The use of polyethylene terephthalate waste as modifiers for bitumen systems

This study examined the suitability of polyethylene terephtal (PET) waste to provide an alternative modification to bitumen and reduce waste accumulation. The chemical structure and physical properties were evaluated for modified bitumen with different PET flakes content from 2 to 10 %. The effect of PET waste content on bituminous systems was analyzed using IR and 1H NMR spectroscopy, differential thermal (DTA) and thermogravimetric (TGA) analyses. The study of change in the microstructure as a result of bitumen modification was carried out using atomic force microscopy (AFM). Regularities of changes in the structural-group composition of bituminous binders after their modification with PET waste have been established. It is noted that the chemical interaction of the base bitumen with PET flakes occurs due to the formation of associative bonds between the oxygen-containing components of the modifier and bitumen. The influence of the modifier on the physical and mechanical properties was evaluated using standard methods (penetration, extensibility and softening point). Based on the physical and mechanical properties of bitumen, such as needle penetration depth (penetration), ductility and softening point, it was found that the optimal dosage of PET waste in terms of asphalt binder characteristics is 3 %. It has been established that PET waste and original bitumen interact both at the chemical and physical levels and can be considered as a suitable alternative for changing the properties of bituminous binders. Thus, the obtained samples of modified bituminous binders have improved physical and mechanical properties, which makes it possible to produce high-strength asphalt concrete pavements based on them.