Property transitions of neat and styrene–butadiene-styrene (SBS)-modified asphalt binders from small, medium to large-amplitude oscillatory shears

ABSTRACT

Tests on asphalt binder are typically performed in its linear viscoelastic (LVE) range. In this research, the rheological properties of neat and styrene–butadiene-styrene (SBS)-modified asphalt binders were examined from 0.01% to 1000% at a high usage temperature, and focus was placed on their non-linear viscoelastic (NLVE) behaviours. Experimental variations and binder property changes in small, medium and large-amplitude oscillatory shears were revealed. Besides strain amplitude, the effects of polymer content, short-term aging and test frequency on NLVE behaviours were also analysed based on three quantitative methods. Additionally, polymers in asphalt binders were examined by using confocal fluorescence microscopy. The NLVE behaviours were found to be affected by shear strain amplitude, polymer content, shear frequency, and the interactions of such factors, but to a less extent by short-term aging. Besides polymer content, the size and morphology of polymer phase likely affect the property variations of modified asphalt binders. Large amplitude oscillatory shear (LAOS) test and morphology analysis help identify the threshold polymer content in producing high-quality polymer-modified asphalt binders.

KEYWORDS:

• non-linear viscoelastic (NLVE) behaviours
• large amplitude oscillatory shear (LAOS)
• SBS-modified asphalt binder
• confocal fluorescence microscopy
• Fourier transform (FT) rheology
• stress decomposition

Disclosure statement

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

Additional information

Funding

This paper is based on the research projects (Project No. 15204819, 15213020) funded by the Research Grants Council of Hong Kong Special Administrative Region Government.