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

摘要：         通过分析橡胶粉改性沥青黏度随发育时间的变化,探讨橡胶沥青体系的溶胀及降解过程对黏度的影响,并通过降解转化率的变化分析黏度变化的机理。研究选择了3种针入度等级的沥青,在不同的温度下测定橡胶粉改性沥青的黏度随发育时间变化曲线,并分析了橡胶粉降解转化率变化规律。结果表明,橡胶粉改性沥青黏度的变化主要受橡胶粉溶胀和降解过程的影响。在反应初期,橡胶粉的溶胀作用大于降解作用,到达转折点后,橡胶粉的降解作用大于溶胀作用,待黏度趋于平稳时,说明橡胶粉的溶胀和降解已经基本结束;提高反应温度,可以加快橡胶粉在沥青中的溶胀和降解反应过程;发育时间延长,转化率逐渐增加;反应温度越高,黏度下降的幅度越大,转化率的最高值越高。因此,可以通过选择合适的反应温度和发育时间,控制橡胶粉改性沥青的降解转化率和黏度范围。

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