Multi-Modified Effects on the Nano-Sized Topography and Pull-Off Strength of High-Viscosity Asphalt Binders Based on Varied Modifiers

The application of high-viscosity asphalt binders can significantly improve the performance of asphalt pavement, but with the increase of viscosity at high temperature, the carbon emissions during the construction of asphalt pavement increases significantly. The dynamic viscosity of high-viscosity asphalt binders depending on the content of TPS modifier was found to be related to interfacial bond strength between the asphalt binders and aggregates, but not clearly. To strengthen the interfacial bonding strength of high-viscosity asphalt binders by using less content of domestic TPS-modifier and SBS as well as to reduce carbon emissions of the construction of asphalt pavement, the hybrid modified method and some types of asphalt binders was selected in this research. They are a base asphalt binder, an SBS- modified asphalt binder producing in factory with the SBS content is 4.5 wt.%, some TPS-SBS-modified asphalt binders producing in laboratory with the TPS content is 13.6 wt.% plus SBS contents are 0, 3.0, 4.5, 6.0 wt.%. This research firstly studied the nano-sized microstructure topography of these types of asphalt binders. Then, the macro pull-off strength and rotational viscosity of these asphalt binders were both tested. Finally, the relationship between nano-sized and macro properties was detailed explored. Results indicated that (1) the added TPS modifiers remarkably altered the nano-sized topography of the base asphalt binders as well as the typical "bee like structure", while the SBS modifiers altered less; (2) the TPS modifier markedly condensed the nano-sized of the "bee like structure" at 3D scale, while the plus SBS modifier establishing the network structure to some extent bordered the "bee like structure"; (3) the pull-off process of the base asphalt binder was more like brittle fracture, but the strength was bigger than the other modified asphalt binders, especially much bigger than the hybrid modified formulas; (4) the pull-off strength of asphalt binder increased as the AFM indexes of ISAD and Rmax increased, while the other two indexes de-creased; ( 5) the domestic TPS-modifier content of 13.6 wt.% plus SBS 3.0 wt.% is recommended by the rotational viscosity at high temperature and pull-off strength.