Characterization of the rutting potential of modified asphalt binders and its correlation with the mixture's rut resistance

This study was intended to evaluate the susceptibility of asphalt binders and mixtures to rutting. The binders have the same high PG grade (PG 76-xx) and a dense-graded gradation curve was used to produce the mixtures. Three types of polymers - Elvaloy®, SBS and SBR - and polyphosphoric acid (PPA) were selected. The tests included softening point, oscillatory shear (parameter G∗/sinδ), multiple stress creep and recovery (Jnr) and flow number (FN). The rankings of binder and mixture parameters (Jnr, G∗/sinδ, softening point and FN) are the same only for Jnr and FN, and the applicability of G∗/sinδ to modified materials is questionable.