Microstructure of neat and SBS modified asphalt binder by small-angle neutron scattering

FUEL

卷:253

Article

Shan, Liyan¹  Xie, Ru²  Wagner, Norman J.³  He, Hongsen¹  Liu, Yun^3,4 

[1] Harbin Inst Technol, Sch Transportat Sci & Engn, Harbin 150090, Heilongjiang, Peoples R China

[2] ExxonMobil Chem Co, Baytown, TX 77521 USA

[3] Univ Delaware, Dept Chem & Biomol Engn, Ctr Neutron Sci, Newark, DE 19716 USA

[4] NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA

关键词: Asphalt binder;    SANS;    Microstructure;    SBS modified mechanism;   

DOI  :  10.1016/j.fuel.2019.05.087

来源: Elsevier

【 摘 要 】

The microstructure of asphalt binders is believed to have a significant impact on the performance of binders used in roadway constructions. However, there are only limited studies of their nanoscale to microscale structures. Here, small angle neutron scattering (SANS) is used to study the nanoscale structure of neat asphalt binder, styrene-butadienestyrene (SBS) block copolymers and SBS modified asphalt binder. The SANS pattern for asphalt binder demonstrates that it exhibits a colloidal structure comprised of asphaltenes surrounded by resins dispersed in saturates and aromatics. Fractal-core-shell model fits to these patterns indicate that the asphaltene core size decreases with increasing temperature. Both SANS and rheology confirm that SBS modified asphalt has a thermo-reversible phase transition around 110 degrees C, where the SBS micelles swell and lose scattering contrast above this temperature. The thermo-reversibility of this phenomenon indicates that the mechanism of SBS modification is mostly a physical modification of the nanoscale structure as proposed in the colloidal model of asphalt. Modeling of the SANS patterns shows that neat SBS and SBS dispersed in asphalt binder have a lamellar structure surrounded by a shell. These results are useful for understanding the relationship between the nanoscale structure of asphalt binder and pavement performance, as well as potentially developing new types of modified asphalt binders.

【 授权许可】

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