Experimental evaluation of fatigue resistance of asphalt mixtures containing waste elastomeric polymers

Abstract

Abstract This study concerning the asphalt mixture fatigue life, affected by the addition of waste elastomeric polymers obtained from polymer production process. Since the use of polymers is economically costly, and also there are some by-products in polymer production process, considering recycled polymers and waste of polymers is important in terms of environmental clean-up. Investigation of fatigue characteristics of HMA mixtures containing waste of elastomeric polymers and their comparison with unmodified mixtures are the main objectives of this research. In addition, different fatigue analysis approaches were evaluated in order to figure out the most precise results. Fatigue resistance of hot-mix asphalt (HMA) modified by elastomeric polymers such as SBR and PBR and the waste of their production process, was studied by performing four-point bending (4\u202fPB) test and indirect tensile fatigue test (ITFT) based on conventional and energy approaches. As far as the technical aspects are concerned, the traditional method based on 50% reduction in initial stiffness is not suitable enough to be employed for calculating fatigue life, because this method underestimates the fatigue life of polymer modified mixtures and leads to high variations among the responses. Therefore, two alternative fatigue analyses were conducted: The Ratio of Dissipated Energy Change method and the Energy Ratio method. Both these methods provided a more detailed comparison between the fatigue life of these mixtures. As the results shows, fatigue life of mixes modified by the waste of polymers, is significantly higher than unmodified mixes and considerably close to mixes including \u200c\u200coriginal polymers.