耦合老化条件下沥青性能与分子结构特征分析
Feature analysis on performance and molecular structure of asphalt under coupling aging conditions

为了构建耦合老化条件下沥青宏观性能与微观分子结构特征的相关关系，分别通过针入度、延度、软化点和黏度试验，测试不同老化条件下基质沥青和SBS改性沥青宏观常规性能，通过FTIR（红外光谱）和H-NMR（核磁共振氢谱）试验测试沥青的微观分子结构；采用灰色系统理论计算耦合老化条件下沥青宏观常规性能与微观分子结构的关联程度，并给出其拟定模型公式。研究结果表明：随着老化程度及老化时间的增加，沥青各项宏观常规性能逐渐劣化，羰基指数CI和亚砜基指数SI逐渐增大，沥青发生化学键断裂和氧化加成反应，丁二烯指数BI逐渐减小，SBS改性剂发生―C=C―双键降解反应；线形SBS改性沥青芳香环发生异构化脱烷，基质沥青与星形SBS改性沥青芳香环先发生脱氢缩合，然后发生异构化脱烷；基质沥青和SBS改性沥青脂肪族区均发生结构异化，基质沥青脂肪侧链长度不断减小，星形SBS改性沥青侧链长度逐渐增加，线形SBS改性沥青侧链长度先减小后增加；从沥青各项宏观性能和微观分子结构特征的变化趋势以及两者灰色关联度的计算结果看，SBS改性剂能够显著提高沥青抗老化性能，且不同类型SBS改性剂对常用基质沥青抗老化性能的改善效果相当；耦合老化条件下沥青的微观分子结构变化与基质沥青软化点的关联最显著，与SBS改性沥青软化点、针入度和5 ℃延度的关联最显著。通过沥青宏观常规性能指标可以预测沥青微观分子结构的变化规律。
In order to establish the correlation between the conventional macro-performance and the micro-molecular structure of asphalt under coupling aging conditions, the conventional macro-performances of matrix asphalt and SBS modified asphalt under different aging conditions were tested respectively by penetration, ductility, softening point and viscosity test, and the micro-molecular structure of asphalt under different aging conditions were tested by Fourier transform infrared spectroscopy (FTIR) and H-nuclear magnetic resonance spectroscopy(H-NMR). Finally, the grey system theory method was used to calculate the degree of association between conventional macro-performances and micro-molecular structure of asphalt under coupling aging conditions, and model formula was given. The results show that with the increase of aging degree and aging time, each conventional macro-performance of asphalt gradually deteriorates. Carbonyl index and sulfoxide index gradually increases, and chemical bonds breaking and oxidation addition reaction occur in the asphalt. Butadiene index gradually decreases, and ―C=C― of SBS modifier gradually degrades. Additionally, aromatic rings of linear SBS modified asphalt undergo isomerization dealkylation, matrix asphalt and star-type SBS modified asphalt occur dehydrogenation and condensation reaction first and then isomerization dealkylation. Structure alienation happens to the aliphatic region of matrix asphalt and SBS modified asphalt. Length of aliphatic side of matrix asphalt gradually decreases, and star-type SBS modified asphalt increases, while linear-type SBS modified asphalt decreases first and then increases. Based on the analysis results of conventional macro-performances, micro-molecular structure and grey correlation degree between them, SBS modifier could significantly improve the aging resistance of asphalt and different types of SBS modifier are pretty on the effect of improving aging resistance of asphalt. Under coupling aging