Rheology evaluations of WMA binders using ultraviolet and PAV aging procedures

• Asphalt binder can be oxidized under thermal and/or ultraviolet radiation conditions.
• Rheology of WMA binders after long term UV or PAV aging procedures was studied.
• UV and PAV aging behaviors are significantly affected by the binder source and grade.
• WMA additives generally have no influences on rheology of UV and PAV aged binders.
• UV aging procedure is effective in investigating rheological properties of WMA binders.

Oxidation of an asphalt binder affects the long term performance of an asphalt pavement, especially under thermal and/or ultraviolet (UV) radiation conditions. The objective of this study is to investigate the rheological behaviors of various WMA binders after long term UV aging and conventional PAV aging procedures. The following rheological properties were tested and evaluated in this study: complex shear modulus, phase angle, elastic modulus, viscous modulus at an intermediate service temperature, and deflection, stiffness, and m-value at a low temperature. The experimental design included four asphalt binder sources (two grades); four WMA additives and control. Two aging methods of UV and PAV aging were utilized and a total of 40 binders were tested and evaluated. The test results indicated that UV and PAV aging procedures are significantly affected by asphalt binder source and grade. In addition, WMA additives generally have no influences on rheological properties of UV and PAV aged binders. Moreover, the differences in deflection, creep stiffness, and m-values of UV and PAV aged binders are generally not affected by their grade, source and WMA additives. Therefore, UV aging procedure used in this study may be an effective method in investigating rheological characteristics of WMA binder after a long term aging process.