A comprehensive review on the fatigue resistance of recycled asphalt materials: Influential factors, correlations and improvements

Cracking, mainly referring to fatigue damage, is one of the primary distress modes of asphalt pavement. The inquiry into the fatigue resistance of asphalt binders and mixtures are summarized in this paper, along with the affecting factors, the fatigue resistance correlations between binders and mixtures, and improved measurement. The influencing factors of fatigue performance for recycled asphalt pavement are divided into intrinsic, such as Reclaimed Asphalt Pavement (RAP) content, types of asphalt binder, and aggregate gradation, and external, such as rejuvenator, mixed additives, and temperature. The different fatigue evaluation methods and indices of binder and mixtures significantly affect the fatigue resistance correlations between binders and mixtures. The various binder properties and fatigue test conditions in binders and mixtures can cause a remarkable change in the fatigue performance correlations. Furthermore, adding softer virgin asphalt, rejuvenator, warm mixing agent, and optimizing the gradation of recycled mixtures are utilized to meet the fatigue behavior requirement in the engineering practice. From the perspective of the fatigue behavior of asphalt materials, this work provides light on the design of materials for environmentally friendly and long-life pavement, and recommends areas for future investigation that are pertinent to fatigue resistance of recycled asphalt pavement.