Diffusion characteristics of asphalt rejuvenators based on molecular dynamics simulation

ABSTRACT

In recent years, the regeneration technology of aged asphalt in construction engineering has received much attention. The diffusion performance of the rejuvenator is a key factor in this kind of regeneration technology. But at present, the relevant research is still not mature. To forward this research, this study established molecular dynamic models of three diffusion systems with the open source large-scale atomic/molecular massively parallel simulator, including new asphalt, short-term aged asphalt and long-term aged asphalt. This study then analysed the diffusion mechanism and influence factors including temperature, ageing and the diffusion laws of different kinds of molecules. It was found that besides thermal motion, molecular force also greatly contributes to the diffusion of asphalt and rejuvenator. It was also found that micro voids in asphalt increase the contact area and promote the fusion of the rejuvenator and asphalt. Diffusion speed increases as temperature rises, and diffusion speed in aged asphalt is higher than that in new asphalt, especially at higher temperatures. The simulation results also suggest that small or catenarian molecules diffuse faster than the network structures.

KEYWORDS:

• Diffusion
• rejuvenator
• asphalt
• molecular dynamics simulation
• ageing

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51408154]; The China Postdoctoral Science Foundation [grant number 2013M541393]; [grant number 2015T80357]; The Heilongjiang Postdoctoral Science Foundation [grant number LBH-Z13084]; The Open Fund of Key Laboratory of Road Structure and Material of the Ministry of Transport [grant number kfj140304] (Changsha University of Science & Technology); The Fundamental Research Funds for the Central Universities [grant number HIT. NSRIF. 2017043] and Liaoning Transport Research Project [grant number 201604].