MODELING OF TENSILE CREEP AND RECOVERY OF POLYMER MODIFIED ASPHALT BINDERS AT LOW TEMPERATURES

The creep and recovery of asphalt modified with Elvaloy 4170 and polyphosphoric acid were studied at low temperatures, by inductive phenomenological methods. Two models of the tensile compliance function were investigated. Both models were derived from the linear viscoelastic retardation spectra and successfully used for the description of the creep and recovery tests in the studied asphalt binders. Large effects due to oxidative aging in a rolling thin film oven were found from the recovered compliance function recorded in a bending beam rheometer at a temperature of - 20 degrees C. The studied compliance function models worked well at higher and lower temperatures in creep and recovery experiments on conventional and modified asphalt binders for both shear and tensile creep.