this paper presents the effects of different amounts of reclaimed asphalt on fatigue life of asphalt mixtures. central composite method was used to design of experiments based on response surface method (rsm). binder type (pen 60/70 and pen 85/100), reclaimed asphalt pavement (rap) content (25, 50 and 75%) and loading strain (150, 250 and 350 micro strain) were selected as independent variables...