ABSTRACT
ABSTRACT: This paper describes the Israel Airports Authority’s (IAA’s) experience with airport-pavement bearing-capacity evaluation through the Pavement Classification Number (PCN) system. Various technical studies around the world indicate that pavement-surface deflections can be considered a predictor of pavement life. Therefore, impact-stiffness modulus values, defined as the ratio of the Falling-Weight Deflectometer’s (FWD’s) impact load to its consequent central deflection, can be used to evaluate the PCN of a particular flexible pavement. To recall, the PCN numerical value is determined from the allowable load rating (i.e., bearing strength) of the pavement. The latter may be calculated by applying the principles contained in ICAO Doc-9157-AN/901, Part 3-Pavements. In determining the allowable load rating, such factors as frequency of operation and permissible stress levels should be taken into account. Once the allowable load is established, the PCN value is determined by converting the rating to a standard relative number. For the present study, use is made of the old Dynamic Stiffness Modulus (DSM) procedure developed by the USCOE; this procedure is correlated with various FWD measurements conducted on four major runways or taxiways in Israel, together with in-situ borings. The results obtained were also checked against the relevant results made available from the full-scale trafficking tests conducted by the FAA at the National Airport Pavement Test Facility (NAPTF) in Atlantic City, New Jersey. Finally, the paper concludes with a recommendation as to the use of impact-stiffness modulus outputs from FWD measurements in order to determine the PCN of a flexile pavement directly and on the basis of local experience.
