Pervious concrete contains a carefully controlled amount of water and cementitious materials used to create a paste that forms a thick coating around aggregate particles. A pervious concrete mixture contains little or no sand, creating a substantial void content. It is this 15 – 25% void content that allows stormwater to flow through the pervious concrete, eventually returning the stormwater to the soil.

Pervious concrete is manufactured and delivered in the same way as conventional concrete.  However, the placing, handling and curing of pervious concrete differs from conventional concrete to such a degree that specialized certification has been designed for pervious contractors. This certification is available through the Illinois Ready Mixed Concrete Association.

Pervious concrete can solve environmentally dangerous stormwater runoff problems as well as offer developers an alternative to space costly retainage ponds. While designed and used most often for parking areas, pervious concrete has been placed for walkways, bike paths, flooring for greenhouses and for light-use roadways.

A stormwater system utilizing pervious concrete on the surface can keep contaminated water from reaching our rivers and streams by “treating” the water through the system and returning to the ground. The light color of concrete pavement absorbs less heat than darker pavements, and the voids in pervious help keep the pavement cooler.  Trees planted near parking lots and city sidewalks offer shade and produce a cooling effect in the area, further reducing heat island effects.

Engineers, architects and developers are increasingly specifying pervious concrete and its environmental advantages ensure that it will remain popular for the foreseeable future.