| The term, “High Temperature Fatigue” has long been identified in mechanical engineering as an important phenomenon that limits the life of metallic components. Asphalt pavement routinely encounters high temperatures in typical California climate regions, yet there has been little study of this phenomenon in the field of asphalt concrete. In this thesis, the effect on fatigue performance of high temperatures (30°C–40°C) in conjunction with trafficking has been studied by placing an aluminum plate under the conventional four-point fatigue test setup and bending the beam upward so as to prevent temperature-induced creep during the test. Thereafter, a dynamic and recursive approach, namely the Weibull dynamic approach, has been used to relate the accelerated laboratory fatigue tests on asphalt concrete to the predicted long term fatigue performance (crack initiation) of in situ pavements.; For crack initiation, the Weibull stochastic process was found to successfully describe the fatigue damage process, a process of stiffness deterioration, under any temperature or test conditions. Furthermore, the widely used Weibull proportional hazards model of survival analysis was recommended as a tool to integrate tests performed under various conditions of strain, temperature, and material variables, including the high temperature fatigue tests and conventional fatigue tests, into a single regression equation. This equation was used as a tool to assess the fatigue damage. A dynamic and recursive fatigue simulation program was developed using the Weibull approach and a layered-elastic theory subroutine to calculate the tensile strain. The Weibull accelerated failure time model was also used to estimate a correction factor to account for the inherent difference of boundary conditions between laboratory test results and in situ fatigue performance.; To verify the Weibull dynamic approach, the Federal Highway Administration (FHWA) sponsored “WesTrack” full-scale accelerated pavement testing project provided a complete and valuable data set containing not only information on various mixes, traffic and wander, pavement temperatures, and laboratory test results, but also the condition survey of fatigue performance. The computer simulation results were compared with the WesTrack condition survey results and validated the feasibility of the Weibull dynamic approach as applied to field fatigue performance prediction. |
