Effect of filler in asphalt mastic on rheological behaviour and susceptibility to rutting

ABSTRACT

Mastic, a compound consisting of an asphalt binder and a mineral filler, is an important ingredient in asphalt mixtures, as it is responsible for critical adhesion and viscoelasticity. The rheological properties of mastic are strongly correlated with the rutting potential of asphalt pavement. To explore the impact of filler on the rheological response, three types of asphalt binders and eight types of filler contents were used to fabricate the mastic samples. A modified version of multiple stress creep recovery (MSCR) test selected in this study was regarded as a superior protocol by which to test the rutting potential of asphalt binder and mastic. Based on the rheological behaviour, the 1.0 mm parallel plate gap height was recommended for use in the dynamic shear rheometer (DSR) to evaluate mastic in the MSCR test. The test yielded excellent results with regard to modifier contents, filler contents and stress levels. The regression analysis proved that percent recovery (%R) was a better index for estimating the rheological ability of mastic. Based on the results for %R, the linear viscoelastic region of modified mastic could be expanded by increasing the filler content, while neat mastic demonstrated poor recovery under high stress regardless of filler content. Based on the rheological response, the recommended filler contents were 100%, 120% and 50% for the mastics with 4.0% SBS-modified binder, 3.5% SBS-modified binder and neat binder, respectively.

KEYWORDS:

• Asphalt mastic
• MSCR test
• rheological property
• percent recovery
• filler content

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Disclosure statement

No potential conflict of interest was reported by the authors.