沥青零剪切黏度与高温流变参数灰色关联分析

Grey Correlation Analysis of Zero Shear Viscosity and High Temperature Rheological Parameters of Asphalt

采用动态频率扫描试验和稳态剪切试验测试5种沥青的黏度曲线,并采用Cross模型和Carreau模型这2种流变模型拟合得到沥青60℃零剪切黏度,分析沥青的稳态流动特性;通过沥青温度扫描试验和多重应力蠕变恢复试验,测定5种沥青在不同温度下的流变参数和不同应力水平下的不可恢复蠕变柔量及不可恢复蠕变柔量差,并对5种沥青零剪切黏度与高温流变参数进行灰色关联分析.结果表明:与动态频率扫描试验相比,稳态剪切试验更加适合用来测定基质沥青和改性沥青的零剪切黏度;Cross模型和Carreau模型均可较好拟合5种沥青的零剪切黏度,Carreau模型的拟合值小于Cross模型;相比于其他沥青高温流变参数和不可恢复蠕变柔量,沥青不可恢复蠕变柔量差与零剪切黏度的灰色关联度最高,能更好地反映沥青的高温性能;随着温度的升高,沥青车辙因子与零剪切黏度的灰色关联度逐渐增大;沥青零剪切黏度与不可恢复蠕变柔量差及车辙因子的关联性最好,3个指标均能较好地评价沥青高温性能.

The viscosity curves of five asphalts were tested by dynamic frequency scanning and steady-state shearing.Zero shear viscosity of different asphalt samples at 60℃was fitted by Cross and Carreau rheological models.The steady flow characteristics of asphalts were analyzed.The temperature scanning test and multiple stress creep recovery test were carried out to obtained the viscoelastic parameters of asphalts at different temperatures and different stress levels.And the grey correlation analysis was carried out between zero shear viscosity and the high temperature rheological parameters of asphalts.The results show that the steady-state shearing test is more suitable for zero shear viscosity determination of matrix asphalt and modified asphalts than the dynamic frequency scanning test.Both Cross and Carreau rheological models can fit five asphalts zero shear viscosity well,and the fitting value of Carreau model is less than that of Cross model.Compared with other viscoelastic parameters and non-recoverable creep compliance,the grey correlation degree between non-recoverable creep compliance difference and zero shear viscosity of asphalt is the highest,which better reflects the high temperature performance of asphalt,and the grey correlation degree between rutting factor and zero shear viscosity of asphalt increases with the increase of temperature.Asphalt zero shear viscosity has the best correlation with non-recoverable creep compliance difference and rutting factor,and all three indicators are good for evaluating asphalt high temperature performance.