不同活化温度橡胶沥青微观结构特性与宏观性能联系研究

Study on Relationship between Microstructure Properties and Macro-mechanical Characteristics of Rubber Asphalt at Different Activation Temperatures

为探讨不同活化温度下橡胶改性沥青微观结构特性与宏观力学性能之间的联系,通过红外光谱试验,在常规性能试验、动态剪切流变试验以及多应力蠕变恢复试验的基础上,得到橡胶改性沥青的微观结构和宏观力学性能变化规律,建立两者之间的联系;并通过灰色关联分析,得到橡胶改性沥青不同活化温度与宏观力学性能和微观结构指标与宏观力学指标之间的关联程度。结果表明:在红外光谱下,胶粉的活化主要改变了橡胶改性沥青在1030 cm^-1和1600 cm^-1处亚砜基和丁二烯基两处官能团的伸缩振动区强度;随着活化温度的升高,红外光谱中亚砜基(S=O)和丁二烯基(C=C)指数逐渐降低,抗车辙因子(G*/sinδ)、蠕变回复率R3.2呈现逐渐降低的趋势,损耗因子(tanδ)、不可回复蠕变柔量Jnr3.2呈现逐渐升高的趋势。通过微观和宏观指标之间的关系模型可知,橡胶改性沥青S=O指数与宏观力学性能均有较好的相关性,其中与延度之间的线性相关性最好,可决系数R2为0.8880;C=C指数与135℃时布氏黏度的线性相关性最好,可决系数R2为0.9909,与针入度之间的相关性则较差。由灰色关联分析得到在活化温度为70℃时橡胶改性沥青的综合力学性能最优,S=O指数与135℃布氏黏度关联程度最好,C=C指数与软化点关联程度最好。

In order to explore the relationship between the microstructure properties and the macro-mechanical characteristics of rubber modified asphalt at different activation temperatures,on the basis of conventional performance testing,dynamic shear rheological test and multi-stress creep recovery test,the change rules of microstructure and macro-mechanical characteristics of rubber modified asphalt are obtained and the relationship between them is established through infrared spectrum test.The correlation degree of different activation temperatures with macro-mechanical characteristics and micro-structural indicators of rubber modified asphalt is obtained through grey correlation analysis.The result shows that(1)Under the infrared spectrum,the activation of the rubber powder mainly changed the strength of the stretching vibration zone of the sulfoxide group and the butadienyl group at 1030 cm^-1 and 1600 cm^-1 of the rubber modified asphalt respectively.(2)With the increase of activation temperature,the indicators of sulfoxide group(S=O)and butadienyl group(C=C)gradually decrease,the anti-rutting factor G*/sinδand the creep recovery rate R3.2 show the gradual decrease trend,while the loss factor tanδand the non-recoverable creep compliance Jnr3.2 show the gradually increase trend.(3)From the relationship model between micro and macro indicators,it can be seen that the S=O indicator of rubber modified asphalt has a good correlation with the macro mechanical characteristics,among them,S=O shows the best linear correlation with the ductility,and the determination coefficient R2 is 0.8880.The C=C indicator shows a best linear correlation with Brookfield viscosity at 135℃,and the determination coefficient R2 is 0.9909.It has a poor correlation with the penetration degree.(3)The gray correlation analysis shows that the comprehensive mechanical properties of rubber modified asphalt are the best when the activation temperature is 70℃.The S=O indicator has the best correlation with the Brookfield viscosity at 135℃,and the C=C indicator has the best correlation with the softening point.