The laboratory performance of asphalt mixture with Amorphous poly alpha olefins (APAO) modified asphalt binder

In this paper, asphalt binder was blended with 0%, 4%, 6%, and 8% Amorphous poly alpha olefins (APAO) to prepare modified asphalt binders. Based on the penetration, ductility, softening point, and Dynamic Shear Rheometer (DSR) test, 6% APAO was the optimal dosage in asphalt binder performance perspective. The dense graded aggregate was mixed with APAO modified asphalt binder to prepare the APAO modified asphalt mixture. The volumetric parameters of the asphalt mixture with APAO modified asphalt binder was tested. The standard Marshall stability test, immersion Marshall test, Freeze-thaw splitting test, and Marshall stability of aged asphalt mixtures test were conducted on asphalt mixtures with APAO modified asphalt binder. Based on the Marshall stability test, immersion Marshall test, and Freeze-thaw splitting test, asphalt mixture with 6% APAO possessed the best high temperature performance, the highest moisture damage resistance, and the least splitting tensile strength loss after the freeze-thaw conditions. The tensile strength decreased after the addition of APAO. There was only negligible tensile strength difference between asphalt mixture with 4% APAO and 6% APAO. Based on the Marshall stability and retained Marshall stability ratio (RMSR) of asphalt mixtures after aging, the optimal content of APAO was 6%. Therefore, 6% APAO was the optimal content for both modified asphalt binder and APAO modified asphalt mixture.