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Abstract：
To evaluate the thermal stability of composite polymer-modified asphalt, thermoplastic elastomer styrene-butadiene rubber (SBR)/polypropylene (PP) pellets were prepared using a hot-melt blending technique, with butyl rubber powder and waste polypropylene pellets as raw materials. The effects of different evaluation indexes on the thermal stability of SBR/PP-modified asphalt were investigated using a frequency scan test and a multi-stress creep recovery (MSCR) test, and the compatibility of SBR/PP particles with asphalt was studied using the Cole-Cole diagram and microstructure images. The tests show that, firstly, the performance grade (PG) classification of asphalt can be improved by adding an SBR/PP thermoplastic elastomer to enhance the adaptability of asphalt in high- and low-temperature environments, and the evaluation separation index can reflect the high-temperature storage stability of composite-modified asphalt more reasonably. Additionally, the larger the rubber-to-plastic ratio the worse the high-temperature thermal stability of composite-modified asphalt. Moreover, the addition of additives to the composite particles can promote the SBR/PP particles in the asphalt to be more uniformly dispersed, forming a more desirable microstructure and improving the thermal stability of composite-modified asphalt. Ultimately, the semicircular curve of the Cole-Cole diagram can reflect the compatibility characteristics of the two-phase structure of SBR/PP-modified asphalt, which can be used as an auxiliary index to evaluate the compatibility of polymer-modified asphalt.
摘要：
为评价复合聚合物改性沥青的热稳定性,热塑性弹性体丁苯橡胶（SBR）/聚丙烯（PP）颗粒使用热熔共混技术制备，以丁基橡胶粉和废聚丙烯颗粒为原料。采用频率扫描试验和多应力蠕变恢复(MSCR)试验,研究了不同评价指标对SBR/PP改性沥青热稳定性的影响,使用Cole-Cole图和微观结构图像研究了SBR/PP颗粒与沥青的相容性。测试表明,首先,加入SBR/PP热塑性弹性体可以提高沥青的性能等级(PG)等级,增强沥青在高低温环境下的适应性,评价分离指标能更合理地反映复合改性沥青的高温储存稳定性。此外,胶塑比越大,复合改性沥青的高温热稳定性越差。此外，在复合颗粒中加入添加剂可以促进SBR/PP颗粒在沥青中更均匀地分散,形成更理想的微观结构，提高复合改性沥青的热稳定性。最终,Cole-Cole图的半圆形曲线可以反映SBR/PP改性沥青两相结构的相容性特征,可作为评价聚合物改性沥青相容性的辅助指标。
