Study on performance and microscopic mechanism of hydrogen peroxide treated waste crumb rubber modified asphalt

The application of waste crumb rubber to modified asphalt can not only improve pavement performance, but also make full use of renewable resources, which is of great significance to environmental protection. However, the waste crumb rubber modified asphalt has some disadvantages such as poor storage stability, high viscosity and high construction temperature requirement, which restricts the application of crumb rubber modified asphalt in road engineering. In order to improve the storage stability and construction workability of waste crumb rubber modified asphalt, in this paper hydrogen peroxide is adopted for the surface oxidation treatment of waste crumb rubber, to prepare five kinds of hydrogen peroxide treated waste crumb rubber modified asphalt with waste crumb rubber dosage of 15%, 20%, 25%, 30%, and 35% (wt%). The pavement performance was studied by conventional performance tests and rheological properties tests. Then, the microscopic mechanism was studied by scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis. The results show that the waste crumb rubber becomes fluffy and has a richer pore structure on the surface after hydrogen peroxide treatment, which makes it easier for the light components in the asphalt to penetrate into the waste crumb rubber, and thus promotes its dissolution in asphalt, thereby improving the storage stability, construction workability, and low temperature performance of waste crumb rubber modified asphalt, but reduces the high temperature and elastic properties. At the same time, the surface polarity of activated waste crumb rubber is enhanced, and esterification reaction occurs with carboxyl groups, sulfoxides and acid anhydrides in asphalt, which effectively increases the interface bonding between asphalt and the waste crumb rubber, and further improves the storage stability, construction workability and low temperature performance of the waste crumb rubber modified asphalt. The optimum dosage of waste crumb rubber modified asphalt treated with hydrogen peroxide is 30%.