Philip Kresge, National Ready Mixed Concrete Association

Pervious concrete is not new. Studies show that pervious concrete was first used in 1852. However, pervious concrete is enjoying a new popularity, to the point that pervious concrete pavement is the hottest topic in today's sustainable development design community.

As a senior director of national resources for the National Ready Mixed Concrete Association and a member of the NRMCA's National Accounts promotion program, I have given numerous presentations on pervious concrete. These seminars have been attended by architects, engineers and specifiers as well as representatives from local and state regulatory agencies. Nine out of 10 requests I receive are for information regarding some aspect of pervious concrete.

While nearly everyone understands the concept of pervious concrete and its contributions to reduction of stormwater runoff and pollutant removal, I am continually asked the following questions: "Where has pervious concrete been used? How does pervious concrete hold up to freezing and thawing? What about clogging? Does my state's environmental regulatory agency accept/approve pervious concrete for stormwater management?"

In short, the answers are, "everywhere, very well, no problem and depends." But you deserve better answers than these, so let me address each of them separately.

Where has pervious concrete been used?
Pervious concrete pavements have been identified dating back to 1985. There may be older existing projects still waiting to be identified, though. The confusion is that back then the product was known by such names as no-fines concrete, enhanced porosity concrete (EPC) and even "popcorn concrete." The NRMCA is in the process of compiling a national database of pervious concrete projects.