CONCEPTS AND PRACTICES FOR CONSIDERING GA AIRPORT PAVEMENT PERFORMANCE AND LONGEVITY. FINAL REPORT

This study examines Illinois Department of Transportation - Division of Aeronautics (IDOT-DOA) General Aviation (GA) airport pavement performance and the impact that load, climate, and materials/construction factors have on the formation and propagation of pavement distress and evaluates the adequacy and efficacy of current GA airport pavement design and construction practices. The research approach incorporated the review of construction specifications and records, an analysis of statewide climatic factors and their influence on pavement material behavior, state-of-the-art structural and materials modeling and testing, and the analysis of pavement performance and distress data collected during the IDOT-DOA biennial pavement distress inspections. IDOT-DOA pavement inventory and distress data were used to establish a relational pavement performance data base containing 195 non-rehabilitated pavement sections. The most significant findings are: (a) Load (as evaluated by the relative amount of Beechcraft King Air B200 traffic) was not a major distress formation/propagation factor. (b) Asphalt Concrete Pavements (ACP): Longitudinal and transverse cracking and paving lane cracking are the two most prevalent distress types. Illinois GA ACP sections are generally structurally adequate for typical GA loading. (c) Portland Cement Concrete Pavements (PCCP): Commonly occurring PCCP distresses include corner breaking, corner and joint spalling, D-cracking, joint seal damage, and longitudinal, transverse, and diagonal cracking. The most important factor influencing PCCP distress formation and propagation is slab size. Larger slabs have considerably higher distress occurrences and severities than smaller slabs. For normal GA loading conditions, both 6-in. and 5-in. (15.24-cm and 12.70-cm) thick PCCP are structurally adequate. The structural adequacy of a 4-in. (10.16-cm) thick PCCP is questionable. The following specific recommendations are offered: (a) The effects of the recently modified AC specifications (P-201 and P-401), pertaining to the construction of paving lane joints, should be monitored. (b) Current AC mixture design practices should be evaluated. The AC mixtures have "checked" in numerous GA projects. The use of SHRP asphalt cement binder specifications and Level 1 mix design procedures, featuring the use of the SHRP gyratory compactor, should be thoroughly evaluated for potential use. (c) The advantages/disadvantages of various PCCP slab sizes up to 15 ft (4.57 m) in should be further investigated. (d) A DESIGN CATALOG approach should be considered to standardize Illinois GA ACP and PCCP design procedures. Mechanistic-empirical design approaches can be utilized to design pavement structures for Illinois climatic conditions and commonly used materials. The catalog can be arranged according to climatic zone, traffic loading, and subgrade strength/stiffness properties. A number of alternative pavement designs would be presented for a given set of design conditions.