Study On Hot In-place Recycling And Its Heating Process Of Asphalt Pavement

In the end of 2015,the total length of highway has amount to 4577,000 kilometers in our country,the early built roads has already entered great or middle repairing period and the task of maintenance and upgrade is getting heavier and heavier.Been as an save and environmentally-friendly conservation technology,hot in-place regeneration of asphalt pavement acquire attention.While at present,the domestic research on hot recycling technology is far from enough,so this paper will further analyze the technology.It is important to improve the construction quality of pavement.First of all,this paper analyze the aging mechanism of the old asphalt pavement,and put forward the index of aging performance and aging degree,Meanwhile,the regeneration mechanism of the asphalt mixture is analyzed.The characteristics of the typical modes of the hot regeneration and its process are analyzed,and the method of selecting the corresponding regeneration process for different old road damage is described.Temperature is a direct reflection of the heating effect of the hot regeneration.Therefore,this paper focuses on the study of the heating temperature field of the hot regeneration asphalt pavement.Based on Fourier's law of heat conduction and energy conservation principle,the one-dimensional unsteady thermal conductivity model of asphalt pavement is established,and the finite difference method is used to solve the partial differential equation of heat conduction.Combined with the hot regeneration equipment produced by a company,the model is used to simulate the temperature by computer programming.The influence of different environmental factors on the heating temperature field and the distribution characteristics of time-depth-temperature in the heating process are obtained by computer simulation,and the results were discussed and analyzed.Through this mathematical model,the temperature of each layer of asphalt pavement at different heating times and the time required to reach the construction temperature can be calculated,which can guide the actual construction.Finally,this paper combined with the hot in-place regeneration project of Hongwu North Road in Nanjing,the main factors of affecting the construction quality such as regeneration temperature,regeneration mixture gradation and regeneration agent dosage,the surface evenness of regeneration road and compaction quality are analyzed and studied.The quality of the construction process will directly affect the performance of the asphalt pavement after hot regeneration,so the quality of each link will be strictly control in the actual construction.