Laboratory Experimental Study On Thermal Regeneration Of Waste Asphalt Pavement In Cold Seasonal Frozen Area

China's highway mileage base is large,and the second and above are basically asphalt pavement.The service life of asphalt pavement is generally 10-15 years,and every 10 years,it is necessary to carry out large and medium repairs.Therefore,China produces a large amount of waste asphalt pavement every year,and the distribution areas in China's cold regions and seasonal frozen soil regions are relatively wide.Therefore,this paper has carried out the use of climate zoning and seasonal frozen soil partitioning on asphalt pavement.According to the zoning results,the technical requirements for road performance and frost resistance of reclaimed asphalt mixture in cold seasonal frozen area were designed.The recycling of waste asphalt,the design of mineral aggregate composition,the mix design of recycled asphalt mixture and the road performance and frost resistance of recycled asphalt mixture were studied.The economic and environmental benefits of recycled asphalt mixture were analyzed.According to the research results,the following conclusions are drawn:(1)The asphalt content in the asphalt pavement is 3.58%,and the penetration and elongation decrease,the softening point rises,and the coarse aggregate is refined,which indicates that the asphalt pavement has deteriorated(2)Compared with the high-grade asphalt recycling of the waste asphalt,the regenerant is more suitable for the regeneration of the waste asphalt,and the optimum amount of the regenerant is determined to be 17%.(3)Compared with No.90 asphalt and No.90 aged asphalt,recycled asphalt has good low temperature crack resistance and high temperature stability,and is more suitable for cold and frozen areas.(4)The 100% regeneration of the waste asphalt pavement was studied,and the optimum regenerant incorporation was determined to be 1.42% of the total mass of the recycled asphalt mixture.Increasing the amount of regenerant above or below1.42% reduces the road performance and frost resistance of the reclaimed asphalt mixture.(5)Compared with ordinary asphalt mixture,the old material content is: 20%,30%,40%,50% of the recycled asphalt mixture.In addition to the high temperature stability energy higher than the ordinary asphalt mixture,the water stability of the recycled asphalt mixture Low temperature crack resistance and frost resistance are lower than ordinary asphalt mixture.The higher the amount of old materials,the better the high temperature stability of the asphalt mixture,and the worse the water stability,low temperature crack resistance and frost resistance.(6)The recycling of waste asphalt pavement saves a lot of asphalt and mineralmaterials,and the higher the amount of old materials,the lower the material cost of recycled asphalt mixture.Therefore,the recycling of waste asphalt pavement not only reduces the material cost of asphalt pavement construction,but also realizes the recycling of asphalt and mineral resources,reduces energy consumption and environmental pollution,and has good economic and environmental benefits.