Evaluation of the Effect of PBR Production Wastes in Bitumen on Fatigue Resistance of Asphalt Concrete Mixtures

There are different factors which play important role in cracks’ formation and propagation of asphalt layers, and also fatigue cracks are one of the most frequent damages in roads and highways. Two of these most important factors are traffic load and temperature effects. In order to introduce new eco-friendly products and reduce contaminants, and since the use of polymers is economically costly, in this paper polymer's waste are utilized as bitumen additives. Also, the decomposition or destruction of petrochemical processes’ products take many years, and their release and burial cause environmental degradation. This study, evaluates the fatigue resistance of hot-mix asphalt (HMA) modified by waste elastomeric polymers. Four-point bending (4PB) tests at constant strain mode at a temperature of 20℃ and at three strain levels were performed. In addition, indirect tensile fatigue tests (ITFT) were performed at 15 and 25 ℃ and at two stress levels. The both tests' results are compared. In addition, fatigue life analysis tests and approaches are compared based on conventional and energy approaches. According to results obtained based on 50% reduction in initial stiffness method, the Energy Ratio method and the Ratio of Dissipated Energy Change method, fatigue life of modified mixes is significantly higher than unmodified ones. Furthermore, the obtained results were analyzed for statistical comparison.