基于分子模拟的沥青胶结料物理老化机理研究

Physical Aging Mechanism of Asphalt Binder Based on Molecular Simulation

利用Materials Studio软件建立沥青的四组分模型,利用体积温度曲线得到了该沥青模型的玻璃化转变温度,同时利用差示扫描量热(DSC)试验验证了沥青模型所得玻璃化转变温度的可靠性,并在低于玻璃化转变温度下利用分子动力学从微观上对沥青分子的物理老化现象进行模拟与分析.结果表明:在低于沥青玻璃化转变温度的等温等压条件下,沥青模型随着时间的延长,出现了自由体积减小、密度增大的物理老化现象;低温下沥青质和胶质导致沥青活动性降低,出现了物理老化现象,实现物理老化的微布朗运动的分子活动力主要来自饱和分和芳香分.

The four-component model of asphalt was established by Materials Studio software,and the glass transition temperature of the asphalt model was calculated by volume-temperature curve.The differential scanning calormetry(DSC)test was used to prove the reliability of the glass transition temperature of the asphalt model.At a temperature below the glass transition temperature,molecular dynamics was used to simulate and analyze the physical aging of asphalt molecules from the microscopic level.The results show that under the isothermal and isobaric conditions below the glass transition temperature of asphalt,the asphalt model exhibits a physical aging phenomenon with reduced free volume and increased density over time.At the same time,asphaltene and resin at low temperatures cause physical degradation of asphalt activity,and the molecular activity of micro-Brown movements mainly comes from saturated and aromatic components.