Abstract: The adhesion performance at the bitumen-aggregate interface is a critical factor in mitigating pavement water damage, as it directly influences the service life of road infrastructure. To address the limitations of conventional modifiers, such as high costs and complex processing, low-molecular-weight polyolefin was employed as a modifier for bitumen mixtures in this research. By proposing a hierarchical research methodology that integrated microscopic wetting behavior, interfacial energy optimization, and macroscopic performance validation. This study overcomed the traditional single-scale limitations and achieved systematic innovation from microscopic mechanisms to macroscopic performance. A comprehensive approach combining contact angle measurements, surface energy analysis, and interfacial energy parameters (adhesion work, Was; spalling work, Wasw; energy ratio, ER) was utilized to investigate the effects of polyolefin dosage (2wt%~8wt%) on the interfacial interactions between bitumen and three lithological aggregates (granite, basalt, limestone). Multivariate regression analysis and modified boiling water tests were further conducted to validate the adhesion enhancement mechanisms. The experimental results demonstrated that low-molecular-weight polyolefin significantly reduced bitumen contact angles (8%~58%), thereby improving wettability and interfacial bonding. Was increased by 38.3% to 39.5%, ER increased by 1.38 to 1.41 times, and Wasw decreased to -94.86~-97.85 mJ/m2, collectively confirming enhanced interfacial stability. The optimal polyolefin dosage varied with aggregate lithology: granite, basalt, and limestone achieved the minimal Wasw values (-97.85, -96.15, and -94.86 mJ/m2) at dosages of 2wt%, 4wt%, and 6wt%, respectively. Correlation analysis revealed a strong positive relationship between polyolefin dosage and ER (correlation coefficient=0.90, p<0.01), which outweighs the influence of aggregate oxide composition and underscoring the dominant role of polyolefin in adhesion enhancement. Experimental validation showed a 34% reduction in the spalling rate (Wb) and a significant improvement in water stability. This research provides a theoretical foundation and technical support for the application of low-molecular-weight polyolefin in bitumen pavement engineering.

Key words: bitumen, interfacial adhesion, polyolefin, surface energy, contact angle

摘要： 沥青-集料界面黏附性能是控制路面水损害的关键因素，直接影响道路服役寿命。针对传统改性剂成本高、工艺复杂等问题，本研究创新地采用低分子量聚烯烃作为沥青混合料改性剂，通过接触角测量、表面能计算及界面能参数(黏附功Was、剥落功Wasw、能量比ER)的多维度分析，系统研究了聚烯烃掺量(2wt%~8wt%)对石油沥青与花岗岩、玄武岩、石灰岩三种典型岩性集料界面性能的影响规律，并采用多元回归分析和改良水煮法验证了其黏附增强效应。研究结果表明，低分子量聚烯烃可显著降低沥青的接触角(8%~58%)，使沥青-集料界面间的Wasw提升38.3%~39.5%、ER增加1.38~1.41倍，同时将Wasw降低至-94.86~-97.85 mJ/m2，有效改善了沥青润湿性和黏附性能。集料岩性差异导致聚烯烃最佳掺量分化，花岗岩、玄武岩与石灰岩分别在2wt%, 4wt%与6wt%掺量时达到最小Was值(-97.85, -96.15, -94.86 mJ/m2)。相关性分析显示，聚烯烃掺量与ER的相关系数达0.90 (p<0.01)，显著高于集料氧化物调控作用，证实其主导沥青黏附性能提升。实验验证表明，改性后沥青的剥落率Wb降低34%，水稳定性提升显著。研究结果为低分子量聚烯烃在沥青路面工程中的应用提供了理论依据与技术支撑。

关键词: 沥青, 界面黏附性, 聚烯烃, 表面能, 接触角