Using damage theory to analyze fatigue of asphalt mixtures on flexural tests

Federal agencies and research centers around the world are studying and producing laboratory tests and procedures, as well predicting models, trying to obtain better insights related to fatigue in hot mix asphalt. The increasing interest in the development of fully mechanistic models for pavement design is changing the guidelines for newer studies. Even with climatic and traffic information as sources of empirical but necessary inputs, it is important to assess how damage increases and calculate damage properties of asphalt concrete toward the next generations of mechanistic design tools. This work presents an extensive analysis of fatigue test results using different asphalt concretes. The linear viscoelastic characterization of all mixtures was done by frequency sweep tests (E∗). An approximate interconversion process was also used to find additional viscoelastic properties. Fatigue data were treated using the continuum damage approach, and damage parameters were obtained. Furthermore, a relationship was evaluated among viscoelastic properties and damage parameters, which might be useful for fatigue characterization.