Performance degradation of styrene-butadiene-styrene modified asphalt binder at ultra-high temperature: Process of construction in fluid mastic asphalt

Fluid mastic asphalt (FMA) is a skeleton dense hot-mixed asphalt mixture with the internal porosity of less than 1 %, which is formed by mixture fluidity or vibration-assisted slurry extraction. In order to improve the fluidity of SBS modified asphalt binder used in FMA, it should be heated at ultra-high temperature which refers to 200 degrees C and above. The performance degradation of asphalt binder which is heated at ultra-high temperature in the asphalt storage tank cannot be avoided. At present, there are few studies on the performance degradation of SBS modified asphalt binder in the process of construction at ultra-high temperature. This study proposes an aging test method which is aging of large volume (ALV) and then short-term aging in laboratory which aims to replace extraction and recovery from old asphalt mixture. The macro performance of SBS modified asphalt binder are analyzed by penetration, ductility, softening point, dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The microscopic changes of SBS modified asphalt binder are analyzed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The results shows that, taking aging of large volume at 165 degrees C as the standard, the change rate of that before and after short-term aging and mix change between that and other kind of aging of large volume reaches a third and above. The carbonyl group occurs in the infrared spectrum of aging in the form of volume at 225 degrees C but else asphalt binder which undergo aging in the form of volume at other temperature do not. The molecular weight decreases significantly and the distribution range becomes wider.