Laboratory testing on the anti-aging performance of amorphous poly alpha olefin (APAO) modified asphalt binders

Abstract

The objective of this study is to examine the aging characteristics of amorphous poly alpha olefin (APAO) modified asphalt binders. The anti-aging performance of APAO modified asphalt binders were investigated through a comprehensive laboratory program. The content of APAO was 2%, 4%, 6% and 8% of the mass of the asphalt binders. The asphalt binders underwent the rolling thin film oven (RTFO) test and pressure aging vessel (PAV) test. The aging characteristics of asphalt binders were evaluated with rotational viscometer (RV), dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The morphological properties of asphalt binders were investigated with the Fourier transform infrared spectrum (FTIR) tests. The conventional performance of asphalt binder was improved after mixed with APAO. The optimum APAO content was 6% by mass of asphalt binders for proposed 70# asphalt according to comprehensive test of APAO modified asphalt binders (AMB). The high temperature performance grade of AMB was increased without sacrificing the low temperature performance grade, and the temperature susceptibility was increased under different aging conditions. The aging performance of AMB was verified to be better than base asphalt binders. The rutting resistance of AMB was improved significantly even after short- and long-term aging. The base asphalt binders and APAO went through physical mixing and chemical reaction in the process of mixing. The carbonyl and sulphoxide index verified the higher anti-aging performance of AMB on a morphological scale.