| Epoxy asphalt is a kind of special polymer modified asphalt,which is combined of matrix asphalt and epoxy resin and curing agent.Because of curing reaction during production,they generate thermosetting elastomers,which changes the thermoplastic of general asphalt fundamentally.Epoxy asphalt has the advantages of high strength and strong resistance to deformation and good interlaminar bonding capacity and temperature stability,so it is widely used in large-span steel bridge deck pavement and high special road of anti-rutting performance.Epoxy asphalt was first used in the Second Nanjing Yangtze River Bridge and has showed good road performance.And since then epoxy asphalt has been widely used in the domestic longspan bridge deck pavement.However,since the epoxy asphalt is very brittle and hard after curing,especially in low temperature conditions,it is very easy to cause fatigue damage for large span steel bridge deck.Therefore it is of great importance to give epoxy asphalt a certain degree of flexibility and toughness.The properties of epoxy asphalt are related to the compatibility of epoxy resin and asphalt.As the matrix asphalt is a weakly polar or non-polar material,and the polarity of epoxy resin is very strong,the polarity between the two is quite difference,according to the similar principle of compatibility,the compatibility between epoxy resin and asphalt is very bad.In this paper,the thermal stability of epoxy resin and asphalt is characterized by the method of softening point differences and viscosity ratio,and then the compatibility between epoxy resin and asphalt is evaluated.In order to improve the compatibility of epoxy resin and asphalt,the effects are investigated by grafting modified asphalt and adding the third component.The results show that both methods can improve the compatibility of the system.Moreover microscopic analysis by fluorescence microscopy shows that both methods improve the uniformity of the dispersion of epoxy resin,and the effect of grafting modified asphalt on improving the compatibility of the system is better than adding the third component.In this paper,the influence of compatibility on the flexibility and toughness of epoxy asphalt is investigated.The results show that improving the compatibility of epoxy asphalt system has different effects on its flexibility under the different amount of epoxy resin.When the amount of epoxy resin(10wt%~30wt%)is small,the compatibility problem has little influence on epoxy asphalt's flexibility,so improving the compatibility of the system can not improve its flexibility effectively.However,when the amount of epoxy resin(30wt%~50wt%)is large,increasing the compatibility of the system can improve the flexibility of epoxy asphalt significantly.At the same time,the compatibility problem has a great influence on the toughness of epoxy asphalt,and its toughness can be improved greatly with better compatibility.In order to further improve the flexibility and toughness of epoxy asphalt and to exert its excellent road performance,the influence of commonly used polymer waste powder and SBR on the flexibility and toughness of epoxy asphalt is also investigated.The results show that SBR modified epoxy asphalt has little effect on the low temperature modulus of epoxy asphalt,and it can not reduce the low temperature modulus of epoxy asphalt and improve its flexibility effectively.At the same time,SBR modified epoxy asphalt does not improve the toughness of epoxy asphalt,but to a certain extent,reduce the toughness of epoxy asphalt,which is mainly related to the nature of raw materials and epoxy asphalt's special thermosetting.For the rubber powder modified epoxy asphalt,the epoxy asphalt under different curing system performs slightly different.The rubber powder does not improve the toughness of epoxy asphalt under different curing system,but for the aromatic ring acid anhydride curing agent system,rubber powder to a certain extent,can improve the low temperature flexibility of epoxy asphalt. |
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