isn’t a huge difference between the pervious concrete and porous asphalt in regard to maintenance.
Ready to talk to local experts about the benefits of installing pervious concrete in NW Washington? Contact Custom Concrete Contracting in Bellingham, WA. They employ NRMCA certified pervious installers & technicians.