SMC常温改性沥青低温及微观性能评价

Evaluation of low temperature and microproperties of SMC modified asphalt

为了研究甲基苯乙烯类嵌段共聚物(styreneic methyl copolymers,SMC)常温改性沥青宏观和微观下的低温流变性能,通过低温弯曲梁流变仪(bending beam rheometer,BBR)、傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)和原子力显微镜(atomic force microscope,AFM)对SMC常温改性沥青的低温性能进行测试,探究SMC常温改性剂对沥青的改性机理;与苯乙烯-丁二烯-苯乙烯嵌段共聚物(styrene-butadiene-styrene,SBS)改性沥青和基质沥青的低温流变性能进行对比,探究3种沥青低温流变性能的差异并给出寒冷地区最适宜的沥青类型。结果表明:SMC常温改性沥青的低温性能优于SBS改性沥青和基质沥青,基于Burgers模型计算得到的低温综合柔量(J c)能很好地描述沥青的低温性能,推荐使用。此外,SMC改性剂对基质沥青主要以物理改性为主;通过AFM测定的形貌发现,SMC常温改性沥青未出现明显的“蜂形结构”,SMC改性剂的加入使沥青的均方根粗糙度减小,沥青相态差异性变小,DMT模量降低。SMC常温改性沥青推荐用于寒冷地区。

In order to study the low temperature rheological properties of styreneic methyl copolymers(SMC)and the SMC normal temperature modified asphalt at macro and micro levels,the low temperature performance of SMC normal temperature modified asphalt was tested by low temperature bending beam rheometer(BBR)test,Fourier transform infrared spectroscopy(FTIR)and atomic force microscope(AFM),and the modification mechanism of SMC normal temperature modified asphalt was explored.Compared with the low temperature rheological properties of styrene-butadiene-styrene(SBS)modified asphalt and matrix asphalt,the difference of low temperature rheological properties of three kinds of asphalt was explored and the most suitable asphalt type in cold region was found.The results show that the low temperature performance of SMC normal temperature modified asphalt is better than those of the SBS modified asphalt and the matrix asphalt.The low temperature comprehensive flexibility(J c)calculated based on Burgers model can describe the low temperature performance of asphalt well,and it is recommended.In addition,the SMC normal temperature modified asphalt is mainly modified physically.The morphology map determined by AFM shows that SMC normal temperature modified asphalt has no obvious“bee structure”,and the addition of SMC modifier reduces the root mean square roughness of asphalt,the difference of asphalt phase and the DMT modulus.The SMC normal temperature modified asphalt is recommended for cold areas.