Rheological properties and microscopic mechanism of waste cooking oil activated waste crumb rubber modified asphalt

In this paper, the surface activated crumb rubber with waste cooking oil (WCO) was studied to improve the performance of crumb rubber modified asphalt. The activated waste crumb rubber modified asphalt (OCRMA) with different amount of crumb rubber was prepared to study the microscopic appearance of OCRMA by scanning electron microscope and fluorescence microscope and analyze the surface performance. The rheological properties and microscopic mechanism of OCRMA were characterized by dynamic shear rheological test, multiple stress creep recovery (MSCR) test, BBR test and infrared spectroscopy. The results show that the dissolution degree of waste crumb rubber is improved after WCO activation, and the compatibility with asphalt components is enhanced, and the stable cross-linking structure is formed, which improves the asphalt performance. The several new absorption peaks, which were obvious, were all caused by the composition of WCO, that is, there was no significant chemical change during the interaction between the activated crumb rubber and base asphalt. Compared with the common waste crumb rubber modified asphalt (CRMA), activation with WCO can significantly reduce the viscosity of CRMA, decrease the difference of segregation softening point by 27%, and enhance the low temperature performance by 30%. The aging degree is greatly reduced, and the anti-aging performance of OCRMA is increased by about 20% with the same dosage. The high temperature performance, though higher than that of base asphalt, decreases to some extent. After comprehensive analysis, the optimal dosage of crumb rubber for OCRMA is 30%.