Ultra-violet (UV) aging for asphalt binder under controlled moisture and temperature conditions

Natural insolation is more severe to asphalt concrete (AC) pavements than standard laboratory aging procedures. However, it affects the asphalt binder until a limited AC depth. Understanding the impact of ultra-violet radiation (UVR) on asphalt binder oxidation could improve the simulation of near-surface asphalt binder aging and enable develop a relatively more realistic accelerated laboratory aging method. A repeatable method to irradiate asphalt binder with ultra-violet light requires mitigating the variability induced by different types of aggregates, moisture conditions, and temperatures. Thus, an accelerated aging procedure of asphalt binder utilizing UVR was developed. After initial trials proving the importance of sample thickness and rate of oxidation, a methodology was developed to age asphalt binder samples after optimizing sample thickness and the effect of temperature-UVR coupling. The methodology may be used to assess asphalt binders' susceptibility to UVR and select better additives to better control AC cracking related to binder brittleness.