CASE STUDY OF AN INNOVATIVE HIGH STABILITY ASPHALT MIX FOR HEAVY AIRCRAFT WHEEL LOADS

摘要

The paper describes the development and case study of an innovative solution, called the High Stability mix, for airfield pavement design. The High Stability mix provides improved resistance to permanent deformation of asphalt concrete pavements under heavy aircraft wheel loads. Development of the High Stability mix began in 1995 in response to permanent deformation and distortion in the surface layer of asphalt concrete taxiways at San Francisco International Airport (SFIA). Asphalt mixes on these taxiways fully met the Federal Aviation Administration (FAA) P-401 specifications for conventional mixes. However, stationary, stop-and-go, and slow movement of Boeing 747-400 wheel loads caused "dimples" on the pavement surface as well as ruts from turning movements on the taxiways. Mix design, construction, pavement loading history and results of laboratory studies showing deficiencies of the then-existing asphalt concrete mix is described. The development of enhancements to the FAA P-401 specification, evaluation of job mix formulas and recommended additional laboratory tests are discussed. The paper describes attributes of the High Stability mix, including the use of a stiffer binder, crushed aggregates, and increased air void content. Subsequent to construction of High Stability mix on the taxiways, pavement surface profile measurements and condition evaluations were recorded over a two-year period and are described in the paper. Results show superior long-term performance compared with previously used asphalt concrete mixes.