Testing of reclaimed asphalt model systems for the evaluation of the effectiveness of rejuvenators

This paper presents the results of a preliminary study on the use of a novel ap-proach for the evaluation of the effectiveness of rejuvenating agents used in as-phalt mixtures containing reclaimed asphalt (RA). Such an approach is based on the mechanical testing of model systems constituted by a single-sized RA materi-al, in its original state and after pretreatment with rejuvenators, compacted to a target volumetric condition. Model systems were prepared by making use of two rejuvenators and by also considering a reference combination of virgin binder and aggregates extracted from the RA. Tests were carried out for the evaluation of stiffness modulus and indirect tensile strength as a function of curing time. Ex-perimental results showed that the proposed approach can capture the changes occurring in the aged RA binder as a consequence of the effects induced by reju-venators. Quantification of the rejuvenating effects was carried out by analyzing recorded stiffness and strength variations, and by referring to a ductility tough-ness index, introduced to better describe stress-strain response after failure.