DCLR改性沥青的流变力学性质

为研究煤直接液化残渣（DCLR）改性沥青的流变力学性质并评价其改性效果，采用动态剪切流变仪对90^#基质沥青（改性前）和DCLR改性沥青（改性后）进行温度频率扫描试验、多重应力蠕变恢复（MSCR）试验和不同应力水平下的时间扫描试验，分别评价其强度、抵抗永久变形的能力和抵抗疲劳开裂的能力。结果表明：DCLR改性沥青在低频范围（10^-3～10³ rad·s^-1）内的动态剪切模量大于90^#基质沥青，在高频范围（10³～10⁶ rad·s^-1）内的动态剪切模量略小于90^#基质沥青，整体上DCLR改性沥青的强度高于90^#基质沥青，且在同一频率范围内其动态剪切模量变化幅度变小，说明改性后其温度敏感性降低；通过对比DCLR改性沥青和90^#基质沥青在不同温度下的未恢复蠕变柔量和恢复率，发现同一温度下DCLR改性沥青的未恢复蠕变柔量均低于90^#基质沥青，恢复率均高于90^#基质沥青，说明DCLR改性沥青抵抗永久变形的能力和变形恢复的能力相较于90^#基质沥青有显著提高；通过对比分析这2种沥青在不同应力水平下的疲劳寿命，发现DCLR改性沥青的疲劳寿命显著高于90^#基质沥青，证明其抵抗疲劳开裂的能力相较于90^#基质沥青更好，这2种沥青的疲劳寿命随应力水平的变化规律均能采用幂函数进行拟合，且拟合效果良好。

Rheological Mechanical Properties of DCLR-modified Asphalt Binders

To investigate the rheological mechanical properties and evaluate the effect of modification of direct-coal-liquefaction residue (DCLR)-modified asphalt binders, the dynamic shear rheometer (DSR) was employed to perform the time and temperature sweep tests, multiple stress creep and recovery (MSCR) tests, and time sweep tests at different stress levels on 90^# base binders (before modification) and DCLR-modified binders (after modification). These tests were used to evaluate the stiffness, permanent deformation resistance, and fatigue cracking resistance of DCLR-modified binders, respectively. The results indicate the following. 1) The dynamic shear modulus of DCLR-modified binders is higher/lower than that of 90^# base binders at low/high frequency; overall, the stiffness of DCLR-modified asphalt binders is higher than that of 90^# base binders and the stiffness of DCLR-modified binders decreases less significantly than that of 90^# base binders, which suggest reduced temperature susceptibility of DCLR-modified binders. 2) By comparing the nonrecoverable creep compliance and percent recovery of DCLR-modified binders and 90^# base binders at different temperatures, it is observed that the nonrecoverable creep compliance of DCLR-modified binders is less and the percent recovery is greater than that of 90^# base binders at the same temperature, which indicates that the permanent deformation resistance and recovery potential of DCLR-modified binders are significantly better than that of 90^# base binders. 3) By comparing the fatigue lives of two binders at different stress levels, the resistance to fatigue cracking of DCLR-modified binders is observed to be greatly enhanced compared to that of 90^# base binders; moreover, the power function can be employed to illustrate the variation of fatigue life with stress levels for both asphalt binders with satisfactory goodness of fit.