| TOR improves the composition and properties of asphalt rubber. As an excellent energy-saving material with good road performance, TOR asphalt rubber has a wide range of applications. As a polymer material, TOR asphalt rubber is likely to aging in heat, light, oxygen, water and other factors. The aging of asphalt pavement will produce a series of diseases, and has a direct impact on the life of the road. Therefore, it is necessary to study the aging characteristics and mechanism of TOR asphalt rubber to provide a theoretical basis and technical support for the extended service life of TOR asphalt rubber pavement.This study selected the Donghai70#asphalt, Honglei60mesh bias tire crumb rubber and TOR to prepare TOR asphalt rubber. Preparation of mixing asphalt:stirring temperature:170±3℃, stirring rate:500rpm, stirring time:60min, the time of standing swelling after stirring:1h. According to the asphalt aging factors in actual use and study in domestic and abroad, this study considered factors such as heat, oxygen, light, water as the aging environment, selected equipments of the thin film oven aging test, pressure aging test and ultraviolet aging test for the aging simulation tests.By the comparing and analysing of performance of asphalt, asphalt rubber and TOR asphalt rubber before and after the heat and pressure aging, conclusions were drawn as follows:the softening point of three aged increase, ductility and penetration decrease; the addition of TOR weakens the impact of short-term aging on high temperature properties of asphalt rubber, and deteriorates low temperature cracking resistance after asphalt rubber aging. With the aging increases,135℃viscosity increases,170"C,180℃viscosity decrease. The results of dynamic shear rheological test showed that after aging the viscosity-temperature sensitivity of TOR asphalt rubber is stronger, but its rutting resisitance and fatigue performance is better, compared with asphalt rubber.Changed temperature and time of tests to research the influence of aging temperature and time to the TOR rubber asphalt aging performance.The results showed:The aging temperature has influence on the TOR asphalt rubber’s high temperature performance, but the law of technical indices are not clear, the aging temperature increased causes the low temperature performance of TOR asphalt rubber to drop. The aging time has an enormous influence on asphalt performance, the longer aging time is, the more obvious change of TOR asphalt rubber’s targets is, its aging is more serious.Aged the TOR asphalt rubber in different environments and analysed its performance before and after to research influence of aging environmental factor to the asphalt performance. The results indicated:The TOR asphalt rubber aged by ultraviolet ray is a process with some stages, the aging speed between5-10days is quite quick, the longer the ultraviolet aging time is, the more serious the aging is; The moisture intensified the asphalt aging, TOR asphalt rubber resists ageing caused by heat, oxygen and water better than the asphalt rubber; the influences of Heat, oxygen, water and ultraviolet to the asphalt aging are unnegligible.Through the infrared spectrum analysis and the nuclear magnetic resonance hydrogen spectrum analysis methods, analyzed composes and structural changes of the TOR asphalt rubber in aging to study the aging mechanism of TOR asphalt rubber.The infrared spectrum analysis showed:The TOR asphalt rubber aging in preparation process; Aging of the TOR asphalt rubber is an oxidation process, the carbonyl and sulphoxide functional group contents increased gradually; TOR delayed the oxidation rate of sulfur in asphalt aging process; The water dissolve part of aging product, promote the aging of TOR asphalt rubber. The nuclear magnetic resonance hydrogen spectrum analysis indicated:the chemical reaction process in TOR asphalt rubber is different with different aging conditions; TOR asphalt rubber takes the condensation dehydrogenation response of fragrant structure as the predominant type reaction in thermo-oxidative aging process, takes more splitting decomposition and isomerization reaction in photooxidation aging process; there would be aromatization, isomerization, decomposition condensation reactions and so on in TOR asphalt rubber aging process. |
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