基于分子动力学两集料间沥青的拉伸黏附机理

Tensile Adhesion Mechanism of Asphalt Confined in Two Aggregates Based on Molecular Dynamics

基于分子动力学(MD)模拟,建立了两集料间沥青的模型,研究了拉伸速率、温度对沥青-集料界面拉伸应力-位移曲线的影响,从原子尺度分析了沥青-集料界面的拉伸破坏形式和黏附机理,同时通过拟合拉伸应力-位移曲线,提出了适用于宏观数值分析的内聚力模型.结果表明:当拉伸应力超过应力峰值后,沥青-集料的破坏由以黏附破坏为主转变为以黏聚破坏为主;拉伸速率越大,应力峰值越大;温度越高,应力峰值越小;沥青在拉伸应力达到应力峰值之前保持弹性状态,此时变形可逆,当拉伸应力超过应力峰值后,受到的损伤不可逆.

Based on molecular dynamics(MD)simulation,a model of asphalt confined in two aggregates was constructed,and the effects of tensile rate and temperature on the tensile stress-displacement curve of asphalt-aggregate interface were studied.The tensile failure mode and adhesion mechanism of asphalt-aggregate interface were analyzed in atomic nanoscale.By fitting the tensile stress-displacement curves,the cohesive model for macro numerical analysis was proposed.The results show that the failure of asphalt-aggregate changes from adhesive failure to cohesive failure when the tensile stress exceeds the peak stress.The peak stress increases with the tensile velocity and decreases with the temperature.Before the tensile stress reaches the peak stress,the asphalt remains in an elastic state,and the deformation is reversible.When the tensile stress exceeds the peak stress,the damage is irreversible.