Compatibility Of The Elastomer-Asphalt System Effected By The Radiation Of Microwave

Crumb rubber modified asphalt(CRMA) is studied, in order to promote the compatibility of crumb rubber and asphalt,as well as to improve the performance and stability of CRMA by the radiation of microwave. This paper studied crumb rubber's pretreatment by the radiation of microwave under different conditions, so as to develop new methods to modify asphalt. The experiments include three parts:In the first stage,we investigated the microwave degradation of crumb rubber at the presence of different solvents. The degradation degree of crumb rubber was measured by the toluene solubility of crumb rubber and the crumb rubber's apparent viscidity soaked by furfural drawn oil. The results showed that the toluene solubility of crumb rubber increased as the dipolar moment of solvent greater,and the largest solubility was the dry crumb rubber without solvent. The result of crumb rubber's viscidity soaked by furfural drawn oil showed that the best time of radiation was 0.5-2 min at 540 W. The radiation of microwave improved the compatibility of crumb rubber and asphalt.In the second stage,the asphalt modified by dry crumb rubber which was pretreated by microwave was studied. We found that even the same size crumb rubber had different sensibility to microwave, while their sources, treatment process, etc were different. To speak generally,the dry crumb rubber pretreated by microwave improved the asphalt's ductility with a little lower soft point, compared with the normal preparation process. To the first passel crumb rubber, the CRMA with the best stability was prepared in such conditions: crumb rubber 20% according to asphalt, compatibility solvent7.3%, linking agents 0.8%, and the pretreated time was 1min.In the third stage, crumb rubber soaked by furfural drawn oil was radiated by microwave and then used to modify the asphalt. The results showed that the soft point (approximately 51℃), viscosity (approximately 2500 mPa·s) and penetration number (approximately 110 Units) varied little as the radiation time longer (within 3 min). But the ductility was likely to be conic according the radiation time. As the radiation time longer, the ductility first increased and then dropped. Its highest point appeared at 1.5 min,the ductility increased to 20.5 cm from 17.5 cm(without radiation). The radiation of microwave improved the ductility of CRMA greatly. The best radiation time is 1.5 min, when the microwave power was 960 W, to the crumb rubber soaked by furfural drawn oil (crumb rubber : furfural drawn oil = 15 : 10 ).