SBS改性高黏沥青机理的多尺度表征

Multi-scale characterization on mechanism of SBS modified high viscosity asphalt

结合宏微观试验与分子模拟,对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改性高黏沥青的改性机理进行多尺度表征.对比高黏剂质量分数为5%~15.5%的高黏沥青流变性能与存储稳定性的变化趋势,基于红外光谱、凝胶色谱与扫描电镜试验,分析高黏沥青微观形貌、官能团、分子量组成的变化特征.开展分子动力学模拟,分析高黏剂与沥青组分相容性、高黏沥青体系稳定性及高黏剂在沥青中的扩散.结果表明:12%高黏沥青兼具较好的流变性能与存储稳定性;高黏沥青制备中基本无化学反应,5%高黏沥青中交联结构初步形成;轻质油提升SBS与沥青相容性,促进SBS分子在沥青中扩散与均匀分布,增强高黏沥青体系稳定性;高黏剂与芳香分的相容性最好,范德华力在高黏剂与沥青的分子相互作用中起主导作用.

The macro and micro tests and the molecular simulation were combined to realize the multiscale modification mechanism characterization of the styrene-butadiene-styrene block copolymer(SBS)modified high viscosity asphalt(HVA).The change trends of the rheological properties and storage stability of HVA with different high viscosity modifier(HVM)mass fractions of 5%to 15.5%were compared.Based on infrared spectroscopy,gel chromatography and scanning electron microscopy,the change characteristics of micro morphology,functional groups and molecular weight composition of HVA were analyzed.Molecular dynamics simulation was carried out to analyze the compatibility between HVM and asphalt components,the stability of HVA system and the diffusion of HVM in asphalt.The results show that 12%HVA has good rheological properties and storage stability.There are basically no chemical reactions in the preparation of HVA,and the cross-linking structure is preliminarily formed in 5%HVA.Light oil enhances the compatibility between SBS and asphalt,promotes the diffusion and uniform distribution of SBS molecules in asphalt,and enhances the stability of HVA system.The compatibility between HVM and aromatic component is the best,and Van der Waals force plays a leading role in the molecular interaction between HVM and asphalt.