Rheology and microstructure of asphalt binders

The viscous and linear viscoelastic properties of different asphalt binders have been analyzed in this paper. Thus, an unmodified bitumen, a polymer-m odified (SBS) bitumen, a commercial synthetic binder, and two model synthet ic binders with different polymer (SBS) concentrations have been studied. T he mechanical spectra of these binders are quite different, mainly influenc ed by SBS concentration. Thus, up to three regions may be observed for a sy nthetic binder with high polymer concentration. The temperature dependence of the zero-shear-rate-limiting viscosity is described by an Arrhenius-like equation, in a temperature range that depends on binder composition. These results have been discussed taking into account the development of a polym er-rich phase in SBS-modified bitumen and model synthetic binders.