Preparation and properties of bitumen modified by EVA graft copolymer

This paper presents a laboratory study of modified bitumen containing ethylene vinyl acetate (EVA) and ethylene vinyl acetate grafted maleic anhydride (EVA-g-MAH) copolymers. When the different polymers were added, the physical properties of modified bitumens, such as softening point, ductility at low temperature and storage stability at high temperature are changed. The polymer modified bitumens (PMBs) were analyzed by thermogravimetry (TG), derivative thermogravimetry (DTG) and fourier transform infrared spectroscopy (FTIR). Thermal characterizations showed that the main decomposition stage refers to samples with modifiers exhibited a slight increase in thermal stability and the sample with the highest stability was EVA-g-MAH PMBs. FTIR analysis suggested that it is difficult to prove the EVA-g-MAH has reacted with the functional group in bitumen by FTIR spectrum. The dynamic shear rheometer (DSR) tests reported that added content of EVA-g-MAH has great effect on the rheological properties of the binder and its high temperature performance was improved while its temperature susceptibility was reduced in compare to EVA modified bitumens binder.

Research highlights
► This paper presents a laboratory study of modified bitumen containing ethylene vinyl acetate (EVA) and ethylene vinyl acetate grafted maleic anhydride (EVA-g-MAH) copolymers.
► When the different polymers were added, the physical properties of modified bitumens, such as softening point, ductility at low temperature and storage stability at high temperature are changed.
► EVA-g-MAH modified bitumen mixture has higher thermal stability than EVA PMBs.
► The rheological properties of PMB samples are improved.