Evaluation of fatigue resistance in asphalt surface layers containing reclaimed asphalt

This paper evaluates the fatigue resistance of surface layer stone mastic asphalt that incorporates reclaimed asphalt at quantities of 0%, 20% and 40%. The fatigue resistance was tested using a four point bending test. The inclusion of reclaimed asphalt in the mix resulted in the stiffness moduli of the mixes increasing with reclaimed asphalt content. The wide variation in stiffness moduli across the mixes tested meant the classical analysis method was unsuitable for calculating the fatigue life of the mixes. Two alternative fatigue analyses were successfully applied: the Ratio of Dissipated Energy Change-Plateau Value method and a comparative model method. Both these methods provided a better comparison of the fatigue life of these mixes. The difficulty, due to the wide variation in stiffness moduli across the mixes tested, in the evaluation of fatigue resistance of asphalt mixes containing reclaimed asphalt is also highlighted.