Spreading And Wetting Behavior Of The Rejuvenator On The Surface Of Aged Asphalt And Its Effect On The Performance Of The Mixture

The maintenance of highway in our country generates a huge amount of RAP material every year,which will lead to a series of social and economic problems if improperly disposed.The blending ratio of the RAP material is low,and the unsatisfied effect after regeneration constrains the development of the plant mix hot recycling technology.The key problem affecting the thermal regeneration of RAP material is that the wetting and diffusing mechanism of the rejuvenator on the surface of RAP material is not well understood.Study on the wetting and diffusing mechanism of rejuvenator on the surface of RAP material is of great practical significance to China's construction of resource-saving and environment-friendly country.In view of the above problems,the paper mainly studied from the following aspects:Firstly,by using the sessile drop method,I confirmed the contact angle of the titration liquid on the surface of asphalt,then I calculated the dispersion component and polarity component of asphalt surface free energy according to the Owens-Wendt theory,by which the surface free energy of asphalt is obtained.Then the aged asphalt was prepared by indoor simulated aging method,and the relationship between the asphalt's aging and its surface property was studied systematically.Secondly,from the angle of the driving force and speed,the spreading and wetting effect of the rejuvenator on the aged asphalt surface was studied.Then the type of asphalt,the aging degree of asphalt,the relationship between the type of rejuvenator and the spreading coefficient,as well as the relationship between the type of rejuvenator and the wetting speed index was researched.Furthermore the spreading and wetting effect of the rejuvenator was evaluated.Based on the Marshall mixture design method,I designed the proportioning of the hot recycled asphalt mixture.In this paper,the gradation type of recycled mixture and the best dosage of rejuvenator were calculated by laboratory test.On this basis,the proportion of recycled asphalt mixture was designed,specifically,the reasonable gradation type of hot recycled asphalt mixture added with different aged materials and the best asphalt ratio were designed.By systematically comparing the effect of rejuvenator on the road performance of reclaimed asphalt mixture,the regular pattern of improvement of the rejuvenator on the waste asphalt mixture's road performance was obtained.The result shows that the rejuvenator with large surface tension and low viscosity can improve the road performance of the waste asphalt mixture effectively.