基于表面自由能研究水温耦合作用对沥青黏结性能的影响

Study on the Effect of Water Temperature Coupling on Asphalt Bond Performance Based on Surface Free Energy

为研究水温耦合作用对沥青表面能及其与集料黏附性能的影响,采用静滴法测定3种测试液体与玄武岩以及高温水浴、冻融循环2种水温耦合条件作用前后SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)改性沥青和高黏沥青(HVA)的接触角,基于表面自由能理论,分析水温耦合前后不同沥青的表面能、黏聚功及其与集料的黏附功,同时通过大空隙沥青混合料浸水飞散试验验证不同沥青与集料的黏结性能。结果表明,水温耦合作用降低了沥青的表面能、黏聚功和沥青-集料界面的黏附功;相较于冻融循环,高温水浴的影响更大。高黏沥青抵抗水温耦合作用的性能要优于SBS改性沥青。大空隙沥青混合料肯塔堡飞散损失表征的不同沥青与集料的黏结性能试验结果与表面自由能计算结果一致,沥青的表面能可以很好地解释沥青混合料的抗松散能力。水温耦合作用下,沥青-集料界面的黏附功受沥青性质的影响显著,使用高黏沥青可显著提升黏附功,在水稳定性要求苛刻的地区推荐采用高黏沥青作为沥青混合料的胶结料。

In order to study the effect of water temperature coupling on the surface energy of asphalt and its adhesion to aggregate,the contact angles of basalt,SBS modified asphalt and high viscosity asphalt(HVA)with three test liquids were measured by sessile drop method before and after high temperature water bath and freeze-thawing cycle.Then,based on the surface free energy theory,the surface energy and cohesion work of different asphalt,the adhesion work with aggregate before and after the water temperature coupling were analyzed.At the same time,the adhesion performance of different asphalt and aggregate was verified by the water immersion and dispersion test of large void asphalt mixture.The results showed that the water temperature coupling reduced the surface energy,the cohesiveness and the adhesion of the asphalt-aggregate interface,and the effect of high temperature water bath was greater than that of freeze-thaw cycle.The resistance performance of HVA to the coupling effect of water temperature was better than that of SBS modified asphalt.Test results of adhesion performance between different asphalt and aggregate represented by Cantabro loss of large void asphalt mixture test were consistent with the calculated results of surface free energy.The surface energy of asphalt can well explain the anti-loosening ability of asphalt mixture.Under the coupling effect of water temperature,the adhesion work of asphalt-aggregate interface was more significantly affected by the properties of asphalt,and the use of high viscosity asphalt can significantly improve the adhesive power.It is recommended to use high viscosity asphalt as the binder of asphalt mixture in the areas with severe water stability requirements.