Guidance for Usage of Permeable Pavement at Airports (2017)

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1 Permeable pavement provides a stormwater management alternative that has seen increased interest in recent years. While there is fairly extensive documentation on the use of permeable pavements for vehicular and pedestrian applications, there is little informa- tion available related to their use at airports, particularly in areas used by aircraft. This study investigated the use of permeable pavements at airports and developed recommendations for future applications. There are numerous benefits provided by the use of permeable pavements, but there are also disadvantages that make their use not the right option for every potential application. These are addressed in detail later in the report. Some of the study’s findings are summarized as follows: • Based on survey responses, experience with permeable pavement at airports (airside and landside) is limited. There are relatively few airport permeable pavement projects, particularly for areas where aircraft operate. • Airside uses of permeable pavements include runway and taxiway shoulders, aprons, and service roads. Landside uses have primarily been for parking lots. • Where used in areas of aircraft operations, permeable pavements have been designed for infrequent, heavy aircraft and frequent, light aircraft. Thickness design has been performed with FAA’s FAARFIELD program (and LEDFAA, previously) and design methodology, as well as the AASHTO thickness design methodology. • Permeable pavement designs were not typically full-infiltration systems. Rather, the sys- tems were designed for other stormwater management needs, such as delaying the time of peak discharge or providing a paved surface that did not increase the impermeable area of the airport. • Materials selection plays a significant role in the performance of the pavement. For example, abrasion or raveling observed in some pavements appears to be attributed to mixtures that were different from current recommended industry guidance. • State standards have been primarily used for materials specifications. Modifications of Standards (MOSs) have not been pursued for FAA approval of nonstandard materials. • Permeability of the pavement can be maintained over time with routine maintenance (such as vacuum sweeping). • When considering the overall cost of storm drain systems or the need to purchase land for surface drainage facilities, permeable pavements can be cost-effective. Although some materials costs are greater for permeable pavement during initial construction, the overall cost comparison with a traditional system needs to be considered. • The airside projects have been constructed without the use of FAA funds. S u m m a r y Guidance for Usage of Permeable Pavement at Airports

2 Guidance for usage of Permeable Pavement at airports Based on the findings made during this study, the following observations can be made: • Permeable pavement can fill stormwater management needs at airports, including in areas with aircraft operations. • Sites for landside (or vehicular) applications should follow industry recommendations: parking lots, light- to medium-weight vehicle roadways, pedestrian facilities, and so on. • Sites for airside (or aircraft) applications can include frequent, light aircraft use and infrequent, heavy aircraft use. However, there is not a history of performance under aircraft loadings. As with all permeable pavement locations, the risk of spills needs to be considered. An MOS from the FAA would be required for the construction of permeable pavements using federal funds. • Pavement design using the FAA methodology and software has been performed, but the layer inputs need to be selected carefully. Future research would be needed to validate inputs and performance. • State standards and FAA specifications can be modified to provide durable permeable pavement materials. (Note: an MOS would be required.) • User awareness of what permeable pavement is, and establishing maintenance procedures, can provide long-term permeability.