Liu Fuming, Qi Aoyun
College of Civil and Architectural Engineering, Nanchang Institute of Technology, Nanchang, Jiangxi, China.
College of Civil Engineering, Chongqing Jiaotong University, Chongqing, China.
PLoS One. 2025 Aug 12;20(8):e0328441. doi: 10.1371/journal.pone.0328441. eCollection 2025.
To understand the blending behavior of virgin and aged asphalt binder in thermally recycled asphalt mixtures, a series of studies on the blending behavior of virgin and aged asphalt based on molecular dynamics simulations have been performed. A blend model was developed for virgin asphalt binder and aged asphalt binder with rejuvenator system, which is saturated with 12 different molecules. In-depth analysis of microscopic blending mechanisms through the effects of rejuvenator content, simulation time, temperature and aged asphalt binder content on the degree of blending of virgin and aged asphalt binder. Using Materials Studio, the blend of virgin and aged asphalt binder under different conditions was quantitatively analyzed. It was found that the degree of blending of virgin and aged asphalt increased gradually with the content of rejuvenator, but the degree of blending decreased slightly when increased to 15%. The degree of blending gradually increased with the increase of time and also with the increase of temperature during the simulation time of 2000 ps. In terms of aged asphalt content, the degree of blending of virgin and aged asphalt gradually decreased with the increase of aged asphalt content. And through the fitting analysis found that the order of correlation between the four factors and the degree of blending was: simulation time > aged asphalt content > temperature > rejuvenator content. To verify the reliability of the results of the molecular dynamics simulation, the performance of recycled asphalt was verified using the asphalt rheological properties test (DSR) and the three major indexes (needle penetration, softening point, and ductility) tests. The results of the combined rheological property test and the three major index tests were found to be consistent with the order of influence of the four factors obtained in the molecular dynamics simulation. Therefore, it can be concluded that the use of molecular dynamics simulation in this study to analyze the blend behavior of virgin and aged asphalt in recycled asphalt is relatively accurate.
为了解热再生沥青混合料中新鲜沥青与老化沥青结合料的混合行为，基于分子动力学模拟开展了一系列关于新鲜沥青与老化沥青混合行为的研究。建立了含再生剂体系的新鲜沥青结合料和老化沥青结合料的混合模型，该体系用12种不同分子进行了饱和处理。通过再生剂含量、模拟时间、温度和老化沥青结合料含量对新鲜沥青与老化沥青结合料混合程度的影响，深入分析微观混合机制。利用Materials Studio对不同条件下新鲜沥青与老化沥青结合料的混合情况进行了定量分析。结果发现，新鲜沥青与老化沥青的混合程度随再生剂含量的增加而逐渐提高，但当再生剂含量增加到15%时，混合程度略有下降。在2000 ps的模拟时间内，混合程度随时间的增加而逐渐提高，也随温度的升高而逐渐提高。就老化沥青含量而言，新鲜沥青与老化沥青的混合程度随老化沥青含量的增加而逐渐降低。通过拟合分析发现，这四个因素与混合程度之间的相关顺序为：模拟时间＞老化沥青含量＞温度＞再生剂含量。为验证分子动力学模拟结果的可靠性，采用沥青流变性能试验（动态剪切流变仪）和三大指标（针入度、软化点和延度）试验对再生沥青的性能进行了验证。流变性能试验和三大指标试验的结果与分子动力学模拟中得到的四个因素的影响顺序一致。因此，可以得出结论，本研究中使用分子动力学模拟分析再生沥青中新鲜沥青与老化沥青的混合行为是相对准确的。
