The temperature effects in aging index of asphalt during UV aging process

Abstract

With increasing global warming and the corresponding increase in the emissions of Ultra Violet radiations, the effect of UV radiations on the aging of asphalt gained more attention from researchers. However, the Ultra Violet (UV) aging methods used by different researchers are quite different. And even the UV aging working temperatures were not the same. Most researchers simulated the UV aging at temperature ranging from 30°C to 80°C. So temperature (from 30°C to 80°C) effects in UV aging were investigated to find out whether the temperature effects can be ignored. Three temperatures (30°C, 50°C and 70°C) were carried out during UV aging procedure with other UV aging conditions kept the same. The softening point and penetration results indicate that temperature could only slightly influence the UV aging under 50°C condition. The aging index of asphalt and deterioration of SBS modified asphalt increase dramatically at UV aging temperature condition of 70°C. The temperature sweep tests performed by Dynamic Shear Rheometer (DSR) show the same tendency as softening point and penetration results. Fourier Transform infrared spectroscopy (FTIR) and mass change tests were carried out as well in this research. Oxidation degree of asphalt and deterioration degree of SBS modifier both increase at 70°C UV aging temperature according to FTIR results. The mass changes results show that mass reducing ratios under UV condition are almost four times higher than heating condition for base asphalt and thirteen times for SBS modified asphalt. So the temperature effects on UV aging cannot be ignored and the suggesting UV aging temperature is under 50°C.