沥青自愈合性能评价指标修正及应用

通过对比和分析现有沥青自愈合指标的不足，以模量下降速率重新定义自愈合指标，该指标值越小说明沥青材料的自愈合性能越优。采用动态剪切流变仪（Dynamic Shear Rheometer，DSR）对7种沥青进行不同间歇时间和不同损伤度下间歇加载式的自愈合试验，以毛细扩散理论下的自愈合行为方程对自愈合指标进行线性拟合，获得代表沥青瞬时自愈合和后期自愈合的参数，用以研究沥青的自愈合性能。结果表明：沥青的自愈合指标随着间歇时间的增大而减小，但其变小的速率趋于缓慢；7种沥青在不同损伤度下的自愈合指标值与间歇时间的0.25次方存在较好的线性正相关，判定系数R²均在0.85以上，无论是基质沥青还是改性沥青，新指标都具有较好的适用性；SBS改性沥青的瞬时自愈合优于基质沥青，随着添加到SBS沥青中改性剂掺量的增大，改性沥青的瞬时自愈合表现出先弱后强的趋势，而这7种沥青的后期自愈合性能与其瞬时自愈合性能正好相反，代表瞬时自愈合和后期自愈合的参数具有较好的负相关，说明瞬时自愈合性能优的沥青其后期自愈合性能较差。

Correction and Application of Self-healing Performance Index of Asphalt Binder

By comparing and analyzing the insufficiency of existing asphalt self-healing indicators, the self-healing index of asphalt was redefined at the rate of modulus decline. A smaller value of this index results in better self-healing performance of asphalt. Seven types of asphalt were subjected to fatigue-healing test with intermittent loading under different time and damage degrees by Dynamic Shear Rheometer (DSR). According to the equation of self-healing behavior of capillary diffusion, the self-healing index was linearly fitted. The parameters representing instantaneous and after-loading self-healing of asphalt were obtained to study the self-healing properties of asphalt. The results show that the self-healing index of asphalt decreases with an increase in intermittent time but the rate of its decrease tends to be slow. Linear and positive correlations were found between the self-healing index values of the seven types of asphalt under different damage degrees and a quarter of the intermittent time. All values of R² are greater than 0.85, indicating that the new index is applicable to both matrix and modified asphalt. The instantaneous self-healing of SBS modified asphalt was found to be better than that of matrix asphalt. When the modifier content added to SBS asphalt was increased, the instantaneous self-healing of modified asphalt first became weak and then strengthened. The after-loading self-healing performance of asphalt is contradictory to its instantaneous self-healing performance. It represents a negative correlation between the parameters of instantaneous self-healing and after-loading self-healing, thereby indicating that asphalt with excellent instantaneous self-healing properties has poor after-loading self-healing properties.