基于组分挥发与基团变化的沥青老化机制研究

Investigation on Bitumen Ageing Mechanism by Components Volatilization and Functional Group Changes

在道路建设领域,沥青材料越来越受到重视,然而,沥青的老化也随着加热拌和、摊铺、服役一直存在,其结果是使沥青的路用性能发生劣化.通过气相色谱-质谱联用技术模拟并测试了沥青的物理性老化、使用TFOT,PAV,UV,酸溶液浸泡模拟了沥青的化学性老化.并使用四组分测试与红外测试,研究了沥青的老化机制.研究结果表明,短期老化条件下主要发生轻质组分挥发,且挥发物复杂程度受温度影响较大;压力老化对沥青四组分与官能团影响最大,四组分与基团均发生大幅度变化;紫外老化主要影响硫原子所带的化学键,使亚砜基大幅增多;酸性环境下,沥青中的芳香分增多,但胶体结构仍遭到破坏.四种老化模式均会降低沥青的胶体稳定性指数.

Bituminous materials become increasingly important in road construction field. However, ageing, which results in deteriorate in pavement performance, runs through the whole life of bitumen, including heating, mixing, paving and servicing period. In this research, GC-MS is used to simulate and characterize the physical ageing of bitumen by means of volatile components. TFOT, PAV, UV and acid solution are used to accelerate the chemical ageing of bitumen while four components and FTIR spectrogram are used to characterize the mechanism of chemical ageing. The result shows that the light fraction mainly volatize in TFOT process. The higher the temperature is, the more complex the components volatize. PAV exerts the biggest impact on four components and functional group in bitumen. UV ageing leads to more sulfoxide group. The aromatic increases in acid circumstance. The colloid structure is destroyed anyway. All the ageing accelerate methods decrease the index of colloid stability.