Rutting behavior and Theological modeling of EVA-modified binders in the mixture and binder scales

摘要

This study addressed the rutting potential of binders prepared with ethylene vinyl acetate copolymer (AC+EVA) and this same copolymer combined with polyphosphoric acid (AC+EVA+PPA). Multiple stress creep and recovery (MSCR) tests at 64, 70 and 76 degrees C were conducted in the binder samples, as well as flow number tests at 60 degrees C in the mixture samples. The AC+EVA and the AC+EVA+PPA are equally graded on Superpave (76-xx), and rheological models were selected to further investigate this rutting behavior of the materials. The rankings of the most rut resistant mixturesAC+EVA+PPA, followed by the AC+EVA and the 50/70 base binderare exactly the same according to the binder parameters J(nr) (nonrecoverable compliance from MSCR), G(V) (viscous component of the creep stiffness from the Burgers model) and from the modified power model. However, the parameter J(nr, diff) (percent difference in compliances) showed a diametrically opposite trend in terms of the rutting resistance of binders, and this further suggests its inability to be used as a performance-related parameter in the Superpave specification.