Investigation Of Rheological And Microscopic Properties Of Devulcanized And Pyrolytic Crumb Rubber Modified Asphalt

The rapidly growing scrap rubber tires have caused serious,"black pollution" to the environment.Crumb rubber modified asphalt technology can not only consume scrap rubber tires but also improve the performance of pavement.However,conventional crumb rubber modified asphalt(CRMA)has some defects such as high viscosity,easy to separate and so on.Devulcanized and pyrolytic crumb rubber modified asphalt(DCRMA)solves the problems of high viscosity and easy segregation of the system,but the longtime high-speed shear at high temperature not only increases the cost of preparation and limits its efficiency,but also leads to the aging of crumb rubber and base asphalt.In view of the shortcomings of the preparation process of crumb rubber modified asphalt and most devulcanized and pyrolytic crumb rubber modified asphalt at present,a new method of preparing devulcanized and pyrolytic crumb rubber modified has been proposed in this paper.Then the preparation parameters were completed,and the basic properties,rheological properties,aging properties and micro-properties of DCRMA were studied.The main results are as follows:(1)The determination of preparation process parameters.The preparation process parameters were determined by using penetration,softening point and rotating viscosity as performance control indexes.It was found that if penetration as the main control index,the solubility of rubber powder and the aging of matrix asphalt can be well balanced.Finally,the development time and shearing time corresponding to the maximum penetration are taken as the time parameters of the preparation process.(2)Investigation of conventional properties.The conventional properties of DCRMA and CRMA were studied by solubility test,elastic recovery test and low temperature ductility test,(3)Investigation of Rheological properties.The high and low temperature rheological properties of CRMA and DCRMA were evaluated by DSR and BBR tests based on rheology,and the validity of the TTSP of crumb rubber modified asphalt was discussed by using Black curves.Finally,the PG classification of four kinds of asphalt modified by rubber powder was determined.(4)Evaluation of aging properties.The short-term aging and long-term aging samples of CRMA and DCRMA were prepared by RTFOT test and PAV test,respectively.MSCR test and final fatigue temperature test were carried out on the samples after short-term aging and long-term aging.The aging properties of CRMA and DCRMA were evaluated.(5)Evaluation of microcosmic characteristics.The modification mechanism and dispersion morphology of rubber powder in CRMA and DCRMA were analyzed and studied by FTIR test and fluorescence scanning test.