Constitutive Equations Of Epoxy Asphalt Binders

Epoxy asphalt binders(EABs)have been widely used in road and steel bridge pavement in recent years.In comparison to conventional thermoplastic asphalt binders,EABs'thermosetting or quasi-thermosetting properties can reduce their thermal susceptibility significantly,which can improve their service life as a pavement material.However,their constitutive equations are not clear.In this dissertation,anhydride-(AN-EABs)and amine-cured(AM-EABs)rubber-like epoxy asphalt binders were used and their constitutive models were studied.All experiments in this dissertation were conducted by dynamic shear rheometer.First,creep tests and stress relaxation tests of AM-EABs were implemented.Next,amplitude sweeps of AN-EABs and AM-EABs in different asphalt contents were conducted,through which we can confirm the linear viscoelastic(LVE)region of binders.Subsequently,temperature sweeps and frequency sweeps were carried out.Based on these measurements,time-temperature superposition principle(TTSP)was used to shift these master curves(G*vs.?)to from a continuous and smooth master curve.And then,fractional linear solid(FLS)model,Huet-Sayegh(HS)model and 2S2P1D model were used to fit these superposed master curves and describe the viscoelasticity of EABs with different asphalt contents in LVE.Eventually,we drew the curves about horizontal shift factor?_T vs.temperature,Arrhenius equation,WLF equation and arctangent function were used to fit them,respectively.Through the research,we have achieved three conclusions:1.Modified fractional Burgers model with four elements can describe the creep curve well,and we also proposed a new model called“double-real order model”,it can describe the relaxation modulus of binder at all load time very well.2.Whether for AN-EABs or AM-EABs,HS model and 2S2P1D model can approach good results in describing the master curves(G*vs.?)of EABs,and we can study binders'rheological properties by analyzing their fitting parameters.With the increase of asphalt content,2S2P1D model degraded into HS model.Therefore,HS model was regarded as an ideal for thermosetting EABs.3.Arctangent function can fit the temperature dependence of horizontal shift factor?_T across the glass transition temperature.Therefore,combined this function and HS model,we can calculate the parameters of EABs at any temperatures and frequencies;it is of great significance to predict the service performance for epoxy asphalt pavement.