餐饮废油对老化沥青的微观再生效应  

Microscopic regeneration effect of catering waste oil on aged asphalt

作　　者：徐宁 汪海年[1] 陈玉[1] 王惠敏 焦虎 XU Ning;WANG Hainian;CHEN YU;WANG Huimin;JIAO Hu(School of Highway,Chang’an University,Xi’an 710064,China)

机构地区：[1]长安大学公路学院,陕西西安710064

出　　处：《铁道科学与工程学报》2023年第9期3406-3415,共10页Journal of Railway Science and Engineering

基　　金：国家重点研发计划项目(2021YFB2601000)。

摘　　要：为了从分子水平揭示餐饮废油(CWO)对老化沥青的再生机制,利用分子动力学和密度泛函理论方法分析CWO对老化沥青胶体性质的影响。通过溶解度参数和密度验证了构建的基质沥青,老化沥青及CWO再生沥青模型的合理性。从径向分布函数和沥青质二聚体结构角度探讨了加入CWO前后老化沥青胶体结构的演化规律及成因;从内聚能密度,剪切黏度,玻璃化转变温度角度表征了CWO对老化沥青胶体热力学性质的恢复效果。结果表明,老化破坏了沥青的溶-凝胶体结构,使其内部形成了致密的沥青质分子团聚。CWO发挥了解缔沥青质团聚的作用,部分恢复了老化沥青胶体的微观结构。与老化沥青质二聚体随机接触的CWO小分子占据了部分结合空间,通过物理空间阻隔使老化沥青质二聚体的结合距离由3.894Å增加至4.773~5.044Å之间,而结合能由68.482 Kcal/mol降低至40.157~55.376 Kcal/mol之间。与含氧端部相比,CWO分子的不含氧端部和中部更显著地削弱了老化沥青质二聚体的结合强度。CWO恢复了老化沥青胶体的微观结构,降低了老化沥青分子间的作用强度,一定程度上扭转了老化对沥青性能的负面影响,表现为CWO再生沥青的剪切黏度和玻璃化转变温度等热力学性质得到改善。研究成果有利于深入认识CWO对老化沥青的再生机制,也进一步证明了CWO作为老化沥青再生剂的潜力。To reveal the regeneration mechanism of catering waste oil(CWO)on aged asphalt from the molecular level,the effects of CWO on the colloidal properties of aged asphalt were analyzed by means of molecular dynamics and density functional theory methods.The constructed models of base asphalt,aged asphalt and CWO recycled asphalt were validated by solubility parameters and density.The evolution of the colloidal structure of aged asphalt before and after CWO addition was investigated in terms of the radial distribution function and asphaltene dimer structure;the recovery effect of CWO on the colloidal thermodynamic properties of aged asphalt is characterized in terms of cohesive energy density,shear viscosity and glass transition temperature.The results show that aging destroys the sol-gel structure of the asphalt and causes the formation of compact asphaltene molecular agglomerates.CWO plays a role in declustering asphaltene agglomerates and partially restores the colloidal microstructure of aged asphalt.Small CWO molecules contacting randomly with aged asphaltene dimers occupy part of the binding space and increase the binding distance of aged asphaltene dimers from 3.894Åto a range of 4.773~5.044Åby physical space barrier while reducing the binding energy from 68.482 Kcal/mol to a range of 40.157~55.376 Kcal/mol.Compared with the oxygen-containing end,the nonoxygen-containing end and middle part of CWO molecules weaken the binding strength of aged asphaltene dimers more significantly.With the restoration of the colloidal microstructure and the reduction of the intermolecular interaction strength of the aged asphalt,CWO has reversed the negative effects of aging on asphalt properties to a certain extent,as shown by the recovery of shear viscosity and glass transition temperature of CWO recycled asphalt.The findings are beneficial to the in-depth understanding of the regeneration mechanism of CWO on aged asphalt and further demonstrate the potential of CWO as a rejuvenator for aged asphalt.

关 键 词：道路工程 分子模拟 老化沥青 餐饮废油 再生剂 微观结构 热力学性质 

分 类 号：U414[交通运输工程—道路与铁道工程]