Effect Of Inorganic Fillers On The Structure And Rheological Properties Of SBS Modified Bitumen

In the thesis,the microstructure induced by phase separation and corresponding rheological behavior of bitumen modified by SBShas been studied in presence of inorganic fillers.Due to the immiscibility between SBS and bitumen,two-phase structure can be induced by phase separation in their blends.It is found that the addition of SiO₂nanoparticles would influence the microstructure and rheological behavior of bitumen/SBS modified blends,which is dependent on its surface nature,fraction and the dispersion of nanoparticles.Rheological results indicate that thehydrophobic SiO₂ modified bitumen/SBS blendshave much better rheological property of the rutting resistance revealed by complex modulus and phase angle than the hydrophilic SiO₂ modified blends.The surface structure of blends measured by SEM,indicates that,thehydrophobic SiO₂would reduce the size of bee structure of blends system,due to the preferential attraction between bitumen andhydrophobic SiO₂.The rheological property exhibits a nonmonotonic change with SiO₂ fraction either inhydrophobic SiO₂ orhydrophilic SiO₂ modified blends.When the addition of SiO₂ exceeds a critical value,rutting resistance of system would decrease because of the coupling effects of SiO₂ nanoparticles distribution and their aggregates.Optical microscopy results suggest that the bitumen/SBS blendshave the droplet-matrix structure with different droplet size,the addition of SiO₂ nanoparticles does not change the type of phase separation structure.DSC results reveal that the addition of SiO₂ nanoparticles can enhance the temperature sensitivity of bitumen/SBS blends.It is found that the addition of micro glass bead?GB?would influence the rheological behavior,phase structure and bee structure of bitumen/SBS blends.This effect is related to the dependent on the size,fraction and disperison of micro glass bead.It is found that either the GB fraction or size can influence the rheological property of bitumen/SBS/GB blends.All the modified bitumen systems keep a droplet-matrix type,and the addition of micro glass bead does not change the type of phase separation structure but influence the size of SBS-rich phase.The difference in the interfacial area fraction,obtained by Image J analysis reflects the effect of GB size on the rheological property.The smaller the interfacial area fraction of SBS-rich phase is,the better compatibility the blend has.The bee-like structure?Catana phase?observed by AFM respectively is also investigated,it is found that the ratio of specific amplitude to the wavelength?A₀/?₀?of bee-like structure can effectively measure the ieffect of particle size of micro glass bead on rheological properties of blends.A lower value of A₀/?₀ indicates the modified bitumen with higher stiffness.When the chemical composition is the same,the lower value of A₀/?₀ indicates the modified bitumen with higher stiffness.