Investigating effects of ethylene vinyl acetate and gilsonite modifiers upon performance of base bitumen using Superpave tests methodology

In this research study, relative performance of a series of ethylene vinyl acetate (EVA) and gilsonite modified bitumens were evaluated in terms of three main distress modes of flexible pavement namely rutting, fatigue damage and low temperature cracking. Seven modified and unmodified bitumens were tested and characterized in accordance with the Superpave performance criteria. The experimental tests performed were dynamic shear rheometer (DSR), bending beam rheometer (BBR) and rotational viscosity (RV). DSR test results for rutting showed that addition of EVA and gilsonite increase the rutting parameter (G∗/Sin(δ)) of the modified bitumens relative to the base bitumen. DSR fatigue test results showed that addition of EVA decreases the fatigue parameter (G∗Sin(δ)) of modified bitumens while addition of gilsonite increases the fatigue parameter of modified bitumens. BBR test results showed that addition of EVA decreases the creep stiffness (S-value) of modified bitumens while addition of gilsonite increases the creep stiffness of modified bitumens. Moreover, the addition of 2% and 4% EVA increase the m-value of modified bitumens while addition of gilsonite decreases the m-value of modified bitumens.