A long-term ultraviolet aging effect on rheology of WMA binders

Abstract

Asphalt binder is generally easy to age in the field, especially under thermal and/or ultraviolet (UV) radiation conditions. Current asphalt performance evaluation system gives limited consideration to UV aging, especially, as using warm mix asphalt (WMA) technologies. The objective of this study is to investigate the influence of long-term UV aging on rheology of various WMA binders. The following rheological properties were tested and evaluated in this study: viscous flow, performance grade, creep and creep recovery, amplitude and frequency sweep tests. The experimental design included four asphalt binder sources and two grades; four WMA additives (Cecabase-RT, Evotherm, Rediset, and Sasobit) and control. A total of 20 binders were tested. The test results indicated that a UV aging procedure generally had obvious effect on the complex modulus and phase angle values of various UV aged WMA binders. Their viscosity values were generally different since the WMA additive or binder source played a key role. Moreover, creep and creep recovery generally showed a similar trend for various WMA binders. Similarly, the amplitude and frequency sweep values exhibited a similar trend for various WMA binders but these values were different for various binder sources and grades. Therefore, it is necessary to explore the rheological properties of WMA binders after a long term UV aging procedure in the lab.