高掺量胶粉-SBS复合改性沥青的高低温流变性能与微观机理

High and low temperature rheological properties and microscopic mechanism of high content rubber powder-SBS jointly modified asphalt

为研究高掺量胶粉对胶粉-SBS复合改性沥青流变性能的影响,首先采用三大指标和布氏旋转黏度确定了高掺量胶粉-SBS复合改性沥青的最佳胶粉掺量,再采用动态剪切流变(dynamic shear rheology,DSR)试验和弯曲梁流变(bending beam rheometer,BBR)试验评价了高掺量胶粉-SBS复合改性沥青在高低温条件下的流变性能,最后通过红外扫描试验和荧光显微镜试验分析了高掺量胶粉-SBS复合改性沥青的微观特征。结果表明:高掺量胶粉-SBS复合改性沥青在胶粉掺量为42%时的流变性能最佳;高掺量胶粉可以提高胶粉-SBS复合改性沥青的复数剪切模量、车辙因子和蠕变劲度,降低相位角和蠕变速率,使其高低温流变性能得到明显改善;胶粉-SBS复合改性在沥青中的改性过程主要为物理改性,并且胶粉脱硫后,其内部交联减少,在沥青中的分散效果更为均匀,可以使得高掺量胶粉与SBS在沥青中形成更为致密的交联结构,增强复合改性沥青的流变性能。

In order to study the effect of high content crumb rubber on rheological properties of crumb rubber-SBS jointly modified asphalt,the rubber powder content of high content rubber powder-SBS composite modified asphalt was optimized by three indexes and Brookfield rotational viscosity.Then,dynamic shear rheology(DSR)test and bending beam rheometer(BBR)test were used to evaluate the rheological properties of high content rubber powder-SBS jointly modified asphalt under high and low temperature conditions.Finally,the microscopic characteristics of high content rubber powder-SBS composite modified asphalt were analyzed by infrared scanning test and fluorescence microscope test.The results show that the best rheological properties of high content crumb rubber-SBS jointly modified asphalt can be obtained when the content of crumb rubber is 42%.High content of crumb rubber can improve the complex shear modulus,rutting factor and creep stiffness of crumb rubber-SBS composite modified asphalt,reduce the phase angle and creep rate,and improve the high and low temperature rheological properties obviously.The modification process of rubber powder-SBS composite modification in asphalt is mainly a physical modification.After desulfurization of rubber powder,the internal crosslinking of rubber powder is reduced,and the dispersion effect in asphalt is more uniform,leading to the formation of a denser crosslinking structure of high content rubber powder and SBS form in asphalt,and enhance the rheological properties of composite modified asphalt.