Laboratory Fatigue Models for Hot Mix Asphalt Modified with Waste Plastic Bottles

Fatigue cracks are considered as the main failures in bituminous layers of pavement. Hence, knowledge about the fatigue characteristics of these layers is important in design and evaluation of pavement. There is not enough information regarding to the fatigue properties of modified mixes with waste plastic bottles (PET). Indirect tensile stiffness and fatigue tests were performed at 5 and 20 °C. Different amounts of PET (2 to10% by weight of bitumen) were added to asphalt mixture in dry method. In this research in order to develope fatigue models for PET modified mixes. Based on obtained results the slope of correlated fatigue curves reduced upon reducing the testing temperature. At 210 microstrain level and above, the increasing in resilient modulus caused a reduction in fatigue life, whereas below 210 microstrain the reverse was true. Finally based on laborator y testing results distinct models were established for different boundary strain levels.