In view of environmental and economic aspect, asphalt was modified with recycled packaging waste expended polystyrene （WEPS） instead of common polymer. The differential scanning calorimetry （DSC）, rotational viscometer and dynamic shear rheology （DSR） were used to analyze and evaluate the viscoelasticity of modified asphalt. Results indicate that the sensitivity of modified asphalt to temperature is decreased while the rut resistance of asphalt is increased. In addition, the viscoelasticity of asphalt is improved after the modification with WEPS. Besides, the modified asphalt has high viscosity at low temperature and low viscosity at high temperature, which is favorable for construction.
Waste polyethylene packaging （WPE） was used to modify asphalt, and hot storage stability of the modified asphalt was studied in this paper. The morphological change and component loss of WPE modified asphalt were characterized by fluorescence microscopy, Fourier transform infrared spectroscopy （FT-IR）, differential scanning calorimetry （DSC）, thermogravimetry （TG） and isolation testing. In addition, the mechanism of the hot storage stability of WPE modified asphalt was discussed. The results showed that the modification of asphalt with WPE was a physical process. It was found that the filament or partly network-like structure formed in the modified asphalt system was beneficial to improving the hot storage stability. Moreover, the addition of WPE resulted in a decrease in both the light components volatilization and the macromolecules decomposition of asphalt. It was demonstrated that when the content of WPE in matrix asphalt was less than 10 wt%, the service performances of modified asphalt could be better.
Nanotechnology has been gradually penetrated into the field of asphalt modification. Seemingly magic effects of nanomaterials have now been brought to improve the performance of asphalt. To demonstrate many of the prospective applications, researchers have conducted a series of positive and effective efforts dealing with the preparation of modified asphalt to demonstrate the mechanism of modification and the resultant improvement in performance. In this review, various nanomaterials used in asphalt modification are initially presented, followed by the methods employed to modify the asphalt with these materials and finally the effects of nanomaterials on the performance of base asphalt are presented and the modification mechanisms are discussed. Based on the current research results, the influence of preparation process parameters on the compatibility of every phase in the modified asphalt and the stability of the modified asphalt system are described. Finally, the development trend of the topic field is projected.
