改性沥青广泛应用于道路工程建设,但微观层面上的沥青改性机理尚缺乏统一结论。采用分子动力学模拟方法,研究了四种聚合物改性剂分子与沥青分子之间的相互作用。基于基质沥青和改性沥青分子模型的溶解度参数、相互作用能及自由体积计算,解析了聚合物分子化学结构对沥青特性的影响。研究发现,沥青分子中芳香分含量越多,其溶解度参数与聚合物改性剂分子越接近;改性剂中存在杂原子,可对沥青分子起到一定的吸引作用;沥青模型加入改性剂分子后,自由体积有减小趋势,说明改性剂的加入,使部分沥青组分在改性剂周围产生了聚集效应,形成区域集中状态,沥青密度增大,稳定性增强。
Polymer modified asphalt is widely applied in pavement engineering due to the advanced process ability and performance.However,the molecular interaction between polymer modifier and asphalt is still unclear,and lead to there is no unified conclusion on the mechanism of modified asphalt.The interaction between four polymer modifiers and asphalt molecules was investigated by molecular dynamics simulation.The index including solubility parameters,interaction energy,free volume fraction and radial distribution function of matrix asphalt and modified asphalt model to illustrate the influence of polymer on the micro-structure and properties of asphalt.The results shown that the solubility parameters of asphalt approached to polymer modifier molecules with the increase of aromatics.The presence of heteroatom in the modifier molecule could influence in attracting the asphalt.The free volume of the asphalt model tended to decrease after adding the modifier molecule,indicating that asphalt molecules aggregated together due to the addition of modifier.Meanwhile,the density and stability of asphalt were increased.
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基金资助
材料工程重庆市研究生联合培养基地基金资助(201907)
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