SBS、橡胶和高黏改性沥青流变性能对比

Comparison of rheological properties between SBS, rubber and high-viscosity modified asphalt binders

为充分认识在同一评价体系中不同改性沥青高低温流变性能,使用动态剪切流变仪对SBS、橡胶和高黏改性沥青分别进行应变扫描试验,确定其线性黏弹性范围,进行频率扫描试验和多重应力蠕变恢复试验分析其高温性能。同时使用弯曲梁流变仪对3种改性沥青进行弯曲蠕变劲度试验分析其低温性能。研究结果表明:根据应变扫描试验结果,当应变小于10%时,SBS、橡胶和高黏改性沥青处在线性黏弹性范围内。根据频率扫描试验结果,使用Sigmoidal模型拟合SBS、橡胶和高黏改性沥青的复数剪切模量主曲线光滑连续,且均是简单的流变材料;SBS、橡胶和高黏改性沥青在低频状态下复数剪切模量相差较大,在高频状态下复数剪切模量相差较小。根据多重应力蠕变恢复试验结果,相比SBS和高黏改性沥青,橡胶改性沥青具有较高的流动变形特性;高黏改性沥青的抗永久变形能力优于橡胶和SBS改性沥青。低温弯曲蠕变劲度试验中,蠕变劲度和蠕变速率均与温度呈指数关系。通过蠕变劲度和蠕变速率可知,高黏改性沥青的低温抗裂性优于SBS和橡胶改性沥青。此外,用蠕变劲度指数衡量改性沥青的低温感温性,可知高黏改性沥青温度敏感性低于SBS和橡胶改性沥青温度敏感性。因此,在流变性能方面,高黏改性沥青的高低温性能均优于SBS和橡胶改性沥青。

To fully understand the high-and low-temperature rheological properties of different modified asphalt binders in the same evaluation system,a dynamic shear rheometer was used to conduct a strain sweep test to determine the linear viscoelastic range of styrene-butadiene-styrene(SBS)modified asphalt binder,rubber modified asphalt binder,and high-viscosity modified asphalt binder.This rheometer was also utilized to perform the frequency sweep test and multiple stress creep recovery tests to analyze their high-temperature properties.Meanwhile,a bending beam rheometer was used to carry out bending creep stiffness tests to analyze their low-temperature properties.The results show that according to the strain sweep test,the SBS,rubber,and high-viscosity modified asphalt binders are within the range of linear viscoelasticity at less than 10%strains.Based on the frequency sweep test result,their complex shear modulus main curves fitted by the Sigmoidal model are smooth and continuous,they are all simple rheological materials.There are great differences in the complex shear moduli of the SBS,rubber,and high viscosity modified asphalt binders at low frequencies.These differences are relatively small at high frequencies.The multiple stress creep recovery test result shows that compared with the SBS and high-viscosity modified asphalt binders,the rubber modified asphalt binder has larger flow deformation characteristics.Furthermore,the high-viscosity modified asphalt binder has better resistance to permanent deformation than rubber and SBS modified asphalt binders.According to the low-temperature bending creep stiffness test result,both creep stiffness and creep rate are exponentially related to temperature.Through the creep stiffness and creep rate,it is determined that the low-temperature cracking resistance of the high-viscosity modified asphalt binder is better than that of SBS and rubber modified asphalt binders.Furthermore,the result of low-temperature sensitivity assessed by the creep stiffness index demonstrates that the temperature sensitivity of the high-viscosity modified asphalt binder is smaller than that of SBS and rubber modified asphalt binders.Therefore,the high-and low-temperature rheological behaviors of the high-viscosity modified asphalt binder are superior to those of the SBS and rubber modified asphalt binders.3 tabs,10 figs,29 refs.