Research On The Key Properties Of Binder For Asphalt Plug Joints

At present,Asphalt plug joints（APJs）have been widely used in small and medium-sized bridges with small expansion amout.The performance of the binder used in APJs has a great influence on the overall performance of APJs,but the current research on APJs binders is insufficient,not only la cks a systematic and comprehensive evaluation of APJs binder performance,but also lacks corresponding evaluation systems and evaluation indicators.Therefore,this paper has carried out the following the study:In view of the lack of performance testing methods for APJs binders,the dynamic shear rheometer（DSR）and the bending beam rheometer（BBR）are used for a typical APJs binder（MUT）.And according to the SHRP plan,the high temperature and low temperature rheological properties of MUT materials were evaluated by corresponding indicators.The results show that the above methods are effective in testing the high temperature and low temperature properties of MUT materials.MUT material has strong high temperature and low temperature performance.The complex modulus curves of MUT materials at different frequencies and temperatures are obtained through frequency sweep experiments.The master curve is drawn based on the principle of time-temperature equivalence,and the master curve data is fitted with the Sigmoidal model,GLS model and CAM model.The results show that the three models have good results in fitting the master curve of complex modulus of MUT materials,but they all have certain limitations.In addition,the expression of the glass transition te mperature is further derived by using WLF,and the glass transition temperature of the MUT material is fitted,which indicates that the low temperature crack resistance of the MUT material is better.After investigating the APJs on-site construction process,based on the research results and the factors affecting the short-term aging of asphalt,the laboratory short-term aging simulation method and operation process for APJs binfers are determined.The MSCR test was conducted to test MUT materials under dif ferent aging conditions.The results showed that the increase of aging time and aging temperature and the participation of oxygen would aggravate the aging degree of MUT materials.The enhancement of high temperature performance by short-term aging mainly occurred in the aging process.120min before.When the MSCR test is used to study the high-temperature performance of APJs binders,it is reasonable to widen the temperature appropriately,and the evaluation effect of J _nr 3.2 and R3.2 is better.The FTIR test is used to analyze the changes of the MUT functional group index after different aging times,Among them,the sulfoxide index and butadiene index are relatively abnormal,which is not suitable for measuring the aging degree of MUT materials.The linear rheological range of the MUT material is studied through the stress sweep test and the strain sweep test.The test results show that the increase of temperature will reduce the linear rheological range of the MUT material,and the influence of frequency has no obvious law.Based on different types of modulus will affect the determination of the linear rheological range of MUT materials.The selection of the initial modulus and the reduction ratio will directly affect the determination of the linear rheological range.The viscoelasticity of the material was further studied by creep tests,and the results showed that short-term aging can significantly expand the linear viscoelastic stress range of MUT materials.The power exponential polymer model adopted has achieved ideal results,but it is difficult to pass directly Fitting parameters judge the influence of different test conditions on MUT materials,and cannot effectively distinguish between linear viscoelastic range and nonlinear viscoelasticity.