Rheological and aging properties of warm mix asphalt binders containing expanded vermiculite

The scope of this study was to investigate the high and intermediate temperature rheological and aging properties of warm mix asphalt binders modified by organo-expanded vermiculites. The rotational viscosity, complex modulus, and rutting parameter (G*/delta) increased and the penetration and phase angle decreased after modification of 3% organo-expanded vermiculites, indicating that the high temperature rheological properties of the warm mix asphalt binder have been improved. The warm mix asphalt binders containing 3% organo-expanded vermiculites demonstrate the lowest value of phase angle and the highest value of complex modulus compared with the studied binders. In addition, as a result of the rolling thin film oven test, the viscosity aging index of warm mix asphalt binder decreases, while the retained penetration increases obviously with the introduction of organo-expanded vermiculites. The warm mix asphalt binder with 3% organo-expanded vermiculites has more pronounced improvements in aging resistance in comparison with other studied modified warm mix asphalt binders.