| Abstrakt: |
This paper discusses the ageing features of SBS modified asphalt and its assessment index. The performances for both host asphalt and modified asphalt after different RTFOT ageing times was tested and micro analysis was conducted with infrared spectrum. The quantitative analysis for the micro-changes of ageing process was carried out according to Lambert Beer law. The research results show that the longer the ageing time, the smaller the penetration and ductility of asphalt are, and the greater the softening point and viscosity. In comparison with the host asphalt, the absorption peak of SBS modified asphalt in stretching vibration (C=C) at 1600cm-1, the absorption peaks of polybutadiene in bending vibration at 966cm-1 and 911cm-1 , and the absorption peak of styrene in bending vibration at 697cm-1 are from SBS modifier. The oxygen reaction happens in ageing process of asphalt, producing carboxyl and subsulfoxide. Affected by the higher activity of SBS modifier, SBS modified asphalt can be easily oxidized.There is good correlation between its penetration, softening point, ductility with carboxyl and subsulfoxide , so the above three indexes can be adopted to assess the ageing of SBS modified asphalt. |
