Use of recycled oils as rejuvenators for bituminous binders

The addition of rejuvenators agents (RJ) into bitumen allows increasing the amount of recycled asphalt in new mixtures. In the preliminary part of this study, three different type of oils were tested as potentials RJ: a mineral oil from the automotive industry, a waste domestic cooking vegetable oil (VO), and a biodiesel. Several mixtures were prepared by adding different percentage of oils and VO was individuated as the best RJ. Therefore, VO was used in a further investigation, to better characterize the properties of the rejuvenated binder and its resistance to aging during a second life cycle. Rejuvenated binders with different oil content were prepared and evaluated. The rheological characterization included frequency sweep tests to obtain the binder master curves and linear amplitude sweep test to evaluate the cumulative damage resistance. Moreover, the molecular weight distributions of the binders were investigated by both gel permeation chromatography and rheology by application of the delta-method.