New laboratory and field relationships between asphalt mix variables and their fatigue life and permanent deformation characteristics are presented and discussed. It is shown that the laboratory fatigue life and plastic deformation of laboratory specimens can be predicted from a knowledge of several parameters pertaining to the compacted asphalt mix, magnitude of the applied load, and test temperature. Predictions of the fatigue life and rut depth of asphalt pavementsrequire, in addition to the above parameters, the compressive and tensile strains of the asphalt course, as well as the moduli of the different pavement layers. During the course of the laboratory investigation, a new indirect tensile test apparatus was designed, fabricated, and used to conduct cyclic load indirect tensile tests using marshall-type specimens and various asphalt concrete mixes. The test results indicate that the indirect tensile test can be used to characterize the fatigue life of asphalt concrete mixes. This paper appears in transportation research record no. 1227, Rigid and flexible pavement design and analysis: unbound granular materials, tire pressures, backcalculation, and design methods.
Samenvatting