Effect of aging conditions on the fatigue behavior of hot and warm mix asphalt

Abstract

The aging process has a significant effect on the mechanical properties of asphalt mixtures, especially on fatigue parameter. Many approaches have been suggested to better understanding of the fatigue behavior of asphalt mixes. However, in many of these cases, the effects of aging are not considered. In this study, investigations were conducted to more accurately predict the fatigue life of asphalt mixes, independent of their ages. In this regard, the responses of the existing fatigue models in a wider range of asphalt mixtures were validated. For this purpose, hot and warm asphalt mixtures were used in both aged and unaged conditions. For the production of warm mixtures, Sasobit and RheoFalt were used as modifier additives. Indirect tension (IDT) test, resilient modulus and four-point bending fatigue beam test were performed separately WMA and HMA specimens. The results indicated that in all specimens, the aging of the asphalt mixture was always accompanied by increasing fracture energy and failure resistance. In addition, it was also found that those fatigue models that were based on simple performance tests failed to well predict the fatigue life of mixtures independently of the type of compounds, aging and loading conditions. Eventually, validations indicated that the behavior of dissipated energy during repeated loading to failure, have a significant role to precisely characterize the fatigue behavior independent of their age.