Development of a Damage-Based Phenomenological Fatigue Model for Asphalt Pavements

Abstract

Bottom-up fatigue cracking is one of the major distresses for asphalt pavements. Accurate prediction of fatigue cracking for asphalt pavement is of paramount importance for a cost-effective pavement design. A fatigue model based on mechanistic-empirical pavement design is modified from an Asphalt Institute model. However, there are some controversies about the effectiveness of the mechanistic-empirical pavement design fatigue model. The major concern exists on the use of dynamic modulus as a key parameter and there is no damage property of asphaltic mix to predict fatigue, which is induced by damage to the material. This study developed a damage-based phenomenological fatigue model. The pavements at the Federal Highway Administration’s Accelerated Loading Facility (ALF) were used to test the effectiveness of existing models, including the mechanistic-empirical pavement design fatigue model, and validity of the damage-based fatigue model. The data used in this study included dynamic modulus, critical strain-energy density of hot-mix asphalt (HMA), tensile strain at the bottom of HMA layer, and the fatigue life of ALF pavements. It was found that the damage-based model significantly improved the accuracy of the prediction, when compared with the mechanistic-empirical pavement design fatigue model and other conventional models.