Effect Of SARA Fractions Content On Rheological Properties Of Asphalt Binder

As the basic chemical composition of asphalt,SARA fractions have great effect on the rheological properties of asphalt binder.Nowdays,most prevalent research is focus on the effect of types,aging and modification on rheological properties of asphalt,few researchers focous on the effect of SARA fractions on rheological properties of asphalt.Meanwhile,most researchers study the rheological properties of asphalt based on the dynamic shear rheometer which can only test the macro rheological properties of asphalt binder.The shortage of this equipment is that it can not test the microrheological properties of materials.Thus,study the effect of SARA fractions on rheological properties and explore a new method to test microrheological properties of asphalt is meaningful to understand the properties of asphalt binder and improve its service performance.This paper studied the effect of SARA fractions on the macro and micro rheological properties of asphalt binder.Firstly,the pure SARA fractions were separated based on the four-component separation method and mixed into the original asphalt with designed proportion to obtain derived binders.The macro rheological properties were studied by testing the original neat asphalt binder and their derived binders.The viscoelasiticity of asphalt under dynamic and static loads was studie by the dynamic shear rheometer.The effect of SARA fractions on the dynamic modulus,phase angle,creep compliance and relaxation modulus were analyzed.To enrich the test methods on the rheological properties of asphalt binder and cover the shorage of study on micro rheological properties.The micro-morthology and basic mechanism of asphalt were tested by atomic force microscope.The effect of SARA fractions on micro-morphology and chemical composition corresponding to the micro-morphology were analyzed.The effect of SARA fractions on the adhesion,DMT modulus and dissipation energy were also studied.Using the micro rheology study method from life science field for reference.A commom used model was chosen to fitting micro rheological parameter curves.Finally,the result of micro rheological test was compared with result of macro rheological test and the differences of them were analyzed.In this paper,the effect of SARA fractions on the macro and micro viscoelastic properties of asphalt is expounded,and the testing methods of micro viscoelastic properties of asphalt are preliminarily explored.This paper lays a foundation for further understanding the effect of chemical compositions of asphalt on its macro properties and the measurement of micro rheological properties of asphalt materials.