Experimental Study On Key Technology Of Hot-recycling Melt Coating And Heating For Asphalt Pavement

The hot in-place recycling technology of asphalt pavement has been widely used as an economic and environmentally friendly road maintenance technology,but heating and melt coating are still the important reasons for the poor effect of the hot in-place recycling technology.Therefore,this paper mainly focuses on heating and melt coating problems for research in the hot in-place recycling technology.and through a case study on the engineering application of geothermal regeneration technology.This paper firstly summarizes the technical principles,process types,process flow and technical characteristics of the hot in-place recycling technology based on the extensive literatures at home and abroad,and introduces the hot in-place recycling technology construction equipment in detail.Aiming at the problem of melt coating of new and old asphalt in the hot in-place recycling technology,this paper designs an experimental method using infrared spectrum of asphalt as evaluation tool and square stone as tracer,and proposes old asphalt fluidity(P value)and regenerated asphalt mobilization.Degree(R value)is used as a measure to study the melt coating of new and old asphalt in the hot in-place recycling technology.The effects of different factors on the melt coating effect of new and old asphalt were studied by adjusting the ratio of new material addition,mixing temperature,mixing time and amount of regenerant.Aiming at the complicated factors affecting the heating of the pavement during the construction process and the difficulty of control,this paper designs a set of indoor heating experimental methods,through the modified indoor heating experimental device,drilling test board and temperature detector.The influence of factors such as oil-stone ratio,heating source temperature,heating source height and wind speed on the heating effect of asphalt pavement.In order to study the engineering application of the hot in-place recycling technology,this technology was used to repair the asphalt pavement in the xx road maintenance project.Including project overview,road status survey,mix design,construction and quality control.The effects of mixing temperature and mixing time on the performance of recycled mixture were studied experimentally.The mixing temperature and mixing time during the construction process were determined.The temperature of each link was strictly monitored during the construction process to ensure the construction quality.The results show that the addition ratio of new mixture has little effect on the melt coating of new and old asphalt;the mixing temperature has obvious influence on the melt coating of new and old asphalt;the addition of regenerant and the increase of mixing time can effectively improve the melt coating of new and old asphalt.The increase of the ratio of oil to stone and the temperature of the heating source helps to improve the heating effect of the heating plate on the asphalt mixture;the increase of the heating source height and the wind speed will reduce the heating effect of the heating plate on the asphalt mixture;and study the heat dissipation law of the test plate It is concluded that the time required for asphalt mixture to be paved to completion during the construction process should be as short as possible.As the mixing temperature increases,the void ratio of the recycled mixture gradually decreases,and the Marshall stability and residual stability gradually increase.The shortening of the mixing time leads to a significant increase in the void ratio of the recycled mixture Marshall test piece.