Properties and modification mechanism of ZnO nanoparticle-modified asphalt

Zinc oxide (ZnO), as a modifier, can significantly improve some properties of asphalt. In this work, the spherical ZnO nanoparticles were synthesized using a solvothermal method. The ZnO nanoparticle-modified asphalt was prepared by means of a high shear mixer. The effects of the ZnO nanoparticles with different dosages on the permeability and softening point of the asphalt were investigated. The rheological properties of the asphalt with different ZnO dosage unaged and aged were evaluated and analyzed. The results show that the appropriate amount of the ZnO nanoparticles can improve the high-temperature performance of the asphalt, increase the softening point of the asphalt, reduce the penetration value of the asphalt, and enhance the rutting resistance of the asphalt. Compared with the original asphalt, when the amount of ZnO nanoparticles is 8%, the softening point of modified asphalt increases by 12.3% and the penetration value decreases by about 19%. The improvement of the performance of the ZnO nanoparticle-modified asphalt is the result of the synergistic effect of physical and chemical modifications.