从微观角度分析沥青老化后与集料界面粘附愈合行为,采用Materials Studio 2020软件,分别构建老化沥青、集料、老化沥青-集料界面粘附愈合模型,从密度、玻璃化转变温度和溶解度参数验证构建模型的准确性.基于分子动力学模拟,分析再生剂类型和温度变化对老化沥青-集料粘附愈合模型的界面相对浓度、粘附能的影响.结果表明:构建的老化沥青模型参数合理,能够表征真实老化沥青特性;随着温度的升高,界面相对浓度先升高后降低,温度为298 K时达到最大;界面相对浓度由大到小对应的再生剂类型依次为R2＞R1＞R4＞R3,链状、小分子量再生剂对界面相对浓度提升幅度最大;温度和再生剂通过改变沥青与集料界面的粘附能,影响模型愈合速率,范德华势能是影响界面模型粘附能的主要因素.
Adhesion healing behaviour of aged asphalt-aggregate interface based on molecular dynamics simulation
To conduct a comprehensive analysis of the attachment and repair behavior of the interface between aged asphalt and aggregate from a microscopic perspective,this paper builds a detailed attachment and repair model.It encompasses the aging asphalt,the aggregate material,and the crucial interface that binds them together.To facilitate the modeling process,Materials Studio 2020 software,specifically designed for molecular simulations and materials modeling,is employed.The accuracy and reliability of the constructed model are meticulously verified through various parameters,including density,glass transition temperature,and solubility.These parameters are essential in characterizing materials at the microscopic level,ensuring the model effectively represents real-world aging asphalt properties.The model's robustness is essential for further exploration of how different variables,such as temperature changes and the type of rejuvenating agents,influence the interfacial interactions and overall performance of the asphalt-aggregate system.The investigation is primarily based on molecular dynamics simulations,which allow for the detailed exploration of the behaviors of molecules within the system under various conditions.An important focus of our study is to analyze how the type of reclaimer used,alongside variations in temperature,impact the relative concentration at the interface as well as the adhesion energy.The interactions at the interface are critical for the overall performance of asphalt in practical applications,such as road construction and maintenance,where the durability and longevity of the material depend heavily on these factors.Our results obtained from the simulations indicate the parameters used to build the aging asphalt model are sensible and aligned well with established properties of aged asphalt.Specifically,as the temperature increases,the interfacial relative concentration exhibits a characteristic trend:it increases to a certain point and then decreases.This behavior is particularly noticeable at a temperature of 298 K,where the interfacial relative concentration reaches its peak value.Our finding has significant implications,suggesting an optimal temperature range for achieving maximum adhesion efficiency between the asphalt and aggregate.Moreover,it reveals different types of rejuvenating agents significantly affect the interfacial relative concentration,displaying a clear hierarchy:R2 exhibits the highest effectiveness,followed by R1,R4,and finally R3.Among these,chain-like small molecule rejuvenating agents are particularly influential in increasing the interfacial relative concentration,which highlights the importance of agent selection when aiming to enhance the adhesion properties of aged asphalt.In addition,both temperature and the nature of the rejuvenating agent are found to markedly influence the adhesion energy at the asphalt-aggregate interface.By altering these two factors,the adhesion energy,which is paramount for the longevity and effectiveness of the material interface,is also altered.Specifically,the adhesion energy between the asphalt and aggregate is shown to directly affect the repair rate of the model,which is crucial for practical applications where repair and maintenance are required over time.Van der Waals potential energy emerges as a key factor influencing the adhesion energy within the interface model,emphasizing the role of intermolecular forces in determining the overall stability and durability of the asphalt-aggregate interface.Collectively,these findings provide a valuable theoretical framework and experimental basis for understanding the complex interactions at play between aged asphalt and aggregate,which is pivotal for developing strategies to improve the adhesion properties,thereby enhancing the performance and lifespan of asphalt materials used in construction and infrastructure.The implications of our research extend beyond academic field,offering practical solutions for real-world challenges in material engineering and maintenance.
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