Engineering Term of the Month Permeable Pavement
Permeable pavements are a sustainable alternative to traditional impervious surfaces. Unlike conventional pavements, they allow stormwater to infiltrate through the surface into the ground below, helping to manage runoff at the source. Common types include porous asphalt, pervious concrete, and permeable interlocking concrete pavement. These systems intercept, filter, evaporate, and infiltrate stormwater, reducing surface ponding and local flooding.
Permeable pavement systems typically include both surface and subsurface layers, tailored to the specific application. The surface layer features a more open void structure to facilitate infiltration. Subsurface components may include: choker course; filter course or base reservoir; subbase reservoir, optional underdrain and / or geotextile layer; subgrade; and optional liner.
The primary maintenance issue is clogging, which reduces infiltration capacity. Other concerns include:
• Structural capacity
• Prolonged saturation of roadway surfaces
• Rutting
• Freeze-thaw cycles
• Constructability
• Long-term durability
Sources:
• Tech Brief, Use of Permeable Pavements, FHWA-HIF-23-076, 2023
• Stormwater Best Management Practice, Permeable Pavements, United States Environmental Protection Agency, EPA-832-F-21-031W, December 2021
• Tech Brief, Use of Permeable Pavements, FHWA-HIF-23-076, 2023