| With the development of economy, the traffic pressure increase a lot. At the same time, the development of automobile industry caused a lot of waste tires which is difficult to deal with. It caused great pressure to the environment protection. In recent years, crumb rubber modified asphalt exhibit excellent performances on the road construction. It plays an important role in the improving of highway quality in our country, and it provides a new way to deal with waste tires. But the rubber modified asphalt still has many defects and limitations.In this paper, we used devulcanized rubber to prepare modified asphalt. 20 mesh and 30 mesh of waste rubber powder made by Zhongjiao were used, and devulcanized by a co-rotating twin-screw extruder. We test the sol content of devulcanized rubber, then explore the rubber in GPC, FTIR and DSC. Binzhou (AH-70) asphalt is selected, and devulcanized rubber modified asphalts is prepared using wet process. We test the three indicators of the asphalt. Then analysis the microstructure of modified asphalt by using rubber process analyzer (RPA) analysis and fluorescence microscopy. Through the analysis of experimental result, the the conclusions of the research are described as follows:Increasing the temperature of twin screw extruder and reducing the speed can improve the rubber devulcanzation effect. The best temperature is 280℃, the devulcanzation degree can be controlled by changing speed. The best dosage of devulcanzation activator(580) and pine tar are 2% and 4%.The dosage of devulcanized rubber in modified asphalt can be 30% or more.The rubber with higher sol content will gives the modified asphalt lower viscosity, and makes the storage stability much better. But the softening point worse than before.We use vulcanized and devulcanized rubber together to prepare modified asphalt. We hope the modified asphalt will has better performance. In fact, the experiment prove our guess. |
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