适应西藏高原环境的沥青抗紫外线老化试验研究

紫外线是导致西藏高原沥青路面早期损害的主要原因之一．根据实测的紫外线辐射水平，进行了不同掺量的3种纳米级抗紫外线老化剂（TiO2，CeO2和炭黑）的SBR沥青紫外线老化试验．针对老化后的沥青，进行了常规指标（TFOT后的针入度比、软化点）和SHRP指标的评价．针对已老化不同时间（500，1000和1500h）的、掺加0．8％炭黑的沥青，分别进行了红外光谱分析．采用灰色关联分析法，确定了抗紫外线老化剂的最佳掺量．结果表明，TiO2和CeO2不仅是好的紫外线吸收或屏蔽剂，而且是一种强氧化剂；炭黑是良好的抗紫外线老化剂，其最佳掺量为沥青质量的0．8％；沥青紫外线老化主要发生在老化前期，老化时间越长老化越严重．

Anti-ultraviolet aging tests of asphalts adapting to environment in Tibetan Plateau of China

Ultraviolet (UV) aging is one of the main factors which cause premature damage of asphalt pavements in the Tibetan Plateau,China.According to the measured levels of UV radiation,aging tests of styrene-butadiene rubber (SBR) asphalts with different contents of three anti-UV-aging agents including nano-TiO2,CeO2 and carbon black are performed.Common indices,which include retained penetration after thin film oven tests (TFOT) and softening point,and strategic highway research program (SHRP) indices of aged asphalts are evaluated.Infrared absorption spectral analysis is performed on asphalt specimens with 0.8% carbon black which have been aged for different aging times (500,1000 and 1 500 h).By grey incidence analysis,the optimal contents of anti-UV-aging agents are determined.The results show that TiO2 and CeO2 are not only good UV absorbing or shielding agents,but also strong oxidants.Carbon black is a good anti-UV-aging agent,and its optimal content is about 0.8% of asphalt weight.UV aging of asphalt mainly occurs in the early stages of aging.The longer the aging time,the more severe the aging of asphalt.