长期高温多雨环境下沥青与集料黏附性衰减规律研究

选用2种沥青及3种集料，对单个集料进行不同时长的改进水煮法试验，对松散沥青混合料进行不同时长的改进ASTM D3625水煮法试验。通过扫描电镜试验、能谱分析试验分析集料表面构造和化学成分；通过高温接触角试验，获取拌和温度下集料与沥青的接触特性。结合质量法和图像法，分析沥青-集料的剥落率，探究在长时间高温水煮条件下的沥青-集料黏附性的衰减规律。结果表明：石灰岩与沥青的黏附性最好，砂岩最差；采用SBS改性沥青可有效增加与集料的黏附性，降低沥青-集料黏附性的衰减；水煮时间增长，使用Si元素含量越高、接触角越大的集料，沥青-集料黏附性越差；仅通过水煮样品3分钟来评价样品的黏附性不准确，延长水煮时间并结合质量分析方法可更真实地表征黏附性变化；对长期高温多雨地区，推荐使用石灰岩和SBS改性沥青来提高沥青混合料的抗水损害能力。

Study on Adhesion Attenuation Law between Asphalt and Aggregate under Long-term High Temperature and Rainy Environment

Two kinds of asphalt and three kinds of aggregates were selected in this study. The modified water boiling test for single aggregate and the modified ASTM D3625 water boiling test for loose asphalt mixture with different duration were performed. The scanning electron microscope test, the energy dispersive spectrum analysis test were carried out to explore the surface structure and chemical composition of aggregates. The high temperature contact angle test was carried out to explore the contact characteristics between aggregate and asphalt at the mixing temperature. Combined with the mass method and the image method, the asphalt-aggregate stripping rate was analyzed, and the attenuation law of adhesion between asphalt and aggregates under long-time high-temperature boiling condition was explored. The results showed that the adhesion between limestone and asphalt is the best and that of sandstone is the worst. SBS modified asphalt can increase the adhesion with aggregate and effectively reduce the attenuation of adhesion. The longer boiling time, the higher the content of Si and the larger the contact angle of aggregate, the worse the asphalt-aggregate adhesion. It is not accurate to determine the adhesion only by boiling the single aggregate for 3 minutes. The adhesion can be truer reflected by prolonging the boiling time and using the mass method. For long-term high temperature and rainy areas, limestone and SBS modified asphalt are recommended to improve the water damage resistance of the asphalt mixture.