Taiuyan, China – The asphalt used in road surfaces gradually degrades over time, and chemical modifications can be used to improve its ageing properties. Scientists at the North University of China have used both experimental techniques and molecular dynamics simulations to look at the ageing resistance of both thermoplastic polyurethane-modified asphalt and polyurethane/graphene oxide composite modified asphalt.
The aim was to investigate both the molecular composition and self-healing ability of aged asphalt, with base asphalt and virgin asphalt used as a control. Ageing experiments were carried out using a rolling thin-film oven test, with analysis via multiple techniques including DSC, TGA and FT-IR studies. They also simulated the molecules and crack models of asphalt via molecular dynamics experiments.
Their experiments showed that PU and graphene oxide modifications can increase the melting temperature of the asphalt, and improve the asphalt molecules’ migration ability. Importantly, it also enhanced the self-healing diffusion properties of the asphalt molecules, and reduced the energy and viscosity of aged asphalt. They concluded that nano and chemical synergistic modification does indeed have a positive effect on the properties of the asphalt as it ages.
The work has been published in the journal Molecular Simulation.
