Rheological properties, microstructure and aging resistance of asphalt modified with CNTs/PE composites

Nanomaterials for asphalt modification and incorporating nanoparticles into asphalt mixtures to deal with road failure have gained popularity recently. Researchers have reported the improved performance of asphalt modified by carbon nanotubes (CNTs), but the cost is very high with the relatively high CNTs content. This work studied the composites modification for asphalt by CNTs and polymer with a relatively low dosage. Combined adding CNTs and polyethylene (PE), and pre-melting-mixed CNTs/PE composites were selected for preparation of modified asphalt in the study. The rheological properties as well as anti-aging performance were investigated using dynamic oscillation shearing, steady state shearing, MSCR, Fourier transform infrared (FT-IR) spectroscopy and Scanning Electron Microscopy (SEM). The influence of CNTs/PE composites on viscoelasticity as well as anti-aging performance was illustrated. The results indicated that CNTs and PE have synergistic effect on improving the high temperature performance of asphalt binders (verified by increased modulus, higher viscosity, etc.), indicating improvement on rutting resistance. Premixed CNTs/PE composites benefits for the low temperature cracking resistance and has the good anti-aging performance. No new absorption peaks appeared in FT-IR spectrum of CNTs/PE modified asphalt after aging, whereas a number of micro-cracks occurred in the SEM of aged asphalt with CNTs & PE. Microstructure evaluation indicated that premixed CNTs/PE composites can delay the aging degree of asphalt. (C) 2020 Elsevier Ltd. All rights reserved.