紫外老化对沥青力学行为及聚集态的影响

Influence of Ultraviolet Aging on Mechanical Behavior and Aggregated State of Asphalt

为了研究紫外环境下老化对沥青聚集态的影响,分析材料性质变化的化学机理,以动态流变学的手段对比了老化前后沥青的力学行为,运用时温等效原理的失效温度分析沥青聚集态的变化,利用红外光谱、紫外光谱考察了紫外老化过程中沥青组分的迁移和胶体结构变化。结果表明:紫外老化后沥青流变特性变差,常温下材料性能由柔而软变为刚而硬;沥青出现相态分离现象是流变特性变差、力学行为改变的内在原因;紫外老化改变了沥青组分的平衡和稳定,老化过程中,胶质沥青质发生缔合,产生超分子结构,逐渐聚集、沉淀;随着紫外老化时间的延长,沥青原来的胶体结构被破坏,逐渐由溶胶向凝胶、由胶体向固体转变。

In order to study the influences of ultraviolet aging on asphalt aggregated state,the chemical mechanism of material physics property change was analyzed,mechanical behaviors of asphalt before and after aging by using dynamic rheological methods were compared.Based on the invalidation temperature of the time-temperature superposition principle（TTSP）,the changing of aggregated state was analyzed,infrared spectrum and ultraviolet spectrum were used to observe transforming of chemical groups of asphalt and variation of colloid configuration during ultraviolet aging.The results show that rheological character after ultraviolet aging degrades,asphalt binder transforms from viscous material to elastic material under normal temperature.The intrinsic reason of rheological performance degradation and mechanical behavior changing is aggregated state separating.Ultraviolet aging breaks balance and stability of chemical groups of asphalt.Supermolecule structure forms through combination of resin and asphaltene conglomerate and aggregates and deposites little by little.Asphalt colloid structure is destroyed,and becomes gelatin from sol with aging time extending.