| With the rapid development of China’s highway industry,asphalt pavement has become an increasingly high proportion of highways due to its many advantages.Asphalt is a relatively large material in asphalt pavement construction.Its production,processing and mixing have always been concerned by countries around the world the key of.Asphalt pavement will be affected by various environments and vehicle loads during use.As time goes by,the pavement ages and many diseases occur,resulting in a sharp decline in road performance,which not only shortens the service life,but also increases the cost of road maintenance.In short,the aging of asphalt has a great influence on the performance of asphalt pavement.Therefore,it is very necessary to study the aging behavior and aging characteristics of asphalt.First,three types of substrate asphalt and SBS modified asphalt with different film thicknesses(0.5mm,1mm,and 2mm)were selected for outdoor UV aging.The aging time lasted for 6 months.Asphalt samples were aged for 1,3,and 6 months.Its general properties and rheological properties.The research results show that the softening point growth rate is faster at 30 days before outdoor UV light aging,and gradually flattens with the aging time;outdoor UV light aging has a greater impact on the low-temperature performance of asphalt.After 6 months of aging,the ductility of matrix asphalt is 0.Through DSR and BBR tests,it is found that when the aging time is the same,the outdoor UV aging degree of the asphalt film with a thickness of 0.5mm is the largest,and the film thickness of 1mm is equivalent to 2mm.Taking Changsha area as an example,the conversion relationship between indoor and outdoor UV light aging time is obtained based on the principle of equal ultraviolet radiation.One month of outdoor aging of asphalt is equivalent to indoor simulated UV light irradiance of 11.8W/m2 for 225.4h.The effects of film thickness,UV irradiance,and water immersion status on indoor UV aging were studied by orthogonal experiments,and it was found that film thickness had the greatest effect on UV light.Secondly,the effects of temperature,time and sample film thickness on asphalt TFOT aging and PAV pressure aging are studied.The test results of the three major indicators show that the softening point of the base asphalt increases with the increase of aging temperature and time;the change trend of SBS modified asphalt is not monotonous,but the overall trend is an upward trend.The penetration and extension of the two types of asphalt Degree decreases with increasing aging temperature and time;the film thickness of the sample has little effect on TFOT aging and PAV aging.Finally,the Fourier transform infrared spectrometer and scanning electron microscope were used to analyze the microstructure and morphology of the asphalt under different aging methods.The analysis results showed that carbonyl and sulfoxide functional groups appeared in the asphalt spectrum chart under different aging methods,indicating different In the aging mode,the asphalt has undergone oxidation reactions.After aging,the asphalt surface becomes rough,wrinkled,and hollow. |
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