| The asphalt pavement performance is greatly affected by the environment.Because of thespecial climateof Tibet，the performance requirementsof asphalt mixture are different fromgeneral area. While the formerresearch on asphalt mixture is aiming atsecond-class highwayand below, there is no experience about the design of high-grade highway. In this study,combining with engineering practice, the effect of different types of asphalt, gradationtypeand nominal maximum aggregate sizeon asphalt pavement performance is analyzed on thebasis of the existing research on asphalt binder and asphalt mixture in high altitude area,which is mainly to low-temperature cracking, aging and freezing and thawing. The selectionmethod ofasphalt types and gradation rangeis put forward to meet the requirements of highlevel asphalt pavement, which serves the engineering construction.In Tibet, the temperature lowyear round, the temperature gradient is high, and the solarradiation is strong, frost weatherappear frequently, which demand that the low temperatureperformanceandwater stabilityof asphalt pavement must be very good. At the same time, dueto global warming, heavy traffic and channel traffic ofhigh-grade highway,high temperatureproperties cannot be ignored. Through thebending test of small beam,immersion marshall test,freeze thaw split test and rutting test, the effect of different types of asphalt, gradationtype andnominal maximum aggregate sizeon asphalt pavement performance is analyzed. The resultsshow that: selecting a compound modified asphalt and framework dense structure willcontribute to ensure the pavement performance of asphalt mixture, and the upper layer andmid-surface of asphalt pavement is suggested to adopt the modified asphalt, and the intensityratio of frozen and melted of asphalt mixture should greater than85%. On this basis，themineral aggregate gradation of mixtures for pavement surface of high-grade highway isrecommended, and the design requirements of asphalt mixture is proposed. |
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