Research On Preparation Technology And Properties Of Polyurethane Modified Petroleum Asphalt

In recent years,the related to density and mileage of highways in China have been boosted remarkably with a promising development,which’s performance has to dependent on quality of petroleum asphalt.Polyurethane(PU)is a kind of organic polymer material with excellent performance.It is of great theoretical significance and practical value to conduct a comprehensive and systematic study on its use as asphalt modifier.Firstly,the research is conducted from the perspective of exploring the advantages by comparing the direct modification method and the prepolymer modification method.The results show that the high temperature stability and low temperature cracking resistance of the modified asphalt are improved after the polyurethane is directly added to the asphalt for modification,but the segregation phenomenon is obvious,which is not conducive to the modified asphalt.The results show that the performance of asphalt is further enhanced,and the segregation phenomenon is conquered.Therefore,the prepolymer modification method was used for subsequent process research.Then,the preparation process conditions were explored to obtain the best preparation process: PU and asphalt with a content of 5% were mixed and stirred at a temperature of 130 ℃ using a dispersing disc,and the stirring rate was set to 1000 r/min for continuous stirring.After stirring for 40 minutes,it was transferred to an oven at 110 ℃ for 6 hours.Secondly,in order to further analyze the degree of correlation between each process condition and the performance of polyurethane modified asphalt,the grey correlation analysis method was adopted in this paper to obtain three factors with good correlation degree,namely stirring temperature,growth temperature and PU content,as well as the process condition with the highest comprehensive evaluation,and combined with the experimental data to establish a threedimensional function prediction model that can express the performance of modified asphalt to further verify the preparation process conditions.Through the comparison of experimental verification and analysis data,the results prove the rationality of the preparation process and functional simulation,which is in line with the asphalt industry standard.Finally,by means of characterization methods such as family composition,infrared spectroscopy,and thermogravimetric analysis,the structural changes before and after the polyurethane modified asphalt were discussed,as well as the modification mechanism and the reasons for the influence of the preparation process on the macroscopic technology were also discussed.The properties of modified asphalt are further elaborated.The results of family component analysis show that the light components of the modified asphalt have little change,the content of asphaltene components increases,and the modification process is mainly the mutual transformation between the heavy components,and content of the components is closely related.The active groups in the asphalt react to generate new functional groups;thermogravimetric analysis shows that the polyurethane modified asphalt contains more high temperature resistant substances.To sum up,polyurethane-modified asphalt will affect the mass fraction of asphaltenes,thereby changing the macroscopic road performance of asphalt.