Characteristics and Mechanism of SBS Modified Asphalt’s Phased Aging

Abstract:

Microscopic tests, e.g. fluorescence microscopy, infrared spectroscopy and gel chromatography were used to analyze the changes of micro phase structure, oxygen inhalation level of asphalt phase and molecular size makeup during aging phase of styrenebutadienestyrene block copolymers(SBS) modified asphalt. Test and analysis results show that the aging of the SBS modified asphalt has two distinct aging phases. In the first aging phase, the oxygen inhalation rate of asphalt was low; the proportion of small molecules almost remains the same; the SBS particles gradually decrease in size and eventually agglomerate and segregate. In this phase, the toughness of the SBS modified asphalt gradually reduces until complete loss. In the second aging phase, the oxygen inhalation rate of asphalt significantly increases and the proportion of small molecules reduces. In this phase, as styrene still plays the role of modification after SBS’s degradation, asphalt’s consistency increases while its softening point tends to rise.