Two-Stage Weibull Approach for Asphalt Concrete Fatigue Performance Prediction

摘要

This paper presents the two-stage Weibull phenomenologicalapproach to characterize the fatigue damage process of asphalt concretemixes for both the crack initiation and crack propagation phases. Foreach test, parameter estimation can be performed using the Lagrange-Newton algorithm. This algorithm can clearly identify the number ofrepetitions at which crack initiation and crack propagation are separated.A set of WesTrack tests was utilized as the demonstration example. TheWesTack mixes consisted of three gradations: fine, fine plus, and coarse.For each gradation, 12 beam tests were conducted at three temperatures(10, 20, and 30C) with various strain levels. After collecting all theinformation for the repetitions at which separation occurs for a series oftests, integrated Weibull-type regression equations can be obtained forcrack initiation and crack propagation. To correct the difference betweenin-situ and laboratory boundary conditions, correction factors for thetwo-stage Weibull approach are also discussed. Finally, with theintegrated regression equations and correction factors for crack initiationand crack propagation, the fatigue performance prediction of a WesTracksection was simulated with a “damage hardening” fatigue damageaccumulation mechanism. This two-stage Weibull approach appearspromising for fatigue performance prediction and use in recursiveanalysis, provided that the prediction results can be verified by morecomprehensive field data, especially the stiffness deterioration history offield pavements.