Study On The Performance Of High Content Plant Mix Hot Recycled Asphalt Mixture

Asphalt pavement construction has entered the stage of building and maintenance simultaneously.Plant mixing and hot recycling can make good use of the recycled materials of the original pavement,improve the quality of the mixture by improving certain technology,so as to pave on the original pavement,not only save energy,but also effectively save raw materials.How to improve the content of rap materials and ensure the construction quality has become the research of the current road construction A key.In view of this,in this paper,based on the reconstruction quality improvement project of the South Branch of Dongcheng Avenue in the old urban area of Dazu District,Chongqing City,through the use of warm mix recycling technology,the high content plant mix hot recycling technology is improved,and the preparation of warm mix recycling agent and the performance of warm mix recycled asphalt mixture are studied.The research results have certain theoretical value and practical engineering significance.The main research contents and achievements are as follows:According to previous studies on the mechanism and analysis of asphalt aging,the corresponding raw materials were selected by changing the aging functional groups of asphalts.According to the orthogonal test,a combination of 100 g viscous flow oil +14% epoxy oil +2% resin +2% anti-aging agent +3% warm mix reclaiming agent was selected to get the best warm mix regenerating agent for improving the penetration degree of aging asphalt,and the properties of asphalt before and after warm mix regeneration were analyzed.And the performance of warm mixing regenerant.The results showed that the simulated aging test showed that the peak positions of the infrared spectra of the reagents before and after aging were similar,and no aging occurred,indicating that their aging resistance was superior.The phase change temperature could reach 240 degrees centigrade,the ignition point could reach350 degrees centigrade,and the high temperature stability was superior.According to the relevant formula,it is determined that the addition of warm recycling agent to the aged asphalt is about 4%.Warm recycling agent and aged asphalt are used to prepare warm recycling asphalt,and the performance of warm recycling asphalt binder is analyzed.The results show that the penetration and softening point of the aged asphalt can be well recovered by the warm mix regenerant,but the ductility performance is not completely recovered,which shows that the warm mix regenerant has certain regeneration ability;through the viscosity test,it can be seen that in the asphalt mixture mixing,the temperature can be reduced by about20 ℃ for mixing and discharging,and the compaction conditions can be met by keeping the temperature at about 120 ℃;through DSR and DS C test shows that the quality grade of recycled asphalt is pg-64-16;DSR shows that the complex modulus of recycled asphalt decreases sharply at first and slowly with the increase of temperature;the phase angle increases gradually,indicating that the elasticity of recycled asphalt decreases with the increase of temperature.According to the recycled asphalt mixture,the aged asphalt is obtained by extraction test,and then the recycled content is determined according to the warm mix recycling agent and aged asphalt.Then,the high content warm mix recycled asphalt mixture is prepared by selecting 50%,60% and 70% rap content,and the performance of warm mix recycled asphalt mixture is analyzed.The results show that the addition of warm mix recycling agent to the aged asphalt is about 4%;with the increase of rap content,Marshall stability and high temperature performance are stronger,but flow value,low temperature performance and water stability performance are gradually reduced.According to the experimental study,it is found that the 60% rap content of warm mix recycled asphalt mixture can give consideration to both performance and economic type.Through the research of the solid engineering,the high content of warm mix recycling asphalt concrete pavement is made by using the warm mix recycling technology,and the value of the high content of warm mix recycling technology is analyzed systematically.The results show that the temperature of rac-20 asphalt mixture produced in the mixing station is about 15 ℃ lower and the mixture is discharged.After the final mixture is compacted,the performance of the mixture is tested by a third-party testing organization to meet the specifications.According to the production mode of the mixing station for the mixture,the "wet" delivery of the temperature mixing regenerant and the control of the production mode of the mixing plant are studied,and the mixture with better performance can finally be obtained,which is a large-scale mixture The feasibility study is made to popularize the technology of high content warm mixing regeneration.