Fatigue Properties of Aged Porous Asphalt Mixtures with an Epoxy Asphalt Binder

Abstract

Porous asphalt pavement has been used for multiple purposes, but its large porosity makes it easy to age by long-term weathering conditions; this causes its premature failure through raveling, fatigue, and so forth. This study explored the fatigue performance of aged porous asphalt mixtures produced with epoxy asphalt binders. Gradations of three porous asphalt mixtures were first designed in the laboratory: (1) a porous asphalt mixture 13 with an epoxy asphalt binder (EPA-13); (2) a porous asphalt mixture 13 with a high-viscosity asphalt binder (HPA-13) as a control; and (3) a dense-graded asphalt mixture 13 with a high-viscosity asphalt binder (HDA-13) as another control. Then, fatigue tests were conducted under different strain levels on porous asphalt mixture samples before and after aging. In addition, the effect of loading sequence on fatigue was examined for samples under two-stage continuous loading conditions. The results showed the following three things. First, the use of epoxy asphalt binder can tremendously improve the fatigue resistance of porous mixtures. the fatigue life of EPA-13 was 2.0 to 4.5 times greater than that of HPA-13, depending on the strain level. Second, after long-term aging, the fatigue life of the EPA-13 subjected long-term aging decreased by 82.3%. The retention rate of the initial modulus was about 50%. The fatigue life of the weathered EPA-13 was still much better than that of the weathered HPA-13. Third, loading sequence had a remarkable influence on the damage accumulation of all mixtures discussed.