关键词: 橡胶粉,    ,  改性沥青,   ,  溶胀,   ,  降解,   ,  转化率

Abstract:        The influence of swelling and degradation process of the crumb rubber modified asphalt on the viscosity was investigated by analyzing the viscosity variation with the development time. And the mechanism was discussed through the degradation conversion of crumb rubber in asphalt as well. Three asphalts with different penetration grades were selected to test the viscosity variation due to the development time at different reaction temperatures, and the conversions of the crumb rubber were analyzed. The results show that the viscosity variation of the crumb rubber modified asphalt is mainly affected by the swelling and degradation reaction. At initial stage of the reaction, the swelling shows more influence on the viscosity variation than the degradation, but after the turning point, the degradation becomes the major factor. When the viscosity reaches stable state, it means the swelling and degradation of the crumb rubber finish. Increasing reaction temperature can accelerate the reaction speed of the swelling and degradation process of crumb rubber in the asphalt. Longer development time causes higher conversion. And higher reaction temperature results in the lower minimum viscosity and higher maximum conversion. It is proposed that the viscosity and the degradation conversion of crumb rubber modified asphalt could be controlled by selecting the optimized temperature and development time.

Key words: Crumb rubber,    , Modified asphalt,    , Swelling,    , Degradation,    , Degradation conversion