Mechanism, rheology and self-healing properties of carbon nanotube modified asphalt

Multi-walled carbon nanotubes (MCNT) are widely employed to modify the bitumen due to their excellent properties. However, there is limited research on using MCNT to accelerate the self-healing properties of bitumen. In this study, MCNT was adopted to achieve this aim. The compatibility and modification mechanism were observed by a Fluorescence Microscope (FM) and Fourier Transform Infrared Spectroscopy (FTIR). Then, the rheological properties were investigated using a DSR and BBR machine. Finally, the initial healing temperature and self-healing properties were evaluated. Results indicated it will occur agglomeration when the content of MCNT exceeds 1.5%, and the modification mechanism between MCNT and bitumen is physical blending. The high-temperature and low-temperature rheological performance will be improved and decreased with MCNT respectively, which is consistent with the results of master curves. Furthermore, the incorporation of MCNT will reduce the flow behavior index and thus increase the initial healing temperature. There is no difference in healing effect at room temperature; however, modified asphalt with 1.5% content MCNT exhibited the best healing efficiency when they are healed at their respective healing temperatures.
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