The influence of long-term aging on the chemical properties of bitumen

Abstract

To further explore the long-term aging influence on the chemical properties of bitumen, laboratory aging methods were employed to obtain the aged binders with different long-term aging degrees. The chemical properties of virgin and various aged bitumen were evaluated through TCL-FID, ATR-FTIR, Elementary analysis and GPC tests. The chemical characterization results showed that as the aging degree deepened, the resin and asphaltene fractions with larger molecular weight increased dramatically, which resulted in the rise of average molecular weight and the more unevenly molecular weight distribution in aged bitumen. Moreover, the aging of bitumen would lead to the increase of the oxidized functional groups (C=O and S=O) index, oxygen content, aromaticity and polarity, while the reduction of carbon, hydrogen element contents and the H/C ratio.