基于分子动力学的聚氨酯改性沥青自愈合行为研究

Study on Self-healing Behavior of Polyurethane Modified Bitumen Based on Molecular Dynamics

文中采用分子动力学方法建立了基质沥青和PU改性沥青自愈合模型.通过密度、能量、温度,以及Z轴浓度曲线研究了PU改性沥青的自愈合行为.通过扩散系数、自由体积分数和氢键分析了PU对沥青自愈合的影响.结果表明:PU改性沥青的自愈合行为分为:能量获取、流动扩散、自愈合,以及分子平衡四个阶段.当温度相同时,PU对沥青的自愈合有促进作用.PU与沥青分子间氢键的形成,使愈合结束的模型强度更高.

The self-healing model of matrix asphalt and PU modified asphalt was established by molecular dynamics method.The self-healing behavior of PU modified asphalt was studied by density,energy,temperature and Z-axis concentration curves.The influence of PU on asphalt self-healing was analyzed by diffusion coefficient,free volume fraction and hydrogen bond.The results show that the self-healing behavior of PU modified asphalt can be divided into four stages:energy acquisition,flow diffusion,self-healing and molecular balance.When the temperature is the same,PU can promote the self-healing of asphalt.Meanwhile,the formation of hydrogen bonds between PU and asphalt molecules makes the model with the end of healing stronger.