Identification of Microstructures Affecting High-Temperature Performance of Various Oil-Sourced Asphalt Binders

The high-temperature performance of asphalt binders is not only influenced by the characteristics of raw materials, but also closely related to their microstructures. Effects of aging on rheological performance, physical performance, and chemical performance of asphalt binders were analyzed. The key microstructural parameters governing the high-temperature performance were investigated using gray relational analysis. The results showed that high-temperature performance of HB 70# and SX 90# asphalt binders were superior to asphalt binders from other oil sources. Styrene-butadiene-styrene (SBS)–modified asphalt binder had significant elastic recovery ability and excellent high-temperature stability. Only the carbonyl index of aged asphalt binders showed a continuous increase. Carbonyl index was the most sensitive index with a maximum change of more than 300%. Asphalt binders contained the highest content of H β , ranging from 54.96% to 75.23%, and the lowest content of H A , ranging from 1.30% to 6.77%. Aging resulted in a reduction of hydrogen atoms on aromatic rings and an increase in straight-chain segments in asphalt binders. A strong correlation (0.93) was found between the carbonyl index and the irrecoverable creep flexibility ( J n r ) at a stress level of 0.1 kPa. The differences in high-temperature performance between asphalt binders from different oil sources were mainly determined by carbonyl functional group.