Pervious Concrete Pavement
Pervious concrete pavement is a unique and effective means to address important environmental issues and support green, sustainable growth. By capturing stormwater and allowing it to seep into the ground, porous concrete is instrumental in recharging groundwater, reducing stormwater runoff, and meeting U.S. Environmental Protection Agency (EPA) stormwater regulations. In fact, the use of pervious concrete is among the Best Management Practices (BMPs) recommended by the EPA—and by other agencies and geotechnical engineers across the country—for the management of stormwater runoff on a regional and local basis. This pavement technology creates more efficient land use by eliminating the need for retention ponds, swales, and other stormwater management devices. In doing so, pervious concrete has the ability to lower overall project costs on a first-cost basis.
In pervious concrete, carefully controlled amounts of water and cementitious materials are 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. Using sufficient paste to coat and bind the aggregate particles together creates a system of highly permeable, interconnected voids that drains quickly. Typically, between 15% and 25% voids are achieved in the hardened concrete, and flow rates for water through pervious concrete are typically around 480 in./hr (which is 5 gal/ft²/ min ), although they can be much higher. Both the low mortar content and high porosity also reduce strength compared to conventional concrete mixtures, but sufficient strength for many applications is readily achieved.
While pervious concrete can be used for a surprising number of applications, its primary use is in pavement. Pervious cocrete is also referred to as porous concrete, permeable concrete, no-fines concrete, gap-graded concrete, and enhanced-porosity concrete.
Since 1930, the National Ready Mixed Concrete Association (NRMCA) has provided ready mixed concrete producers and the construction industry with accurate information and cutting-edge research and development support for the realization of concrete’s ever-advancing capabilities. In 2003, NRMCA created the Concrete Resource Team to directly support users of concrete by helping to implement a variety of innovative, sustainable solutions, including the utilization of concrete to gain LEED certification and assistance in developing pervious concrete stormwater mitigation systems.