紫外光吸收剂对SBS改性沥青选择性抗老化作用机理的研究

SBS改性沥青以其优良的高低温性能广泛应用于高等级公路建设中。在沥青路面服役期间，SBS改性沥青直接暴露于阳光照射之下会发生紫外光老化，造成路面裂缝、坑槽等病害。添加紫外光吸收剂是改善SBS改性沥青耐老化性能的有效方法之一。然而，前期研究结果表明紫外光吸收剂对SBS改性沥青的抗老化性能具有特定的选择性，而二者之间的选择性抗老化作用机理目前尚不明确。本项目拟以不同结构的紫外光吸收剂与SBS改性沥青为研究对象，研究紫外光吸收剂对SBS改性沥青物理、流变、热氧及紫外光老化性能的影响，利用现代分析测试手段，探明紫外光吸收剂/SBS改性沥青老化前后组成、结构与微观形貌的变化规律，构建紫外光吸收剂/SBS改性沥青组成、结构与性能一体化关系，建立紫外光吸收剂、SBS共聚物、沥青共混体系动力学模型，揭示紫外光吸收剂对SBS改性沥青选择性抗老化的作用机理，为耐久性道路沥青材料的制备提供理论指导。

Styrene-butadiene-styrene (SBS) modified bitumen is widely used in the high-grade pavement due to its excellent performance at high and low temperatures. However, the SBS modified bitumen exposed to the sunlight directly will suffer from ultraviolet (UV) aging during its service life, causing many diseases of the pavement (e.g. cracking, pit holes, etc.). The addition of UV absorber is an effective way to improve the aging resistance of the SBS modified bitumen. Previous researches by the applicant show that the UV absorber exhibits a specific selectivity on the aging resistance of the SBS modified bitumen. However, the mechanism of this specific selectivity is not clear at present. This project will select different kinds of UV absorber and different types of SBS modified bitumen as the main objects to investigate the influences of these UV absorbers on physical, rheological, thermal-oxidative and UV aging properties of the SBS modified bitumen. The changes in chemical compositions, structures and microtopography of the UV absorber/SBS modified bitumen before and after aging will be explored through various analytical methods. Based on these, the integrated relationship among compositions, structures and properties will be established. The dynamic model of the blending system including the UV absorber, SBS polymer and bitumen will be formed. Finally, the mechanisms of UV absorber on selective resistance to aging of SBS modified bitumen will be revealed, which will provide theoretical guidance for the preparation of endurable bituminous materials.