Rheology, morphology and phase behavior of SBS/sulfur modified asphalt based on experimental assessment and molecular dynamics

ABSTRACT

Past studies broadly discussed the effect of sulfur on the rheological properties of styrene–butadiene–styrene (SBS) modified asphalt, while the relationships between the rheological properties and phase behaviour of SBS-modified asphalt after sulfur vulcanisation have received less attention, which limits the further understanding of the relations between the structure and performance. To this end, this paper is aimed to discuss viscoelastic response at the molecular level and reveal the enhancement mechanism of SBS-modified asphalt after adding sulfur. Thus, the morphology, phase structure, and rheological behaviour of SBS/Sulfur modified asphalt were investigated by experimental assessment and molecular dynamics. Based on the results, it was found that the polybutadiene segments in SBS copolymer are the leading reactive site of vulcanisation, the interactions between SBS copolymer and light components were enhanced by sulfur treatment, the orderliness of asphalt molecules in SBS/sulfur modified asphalt was strengthened, and SBS copolymer presents a stronger attraction to aromatic after vulcanisation, which means the increase of boundary layer is also the significant cause to the improvement of compatibility. The findings are expected to deepen understanding of the vulcanisation mechanism and the rheological behaviour of SBS/Sulfur modified asphalt.

KEYWORDS:

• Rheology and morphology
• SBS modified asphalt
• vulcanisation
• phase behaviour
• molecular simulation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was mainly supported by National Key R&D Plan (Grant numbers: 2016YFE0202400). The support from the National Natural Science Foundation of China [Grant No. U1633201] is also appreciated.