基于粘弹性理论的天然沥青复合改性沥青低温流变性能

为优化天然沥青低温性能欠佳的问题,采用低温弯曲流变试验(BBR)对不同掺量下的橡胶/天然沥青及SBS/天然沥青复合改性沥青的低温性能进行试验,并结合Burgers模型对其蠕变数据进行拟合以分析天然沥青复合改性沥青的低温性能。结果表明：橡胶和SBS掺入使XRA和TLA天然改性沥青的粘性和弹性得到相应的改善,且其松弛时间逐渐减小,耗散能比与蠕变导数逐渐增加,低温下的应力松弛能力及弹性后效的到改善；在同一温度下,橡胶和SBS延缓了XRA与TLA到达蠕变稳定的时长,但随着温度的不断降低,其蠕变稳定时长逐渐减小。随着橡胶和SBS掺量的增加XRA和TLA复合改性沥青的低温性能有显著的提高,且橡胶对XRA和TLA天然改性沥青低温性能的改善优于SBS；随着温度的降低,不同掺量下的橡胶和SBS对其低温性能的改善程度逐渐减小。

Low temperature rheological properties of natural asphalt compound modified asphalt based on viscoelastic theory

In order to optimize the problem of low temperature performance of natural asphalt, low temperature bending rheology test (BBR) was used to test the low temperature performance of rubber/natural asphalt and SBS/natural asphalt composite modified asphalt with different contents and combined with Burgers model to fit the creep data and to analyze the low temperature performance of natural asphalt composite modified asphalt. The results showed that the rubber and SBS incorporation improved the viscosity and elasticity of XRA and TLA natural modified asphalt, and the relaxation time gradually decreased, the dissipation energy ratio and the creep derivative increased gradually, and the stress relaxation ability and elastic aftereffects at low temperature was improved. At the same temperature, rubber and SBS delay the time that XRA and TLA reach creep stability, but as the temperature decreases, the creep stability time gradually decreases. At the same temperature, rubber and SBS delay the time that XRA and TLA reach creep stability, but as the temperature decreases, the creep stability time gradually decreases. With the increase of rubber and SBS content, the low-temperature performance of XRA and TLA composite modified asphalt has improved significantly. And rubber improves the low temperature performance of XRA and TLA natural modified asphalt better than SBS. With the decrease of temperature, the improvement of the low temperature performance of natural asphalt is gradually reduced with rubber and SBS at different dosages.