PU-SBS复合改性沥青的高温性能试验研究

Experimental study on high temperature performance of PU-SBS composite modified asphalt

聚合物改性是提升沥青高温性能的重要途径。采用聚氨酯(PU)和苯乙烯—丁二烯—苯乙烯嵌段共聚物(SBS)制备一种复合改性沥青,研究引入PU-SBS对沥青高温性能的影响及改性机理。结果表明,PU-SBS复合改性显著降低了沥青的针入度,提高了软化点和黏度,有效提升了沥青的高温流变性能,改性效果明显优于单一聚合物改性。PU-SBS复合改性沥青在高温下有良好的抗永久变形能力和弹性恢复能力。64°C时,其车辙因子G*/sinδ值达到18.35 kPa,分别为同条件下SBS改性沥青、PU改性沥青的2.6、1.6倍。此外,PU-SBS复合改性主要通过聚合物在沥青中的吸附交联及与沥青组分的化学反应来提升沥青的高温性能。

Polymer modification is an important way to improve the high temperature performance of asphalt.In this work,PU-SBS composite modified asphalt was prepared by PU and SBS,and the effect of PU-SBS on high temperature performance of asphalt and modification mechanism were studied.The results show that PUSBS composite modification can significantly reduce the penetration of asphalt and improve the softening point.PU-SBS modified asphalt can effectively improve the viscosity and high temperature rheological properties of asphalt,and the modification effect is obviously better than that of single polymer modification.PU-SBS modified asphalt has good permanent deformation resistance and elastic recovery at high temperature.The rutting resistance factor G*/sinδat 64°C reaches 18.35 kPa,which is 2.6 times and 1.6 times of SBS modified asphalt and PU modified asphalt under the same conditions,respectively.In addition,PU-SBS composite modification combines physical and chemical modification to improve the high temperature performance of asphalt:physical adsorption swelling of SBS in asphalt and chemical reaction of PU with asphalt components.