Modification effects of multi-walled carbon nanotubes on the mechanical and rheological properties of epoxy asphalt

Epoxy asphalt (EA) was widely used in road engineering fields, but previous research found that there were compatibility problems between epoxy (EP) and asphalt. In practical engineering applications, the compatibility of EA was improved by adding complex auxiliary agents. Although the composite of multi-walled carbon nanotubes (MWCNTs) and epoxy could improve the adhesion, corrosion resistance, and toughness of asphalt, it was difficult to achieve an excellent modification effect because of the agglomeration of MWCNTs. To improve the composite effect of epoxy and MWCNTs, carboxyl functional groups were added to MWCNTs under mixed acid conditions to reduce the agglomeration and achieve a better combination with epoxy. Then, MWCNTs/EP was prepared under physical stirring conditions. The MWCNTs/EP was observed by scanning electron microscopy (SEM), and it was found that MWCNTs could be uniformly dispersed in epoxy. To research the modification effect of MWCNTs on mechanical and rheological properties of EA, a variety of MWCNTs/EA with different proportions were prepared. The impact of different mixing ratios of MWCNTs/EP on the mechanical and rheological properties of asphalt was evaluated by dynamic shear rheological (DSR) experiments. The results showed that the addition of the appropriate amount of MWCNTs could further improve the high-temperature stability of EA. In this case, MWCNTs played a positive role in the modification of epoxy. However, the improper introduction of MWCNTs would have a negative weakening effect, which would weaken the hightemperature performance of EA. Through comparison, the optimal mixing ratios of MWCNTs and epoxy were finally determined as 6 % EP + 1.4 % MWCNTs and 20 % EP + 0.125 % MWCNTs.