Molecular simulations and experimental evaluation on the curing of epoxy bitumen

To more fundamentally understand the curing process of the epoxy modified bitumen (EMB), this study used the molecular dynamics simulation and the first principles to investigate the molecular movement and the structural change during the curing. The Fourier transform infrared spectroscopy, fluoroscopes microscopy and dynamic shear rheometer were used to characterize the chemical, structural and rheological properties. The simulation and experimental results indicated that: the diffusion speeds decreased in order of aromatics, saturates, epoxy and asphaltenes in the EMB at a typical curing temperature of 120 A degrees C; during the curing process, epoxy can easily move to aromatics and saturates; according to first principle, the covalent binding between epoxy and bitumen formed during the curing process, and calculated bond-length was very close to the experimental value; the curing efficiency decreased with the increase of the epoxy resin content; a clear network structure at a high content of 20 wt% epoxy resin can be clearly observed; the epoxy modification can improve the high-temperature deformation resistance.