Dissipated energy approach for the fatigue evaluation of RAP asphalt mixtures

The results are discussed of a laboratory investigation on the fatigue resistance of Base Courses Asphalt (BCA) mixes, for road pavements, evaluated by means of the four-point bending test. The experimental analy-sis was performed on bituminous mixtures with Reclaimed Asphalt Pavement (RAP), up to 40% by weight of the aggregate. Both conventional and polymer modified bitumen was used in the investigation. The mix de-sign was based on volumetric (gyratory) and indirect tensile tests, on both wet and dry samples. The fatigue behaviour was evaluated at 20°C and 10 Hz, under strain control mode, by means of the conventional ap-proach, based on the reduction in the initial stiffness modulus, as well as using a dissipated energy method fo-cused on the Plateau Value concept. Between the different approaches used for the fatigue data analysis, it has been verified a qualitative consistency in the mixtures ranking, with a higher fatigue resistance presented by the polymer modified mixtures produced with RAP aggregates.