Chemo-rheological deterioration of bitumen due to UV ageing: correlations between accelerated UV ageing tests and 1-year outdoor exposure

Predicting the performance of asphalt roads after several years of service is complex due to multiple weather events that can contribute to road ageing. This study investigates the correlation between an accelerated ultraviolet (UV) ageing test and the ageing of polymer-modified binders after 1 year spent in outdoor conditions. The impact of natural ageing on several bituminous binders was investigated by rheological and chemical analyses. Plastomer-modified (ethylene vinyl acetate) bitumen seemed to be the most affected by environmental ageing as evaluated through rheological and chemical testing. Elastomer-modified (styrene butadiene styrene) bitumen appeared to be the most resistant to environmental ageing as expressed by non-load related cracking resistance and relaxation properties as well as low oxidation levels. The natural ageing test confirmed the results obtained via the accelerated UV ageing test considering the Glover-Rowe parameter (average R 2 = 0.89). The 30-day accelerated UV test was estimated to fasten natural ageing of conventional and plastomer-modified bitumen by more than 10 times and up to 5 times for elastomer-modified bitumen compared to long-term outdoor exposure. If used with a suitable weather dataset, accelerated UV ageing is a promising method to predict the environmental-related ageing of conventional unmodified bitumen; however, adjustments are required for polymer-modified binders. • Five different commercial PMBs were exposed to outdoor weathering for 1 year. • The same binders were exposed to accelerated UV ageing for 30 days in the laboratory. • A10E and A15E were less affected by natural ageing than S45R, C170 and A35P. • GR parameter was the most suitable test to correlate accelerated and outdoor UV ageing. • 1 year of outdoor ageing was reproduced by 26 days in a UV chamber for C170 bitumen.