Research On Application Of Hot In-place Recycling Technology In Liunan Expressway

With the continuous development of the economy,people’s demand for infrastructure has been increasing,and the scale of road construction investment has continued to increase.At present,the emphasis of road construction has shifted from the original road construction to maintenance,while the traditional milling and resurfacing method will generate a large quantity of waste asphalt mixture,which will cause environmental pollution and waste of resources.The Hot In-Place Recycling technology can make full use of the waste asphalt mixture,makeresource recycling realized,and save resources while protecting the environment.As a green environmental protection method,it is increasingly favored by people.In this paper,a section of the Liunan Expressway reconstruction and expansion project is used as a foundation for the Hot In-Place Recycling,and the technology is studied.The main work and achievements of the thesis are as follows:(1)Analysis of technical applicability of Hot in-place recycling technology.The traffic volume of Liunan Expressway was investigated,the road surface disease was analyzed,and the road condition was evaluated.The results show that the traffic volume of the Liunan Expressway has increased year by year,and the heavy traffic situation has become more and more austere.The evaluation results of PCI and PSSI indicate that the road of this section has sufficient strength and carrying capacity.(2)Evaluation of old asphalt mixture performance.The aggregate performance of old pavement was compared with its original performance.The parameters of the rotary evaporation method for recycling old asphalt were optimized,and the performance of the recovered old asphalt was analyzed.Using the trial-and-match method,from the perspective of the performance of asphalt and asphalt mixture combined with economic factors,the optimum dosage of regenerant is determined to be 5%(account for the asphalt content of original road).(3)Recycled mix design.On the basis of evaluating the old materials,three new materials with different proportions of the same grade are added,and the old material gradation is restored to three different types of gradations: KH-13,AC-13 and SMA-13.The asphalt mixture aggregate ratio were determined of each three grades.The road performance of the three recycled asphalt mixtures is synthesized eventually.The SMA-13 grade is recommended as the engineering grade.(4)The Hot in-place recycling technology construction control.In order to ensure the quality of the road after construction,the process is controlled from the aspects of heating,loosening,spraying regenerant,adding new asphalt mixture,paving and rolling.At the same time,it is proposed to strictly control the temperature during the process,and to check the performance of the mixture every day to monitor the quality of the construction process.(5)Evaluation of Hot in-place recycling construction project.The core sample compaction degree,flatness,water permeability detection and structural depth are tested on the post-work road surface,and the results meet the specification requirements.The feasibility of the maintenance scheme of hot in-place recycling technology in liunan Expressway was verified Finally,the economic and social benefits of Hot in-place recycling technology were analyzed.