Study On Rheological Properties And Low Temperature Properties Of Asphalt Binders

The high temperature rutting disease,moderate temperature fatigue disease and low temperature cracking disease of asphalt pavement are closely related to the rheological properties and low temperature performance of asphalt binder.Therefore,it is urgent to systematically study the rheological properties and low temperature properties of asphalt binders.The main work and achievements of this paper are as follows:?1?Perform strain scanning tests on five kinds of asphalt?90#matrix asphalt,SBS modified asphalt,SBR modified asphalt,rubber asphalt,cold asphalt?to determine the viscoelastic range of asphalt high temperature line,on the basis of the original and short-term The samples were subjected to temperature scanning test and frequency scanning test under aging conditions,and the high temperature rutting factor was analyzed.The CAM model was used to establish the high temperature main curve of asphalt based on the time-temperature equivalence principle.The results show that the short-term aging of asphalt makes the rutting factor larger and improves the high temperature resistance of asphalt.With the increase of frequency,the main curves of the five asphalts change from dispersion to aggregation,and the short-term aging main curve changes from aggregation to dispersion.?2?Multiple stress creep recovery?MSCR?tests were carried out on five asphalt samples in the original and short-term aging conditions to evaluate the creep recovery ability of asphalt and to classify asphalt traffic grades.The results show that with the increase of temperature and the increase of stress,the non-recoverable creep compliance of asphalt increases.The short-term aging will reduce the non-recoverable creep compliance value of the matrix asphalt and make the non-returnable creep of the modified asphalt.The compliance value increases;the delayed elastic recovery ability of the modified asphalt is better than that of the matrix asphalt.?3?The zero shear viscosity?ZSV?test was carried out on the five asphalt samples in the original and short-term aging conditions to analyze the steady flow characteristics of the asphalt.The results show that the steady shear test is more suitable for determining the viscosity of matrix asphalt and modified asphalt parts than the dynamic frequency sweep test.Both Cross and Carreau rheological models are suitable for fitting the zero shear viscosity of five kinds of asphalt.And the Carreau model fits less than the Cross model.?4?The strain scanning test was carried out on five types of asphalt.The time-scan test was carried out on the basis of determining the viscoelastic range of the mid-temperature line of asphalt,and the effects of different loading strains on the fatigue characteristics of asphalt were studied.The results show that the complex modulus of five kinds of asphalt decreases with time,and the larger the loading strain,the smaller the complex modulus of asphalt,the faster the complex modulus decreases,and the smaller the fatigue life.The fatigue life of cold asphalt is the largest,and the fatigue life of 90#matrix asphalt is the smallest.?5?Using the bending beam rheology test?BBR?to test the low temperature rheological properties of five kinds of asphalt samples under the conditions of original,short-term aging and long-term aging,and using the Burgers viscoelastic model to fit the low temperature creep compliance curve.And build a low temperature viscoelasticity evaluation index of asphalt.At the same time,using the power function model,the main curve of low temperature creep of asphalt is established based on the principle of temperature and temperature equivalence.The results show that the Burgers model can accurately describe the low temperature creep behavior of five kinds of asphalt,and the instantaneous elastic parameter?E₁?and the delayed elastic parameter?E₂?of the Burgers model will have intersections with the decrease of temperature.The temperature range of the intersection is-18°C to-24°C,as the asphalt aging degree deepens,the intersection position will move;the power function model can accurately describe the five asphalt low temperature creep master curves.?6?The glass transition temperature of five kinds of asphalt was determined by differential scanning calorimetry?DSC?,and the correlation between low temperature elastic index of asphalt and other low temperature indicators was analyzed based on grey correlation theory.The results show that with the decrease of temperature,the correlation between dissipative energy ratio,relaxation time and low temperature comprehensive compliance parameter and asphalt glass transition temperature is decreasing,and the correlation with asphalt glass transition temperature is increasing.Creep rate,brittle point,glass transition temperature and dissipative energy ratio can better evaluate the low temperature performance of asphalt.