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The Practical Application and Economic and Environmental
Benefits of Pervious Concrete
INTRODUCTION
Pervious concrete pavement is one of the leading materials used by the concrete industry in effecting significant “Green” industry practices and is recognized as a Best Management Practice by the U.S. Environmental Protection Agency (EPA) for providing pollution control, storm water management and sustainable development. The increased interest in pervious concrete is due to those benefits in storm water management and sustainable development. This paper will provide technical information on the application, mixture design and construction methods of pervious concrete. It will also discuss many of the environmental and economic benefits of using pervious concrete.
WHAT IS PERVIOUS CONCRETE?
Pervious concrete is a zero-slump, open-graded material consisting of hydraulic cement, coarse aggregate, admixtures and water. Because pervious concrete contains little or no fine aggregates such as sand, it is sometimes referred to as “no-fines” concrete. When the cement and water are combined, it forms a paste that binds the coarse aggregate together in a hardened product with connected pores that allow water to pass through easily. The pores can range from 0.08 to 0.32 inches (2 to 8 mm), and the void content usually ranges from 15% to 25% with compressive strengths of 400 to 4000 psi (2.8 to 28 MPa). However, strengths of 600 psi to 1500 psa (2.8 to 10 MPa) are more common. Many of the void spaces are interconnected, forming channels that let water and air pass through the pavement. The draining rate of pervious concrete pavement will vary with aggregate size and density of the mixture, but will generally fall within the range of 2 to 18 gallons/minute/foot2 (81 to 730 liters/minute/m2). The density and flow rate depends on the properties and proportions of the materials used. Therefore, mix designs must take into account the
The Practical Application and Economic and Environmental
Benefits of Pervious Concrete
INTRODUCTION
Pervious concrete pavement is one of the leading materials used by the concrete industry in effecting significant “Green” industry practices and is recognized as a Best Management Practice by the U.S. Environmental Protection Agency (EPA) for providing pollution control, storm water management and sustainable development. The increased interest in pervious concrete is due to those benefits in storm water management and sustainable development. This paper will provide technical information on the application, mixture design and construction methods of pervious concrete. It will also discuss many of the environmental and economic benefits of using pervious concrete.
WHAT IS PERVIOUS CONCRETE?
Pervious concrete is a zero-slump, open-graded material consisting of hydraulic cement, coarse aggregate, admixtures and water. Because pervious concrete contains little or no fine aggregates such as sand, it is sometimes referred to as “no-fines” concrete. When the cement and water are combined, it forms a paste that binds the coarse aggregate together in a hardened product with connected pores that allow water to pass through easily. The pores can range from 0.08 to 0.32 inches (2 to 8 mm), and the void content usually ranges from 15% to 25% with compressive strengths of 400 to 4000 psi (2.8 to 28 MPa). However, strengths of 600 psi to 1500 psa (2.8 to 10 MPa) are more common. Many of the void spaces are interconnected, forming channels that let water and air pass through the pavement. The draining rate of pervious concrete pavement will vary with aggregate size and density of the mixture, but will generally fall within the range of 2 to 18 gallons/minute/foot2 (81 to 730 liters/minute/m2). The density and flow rate depends on the properties and proportions of the materials used. Therefore, mix designs must take into account the
References: “Asphalt Price Increases Boost Concrete Pavement Opportunities.” NRMCA E-News. 21 July 2008. www.nrmca.org Fisher, Dale, President and CEO, PCI Systems, LLC. Telephone and email correspondence. July 2008. National Ready Mixed Concrete Association (NRMCA), Text Reference for “Pervious Concrete Contractor Certification,” NRMCA Publication #2PPCRT, Silver Spring, Maryland, February 2007. Obla, K., “Pervious Concrete for Sustainable Development,” Recent Advances in Concrete Technology, Washington, DC. September 2007. Palmer, Jr., William D. “Concrete that Drains,” Concrete Construction, Volume 5, Number 6, June 2005. pg. 44-45. Pervious Concrete: “When it Rains it Drains,” www.perviouspavement.org Torvinen, Jeff W., Engineer, Somero Enterprises, Inc. Telephone and email correspondence. July 2008.