Study On Durability Of Graphene Modified Asphalt

In this paper,the long-term durability of modified asphalt is analyzed in the background of modified asphalt.It is mainly pointed out that in nano-modified asphalt,the research of graphene modified asphalt is at an early stage,mostly staying in the study of high and low temperature performance of asphalt,while the research on durability of asphalt is relatively scarce.In order to obtain graphene modified asphalt with better performance,starting from the characteristics of graphene obtained by different graphene preparation methods,graphene(A)prepared by redox method and graphene(B,C)prepared by mechanical peeling method were used.Type B was ordinary graphene prepared by mechanical peeling,and type C was surface modified on the basis of type B.Based on the principle of melt blending,graphene modified asphalt was prepared by highspeed shearing machine.The compatibility of three types of graphene with base asphalt was analyzed.It was concluded that the compatibility between graphene prepared by mechanical peeling and base asphalt was the best,and the stability of graphene modified by surface was the best.Finally,C-type graphene was selected to prepare graphene modified asphalt.Scanning electron microscopy(SEM)was used to observe the micromorphology of three types of graphene,and the compatibility of matrix asphalt was analyzed from the micro-structure of graphene lamellae.The high and low temperature properties of six kinds of graphene modified asphalts with different content were studied.It was concluded that the addition of graphene would improve the high temperature performance of matrix asphalt,but would damage the low temperature performance.The optimum content of graphene was 0.35% through comprehensive analysis of the high and low temperature performance test results.Taking graphene asphalt with the optimum content as the research object of durability,the performance changes of matrix asphalt and graphene modified asphalt after short-term aging and long-term aging were compared respectively,and it was concluded that the thermal and oxygen aging resistance of graphene modified asphalt was significantly improved for matrix asphalt.The aging resistance mechanism of graphene modified asphalt was explained.Fourier transform infrared spectroscopy was used to analyze the aging mechanism of asphalt.Quantitative analysis showed that the rate of change of carbonyl functional group index and sulfoxide functional group index W of graphene modified asphalt in two aging stages was lower than that of matrix asphalt.It indicated that graphene could inhibit the oxygen entry of asphalt and improve the anti-oxidative aging ability of asphalt.The fatigue properties of matrix asphalt mortar and graphene modified asphalt mortar were studied by means of stress control model under DSR time scanning test.The results show that the fatigue life of graphene modified asphalt mortar is obviously higher than that of matrix asphalt mortar,and the influence of filler-asphalt ratio(0.8-1.2)on the fatigue life of asphalt was studied.At present,the fatigue life increases correspondingly with the increase of filler-asphalt ratio.The fatigue resistance mechanism of graphene modified asphalt mortar was explained.