New structural design guide for porous asphalt offers ‘green infrastructure solution’

Updated Aug 8, 2018

Structural Design Guidelines for Porous Asphalt Pavements

A new publication provides guidelines for the structural design of permeable asphalt pavements using the AASHTO 93 Design Methodology

Porous asphalt pavements are considered a green infrastructure solution and provide the performance, ease of construction and functionality of traditional asphalt pavements but with a permeable structure that helps manage stormwater, according to the National Asphalt Pavement Association (NAPA).

Commonly used for parking lots and other light-duty applications, full-depth porous asphalt pavements are increasingly used on roadways to help “mitigate flooding hazards, reduce hardscape and improve sustainability,” a press release says.

To help ensure reliable performance under traffic, NAPA has published Structural Design Guidelines for Porous Asphalt Pavements.

“Often the design of porous asphalt pavements is focused on how well the pavement will handle water, not traffic,” says civil engineer Audrey Copeland, NAPA vice president for engineering, research and technology.

“For most parking lots and light-duty surfaces this may be a reasonable approach,” she says, “but as public agencies look to use full-depth porous asphalt pavements on roadways a traditional structural design methodology is needed.”

Design examples are included for full-depth porous asphalt pavement systems with and without an asphalt-treated permeable base, as well as a catalogue of required layer thicknesses for different traffic levels.

Written by Charles W. Schwartz, Ph.D., and Kevin D. Hall, Ph.D., P.E., with the support of the NAPA-SAPA Pavement Economics Committee’s Pavement Design Task Group, Structural Design Guidelines for Porous Asphalt Pavementsdiscusses the structural design procedure for porous asphalt and the required inputs using the AASHTO 93 design method.

“This new publication helps pavement designers and agencies apply the widely used and accepted AASHTO methodology to porous asphalt pavements,” Copeland says.

The book includes guidance on:

  • Determining structural design input values
  • Calculating minimum layer thicknesses
  • Limits on effective structural thickness.

Structural Design Guidelines for Porous Asphalt Pavements compliments the previously published Porous Asphalt Pavements for Stormwater Management: Design, Construction and Maintenance Guide. Both books are available as PDF downloads through the NAPA Online Store,