Laboratory evaluation of ethylene vinyl acetate modified bitumens and mixtures based upon performance related parameters

In this research study, relative performance of a series of ethylene vinyl acetate (EVA) modified bitumens and mixtures were evaluated in terms of three main distress modes of flexible pavement namely rutting, fatigue damage and low temperature cracking. Four modified and original base 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). DSR test results for rutting showed that addition of EVA increase the rutting parameter (G∗/Sin(δ)) of the modified bitumens relative to the original base bitumen. DSR fatigue test results showed that addition of EVA decreases the fatigue parameter (G∗Sin(δ)) of modified bitumens. BBR test results showed that addition of EVA decreases the creep stiffness (S-value) of modified bitumens relative to the original base bitumen. Moreover, the addition of 2% and 4% EVA increase the m-value of modified bitumens relative to the original base bitumen. The effects of the ethylene-vinyl-acetate (EVA) on asphalt mixture performance were also investigated. Dynamic creep test, indirect tensile fatigue test, indirect tensile strength test and creep compliance test were performed on modified asphalt mixtures by 2%, 4% and 6% EVA and the asphalt mixture containing original base bitumen. Results of dynamic creep test and indirect tensile fatigue test conducted on the EVA-modified asphalt mixtures showed that addition on EVA improves rutting and fatigue resistance of asphalt mixtures relative to the asphalt mixture containing original base bitumen. Low temperature cracking resistance of EVA-modified mixtures at 2%, 4% improved compared to the asphalt mixture containing original base bitumen.