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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—CC—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 relationship between macroscopic performance and microscopic molecular structure under the condition of coupling aging, macroscopic properties of matrix asphalt and SBS modified asphalt under different aging conditions were tested respectively by penetration, ductility, softening point and viscosity test. The microscopic molecular structure of bitumen was tested by FTIR and H-NMR spectra. The gray system theory was used to calculate the relationship between macroscopic conventional properties and microscopic molecular structure under the conditions of coupled aging. The proposed model formula. The results show that the macroscopically regular properties of asphalt gradually deteriorate with the aging degree and aging time, the carbonyl index (CI) and sulfoxide index (SI) increase gradually, the chemical bond fracture and oxidation addition reaction of asphalt occur, butadiene index BI gradually decreased, SBS modifier - CC-double bond degradation reaction; linear SBS modified asphalt aromatic ring isomerization dealkylation, the base asphalt and star SBS modified asphalt aromatic ring first dehydrogenation condensation , Followed by isomerization and dealkylation. Both the matrix asphalt and the SBS modified asphalt aliphatic region were structurally alienated, the length of the side chain of the pitch was gradually reduced, the side chain length of the star shaped SBS modified asphalt was gradually increased, and the linear SBS modified The length of the side chain of the asphalt first decreases and then increases. According to the calculation results of the macroscopic and microscopic molecular structural features of asphalt and the gray relational degree between the two, the SBS modifier can significantly improve the anti-aging performance of the asphalt, and different types The effect of SBS modifier on the anti-aging performance of the common matrix asphalt is quite similar. The microscopic molecular structure change of the asphalt under the coupled aging conditions is most significantly related to the matrix asphalt softening point. Transition point, penetration and associated 5 ℃ most significant ductility. Through the macroscopic general performance index of bitumen, it can predict the variation law of microscopic molecular structure of asphalt.