Since 2011, the FAA has collected data in support of extending airport pavement life on 28 runways at 22 U.S. airports. The data cover 17 of the 30 airports designated large hubs in 2017, as well as 3 medium hub and 2 small hub airports.
Design and as-built data have been collected for all runways studied, with historical traffic and friction records collected as available. Additional detailed field data, including Pavement Condition Index (PCI) distress surveys, Heavy Weight Deflectometer (HWD) testing, and profile, groove, and texture measurements, were collected from 12 of the 28 runways. Core samples and soil borings were also collected for characterization by FAA’s NextGen Materials Testing Laboratory.
Data collected under the Extended Airport Pavement Life project are stored in a database to facilitate data analysis and model development. This database has all the features of FAA PAVEAIR, FAA’s online pavement management system, but in addition, has links to remotely maintained databases containing detailed runway usage (traffic) and weather data.
The FAA is using real-world data to identify key performance trends and develop improved pavement life prediction models—models which are expected to form a comprehensive, and lasting, foundation for airfield pavements with cost-effective service lives.
What is life?
Current pavement design procedures equate “pavement life” to “structural life.” Structural life is defined by the number of aircraft passes causing a specific part of the pavement structure to fail in fatigue. While this definition supports an acceptable model for 20-year pavement design, in order to meet an enhanced standard of up to 40 years, the aviation industry will need to rethink its meaning of life.
Pavement design for the long term (greater than 20 years) must go beyond traditional analysis to consider how functional failures drive the decision to rebuild pavements.
The major rehabilitation triggers are Profile roughness (smooth ride), Foreign object debris (FOD) risk, and Low friction (skid resistance).
The FAA’s working definition for extended pavement life begins with Serviceability Level (SL), a function of a pavement’s ability to prevent roughness and FOD and provide adequate skid resistance. Intervention is required when either total SL, or partial SL based on one or more triggers, falls below a certain level.
Pavement life ends when reconstruction costs less than any other intervention capable of raising the SL above its minimum acceptable level for 10 years.