Preparation And Mechanism Analysis Of Graphene Oxide/Asphalt Composites

Asphalt material is one of the main infrastructure materials and has a wide range of applications in the field of engineering construction.But for a long time,the basic research and development of asphalt materials is still weak,the existing technical methods cannot get further research on the microstructure of asphalt materials.This paper combines the development trend and the technical research status of asphalt materials,used graphene oxide as an asphalt admixture and prepared graphene oxide/asphalt composites by high temperature melting method,studied the effect of graphene oxide on the asphalt physical properties and analyzed the microstructure of composites by XRD,SEM and FTIR.In order to reveal the composite mechanism,we constructed the molecular simulation models of the asphalt composite material and did a molecular dynamics study to illustrate the microstructure changes in composites,through the first-principles calculation to clarify the surface interface between graphene oxide and asphalt.The specific findings are as follows:As the content of graphene oxide increases,the softening point of asphalt is increase,the penetration and ductility are decrease,when the graphene oxide content reaches 0.5%,the change of asphalt performance has slowed down,the optimum content of graphene oxide is 0.5%?0.7%,and the optimum shearing time and optimum shear rate during the preparation of the composite are 60min and 6000r/min,respectively.Research on the microstructure of the material found that the spacing of the graphene oxide sheet became large,graphene oxide can be uniformly dispersed in the asphalt and without significant influence on the asphalt functional group,the experimental results show that there may be only a physical interaction between graphene oxide and asphalt.The results of molecular dynamics show that the asphalt exhibits a sol structure in the temperature range of-155??85?,when the temperature is greater than 127?,the asphalt sol structure is destroyed.When the graphene oxide is added to the asphalt and the temperature is less than 25?,the resin molecules are converted from adsorbed around the asphaltene to adsorbed around the graphene oxide.When the temperature reaches 205?,the resin molecules are detached from the graphene oxide and graphene oxide becomes combined with asphaltene molecules.The results of first-principles calculations show that the combination of asphalt resin component and graphene oxide is the most stable,followed by asphalt aromatic component and graphene oxide,the combination of asphalt saturate component and graphene oxide is the weakest.Graphene oxide can form hydrogen bonds with asphalt molecules,and it also can form aromatic ring stacking with asphalt aromatic molecules or resin molecules,the aromatic ring stacking of resin molecules is stronger.Graphene oxide can hinder the movement of saturate molecules and improve the high temperature stability of asphalt,it can also inhibit the volatilization of saturate molecules and improve the heat aging resistance of asphalt.Through molecular simulation,we found there is only a physical interaction between graphene oxide and asphalt,the hydrogen bonding and the aromatic ring stacking in the composite material is the main reason why the graphene oxide can be stably dispersed in asphalt.