Development And Properties Of High Viscosity Modified Asphalt Combined With Coal Direct Liquefaction Residue

China is rich in coal but poor in oil and gas,and its energy structure has always been dominated by coal.In order to adjust the energy structure,the technology of "coal-to-oil" has been gradually developed,and the direct coal liquefaction technology has been applied in the coal-to-oil industry on a large scale due to its unique advantages,resulting in a high annual output of direct coal liquefaction residue(DCLR).At present,DCLR is mostly used as fuel in the form of solid waste,which causes a waste of resources to some extent.Some studies have found that DCLR is similar to lake asphalt in composition and can be used as asphalt modifier.Based on the above reasons,this thesis develops DCLR high viscosity modified asphalt with DCLR as the main modifier and SBS and rubber powder as the modifier,and systematically studies its rheological properties and road performance in order to realize the high-value utilization of DCLR.The main research contents of this thesis are as follows:1.The properties of DCLR high-viscosity modified asphalt were studied,and the high-temperature performance,low-temperature performance,temperature sensitivity and fatigue resistance of DCLR high-viscosity asphalt were analyzed through rheological tests(DSR and BBR)of asphalt binder.Determine the PG grade of DCLR high viscosity asphalt and its applicable area;The microscopic state of DCLR high viscosity asphalt was analyzed by fluorescence microscope.The road performance of DCLR high-viscosity asphalt mixture is evaluated by mixture verification tests(high-temperature rutting,low-temperature beam and immersion Marshall),and compared with LT high-viscosity modified asphalt commonly used in the market,and the technical advantages of this material are analyzed.2.The properties of DCLR high-viscosity modified asphalt were studied,and the high-temperature performance,low-temperature performance,temperature sensitivity and fatigue resistance of DCLR high-viscosity asphalt were analyzed through rheological tests(DSR and BBR)of asphalt binder.The microscopic state of DCLR high viscosity asphalt was analyzed by fluorescence microscope.The road performance of DCLR high-viscosity asphalt mixture is evaluated by mixture verification tests(high temperature rutting,low temperature beam and immersion Marshall),and compared with the performance of high-viscosity modified asphalt commonly used in the market,and the technical advantages of this material are analyzed.The main conclusions of this thesis are as follows:1.By analyzing the results of three indexes test and dynamic viscosity test of each compound material mixed into asphalt,it is determined that the best proportion of high viscosity modified asphalt is 6%SBS+5%DCLR+3%DBP+10% rubber powder +4%aromatic oil +0.15% stabilizer.The DCLR high-viscosity asphalt was evaluated by three indexes test,dynamic viscosity test and short-term aging test.The results showed that the conventional performance of the prepared high-viscosity asphalt met the relevant technical indexes,and its aging resistance was outstanding.2.By analyzing and comparing the cost of main raw materials of DCLR high viscosity asphalt,it is found that it has great economic and social value.Considering the factors of temperature and traffic volume,DCLR high-viscosity asphalt is suitable for hot summer areas and areas with high heavy vehicles.3.The comprehensive analysis of DSR test and BBR test shows that the high-temperature performance of DCLR high-viscosity modified asphalt is better than LT high-viscosity asphalt,and the low-temperature performance of LT high-viscosity asphalt is better than DCLR high-viscosity asphalt.DCLR high viscosity asphalt has good fatigue resistance.The temperature sensitivity of DCLR high viscosity asphalt is better than that of LT high viscosity asphalt.4.Through the fluorescence microscope,it is found that DCLR high-viscosity asphalt can form part of colloidal network structure,and its viscoelasticity is better than LT high-viscosity asphalt.Short-term aging affects the solubility of the modifier and makes its compatibility worse.5.Through the mixture verification test,it is found that the high-temperature stability and water stability of DCLR high-viscosity modified asphalt mixture are better than those of LT high-viscosity modified asphalt mixture,but the low-temperature performance of LT high-viscosity modified asphalt mixture is better than that of DCLR high-viscosity modified asphalt mixture.DCLR high viscosity asphalt has excellent properties except low temperature performance,and can be used in areas with low temperature requirements,and its relative cost is relatively low.