Chemical and physical aging in asphalt binders

This thesis documents and discusses the result of a study on the chemical and physical aging of straight, oxidized and polymer-modified asphalt binders used for road paving applications.; The main finding of this part of the work was that the currently adopted laboratory aging method, 85 minutes in a rolling thin film oven at 163°C followed by 20 hours in a pressure aging vessel at 100°C was inadequate for simulating the generally more severe aging that occurs over eight years of in-service conditions.; Fracture and rheological tests were conducted to study the effect of chemical and physical aging on performance-related properties. Fracture toughness and fracture energy at cold temperatures as well as warmer brittle-to-ductile transition temperature in fracture energy were used to measure to what extent the AASHTO aging protocol is incapable of producing materials representative of field-aged asphalt. The main finding of this part of the work was that the laboratory specification grading methods do a relatively poor job of predicting the performance related properties of asphalt binders at low temperatures due to the effects of physical aging. (Abstract shortened by UMI.)...