Influence of Asphalt Binder Oxidative Aging on Critical Thermal Cracking Characteristics of Asphalt Mixtures

摘要

The influence of oxidative aging of asphalt binders on the thermal cracking characteristics of asphalt mixtures was evaluated through analyses of thermo-volumetric (Coefficient of Thermal Contraction [CTCJ), thermo-viscoelastic (stiffness-temperature relationship), crack initiation and fracture, and damage characterization parameters. These properties were evaluated utilizing laboratory-prepared specimens aged for multiple durations in laboratory ovens. The thermo-viscoelastic characterization was founded upon the linear viscoelastic solution of thermally stressed mixture characterization determined though the Uniaxial Thermal Stress and Strain Test (UTSST). A critical aspect of the UTSST measurements was determined to be the crack initiation stress and temperature which was additionally supported by the Viscoelastic Continuum Damage (VECD) methodology. Validation of the evolution of the thermal cracking characteristics of the mixtures with aging was obtained through corresponding measurements of the core specimens from the nearly 20 year in-service WesTrack field sections.