| Cement emulsified asphalt binder(simplified as CA binder)is a kind of organic-inorganic material composite of cement,asphalt,water and additives through cement hydration and asphalt demulsification.It is nowadays widely used in transportation infrastructure engineering.Aging of CA binder has influence on cement asphalt composite materials mechanical properties such as deformability and fatigue properties,and then influences the application performance of cement asphalt composite materials.Aiming at the problem,the paper studies the effects of aging on deformability and fatigue properties of CA binder,and the characterization of CA binder aging.Firstly,raw materials,mixture ratio,specimen shaping and curing method were determined.Aging test,various mechanical property tests,and asphalt component analysis schemes were determined.Based on theory of viscoelasticity,corresponding constitutive equations of constitutive models to characterize the viscoelastic properties of aged CA binder were established.Secondly,based on creep test and creep recovery test on CA binder,the effects of aging and mix ratio on the creep and creep recover properties of CA binder w ere analyzed.Through fitting analysis of creep and creep recovery test results with the constitutive equations,the best viscoelastic constitutive model to characterize the static mechanical properties of aged CA binder was chosen.Through the analysis of fitting parameters,the effect laws of aging on the static viscoelastic mechanical properties of CA binder were studied.Based on frequency scanning test on CA binder,the effects of aging and mix ratio on the composite modulus and phase angle of CA binder were analyzed.The composite modulus and phase angle principal curves of aged CA binder were obtained by using the time-temperature equivalence principle.The effects of aging on the dynamic mechanical properties and energy dissipation of CA binder were analyzed.Based on fitting analysis of test results with the constitutive equations,the best viscoelastic constitutive model to characterize the dynamic mechanical properties of aged CA binder was chosen.Through the analysis of fitting parameters,and the effect laws of aging on the dynamic viscoelastic mechanical properties of CA binder were analyzed.Thirdly,based on fatigue test on CA binder,the effects of aging and mix ratio on the fatigue life of CA binder were analyzed.The fatigue equation of aged CA binder was established through the fitting analysis of fatigue life,and the effect laws of aging and mix ratio on the fatigue performance of CA binder were analyzed through the analysis of fatigue equation parameters.The evolution laws with fatigue loading of CA binder performance indexes such as composite modulus,phase angle and dissipated energy in the fatigue process under aging were analyzed.Finally,based on theory of damage mechanics,the aging influence factors to characterize the effects of aging on viscoelastic properties and fatigue properties of CA binder were defined and established.And the aging evolution laws of viscoelastic properties and fatigue properties of CA binder were studied.The aging evolution models of CA binder were established by fitting analysis.Through asphalt component analysis of aged CA binder,the aging mechanism of CA binder was preliminary analyzed. |
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