Viscoelastic and Morphological Evaluation of Aged Polymer Modified Asphalt Binders

Abstract

Asphalt binder is a complex viscoelastic material. It implies that based on temperature and loading, its behaviour changes from a viscous material to an elastic material. Modification and ageing further add to this complexity. Over the years, a number of studies have examined all the aspects of polymer-modified binders (PMB), but there is still work needed to correlate the viscoelastic behaviour of the PMBs to their morphological behaviour. So, in the present study PMBs are prepared by modifying VG-10 base binder with the help of styrene butadiene styrene and ethylene vinyl acetate. Binders were aged using rolling thin-film oven test and pressure ageing vessel. Viscoelastic and morphological evaluation of binders was carried out by using dynamic shear rheometer and scanning electron microscopy (SEM), respectively. The test results showed that polymer modification enhances the thermorheological complexity of the base binders, while ageing does not affect it. Linear viscoelastic limits of the binders were found to be decreasing after ageing and modification. Ageing degrades the polymer network so after ageing PMBs were found to be behaving similar to base binder. The SEM results support these results.