Ultrviolet (UV) aging and low temperature are two main factors which result in premature damages of asphalt pavements in Tibetan plateau, China. According to measured level of ultraviolet radiation, aging tests of asphalts with different contents of three anti-UV-aging agents, which include nano-TiO2, CeO2 and carbon black, are performed. Common indices, which include penetration and softening point, and SHRP indices of aged asphalts are evaluated. IR analysis has been taken for asphalt specimens with 0.8% carbon black which have been aged for different aging times (500h, 1000h and 1500h). By grey incidence analysis, optimal contents of anti-UV-aging agents are determined. Asphalt sulfide's effects on improving low-temperature performance and anti-aging performance are evaluated by DTT and thermal-oxygen aging test. These results show that, although nano-TiO2 and CeO2 are good UV absorbing and shielding agents, but they are also strong oxidants, aging of asphalts will be accelerated with excessive contents. Carbon black is a good anti-UV-aging agent, and its optimal content is about 0.8% of the asphalt weight. UV aging of asphalt mainly occurs in the early stage of aging, the longer aging time the severer aging of asphalt. Asphalt sulfide with suitable sulfur content can improve low-temperature performance and anti-aging performance of asphalt to some extent.
Abstract