The Research On Evaluation Index Of High Temperature Performance Of Asphalt Binder

High temperature flow of asphalt pavement deformation has been widespread concern around the world the main form of the early damage of pavement,which is mainly due to lack of ability to resist high temperature deformation of asphalt pavement,and asphalt rheological properties of material on pavement high temperature performance plays an important role,therefore,many researchers began to focus on study on high temperature properties of asphalt mixture,and the applicability of the binder evaluation index for high temperature performance assessment.Many countries at home and abroad have been trying to find the technical indicators that can truly show the performance of asphalt pavement,in order to reduce the early damage phenomenon of asphalt pavement.So far,a lot of road researchers at home and abroad have devoted themselves to this,and put forward many new indicators,but the correlation between each index is very poor,and the scope of application is also different.This paper selects 6 representative asphalt,including 3 kinds of asphalt and 3 kinds of modified asphalt,the asphalt binder used in the domestic and foreign high temperature performance appraisal index as the foundation,especially in the United States,Europe's new index can not recover the creep compliance of Jnr and zero shear viscosity(ZSV)the high temperature performance evaluation results,analysis of different types of asphalt and asphalt mixture rutting test data verified,analyzed,the main conclusions are as follows:(1)Comparing the actual measured softening point before and after aging of each asphalt with the measured softening point and equivalent softening point of each asphalt,it is found that only the modified asphalt will have an aging softening point less than the softening point before aging and the actual softening point of the modified asphalt The difference between the point and the equivalent softening point is huge.This phenomenon may be due to the larger amount of modifier in the modified asphaltene and the formation of the network structure,though the asphalt softens.However,the network structure formed by the modifier can still Prevent the ball from falling.(2)Through the change of dynamic viscosity and rutting factor before and after aging,it can be found that the growth rate of matrix asphalt should be greater than that of modified asphalt.It can be considered that due to the high viscosity of modified asphalt,at high temperature of 163? in RTFOT aging test Under conditions difficult to flow uniform formation of asphalt film,which aging is not sufficient.Considering that the mixing temperature of modified asphalt is also higher than the mixing temperature of matrix asphalt,it is recommended to simulate the short-term aging in modified asphalt mixing process by RTFOT method,and the temperature of the oven should be appropriately increased.(3)There is a good correlation between zero shear viscosity and non-recoverable creep compliance and the dynamic stability of rutting test.It is recommended to introduce these two indexes and the corresponding test methods in the evaluation of asphalt high temperature performance in our country.