The Research Of Heat Transfer Efficiency In The Asphalt Pavement Heating Process

Hot in-place recycling(HIR)has many advantages,such as energy conservation,environmental protection,low interfere to traffic,good connection performance of asphalt pavement's interlayer and so forth,it has been applied widely in restoration of spoiled asphalt pavement.The one of key procedure of HIR is heating asphalt pavement,and enough heat can reduce the viscosity of asphalt,which facilitates the repair and regeneration of spoiled pavement.According to currently application of HIR,in virtue of lacking deep theoretical research to heating principle,heat transmission rule between the heating machine and the road surface and the heat transfer law of the asphalt pavement internal heat,which result in that it's hard to attain heat energy's transmission efficiency of asphalt pavement's regeneration process and also cannot realize maximum heating efficiency in the process of HIR,thereby the problem cannot solved that high efficiency and energy saving in regeneration of asphalt pavement.Thus obtained law of heat energy transfer in the process of heating asphalt pavement,which can better solve the problem of heat transmission efficiency in road surface regeneration and realize high efficiency,energy saving heating.This thesis is based on the Project Study on heat transfer mechanism of the infrared continuous heating process of Asphalt Pavement Based on spectral analysis supported by NSFC,combined with the theory of heat transmission and the common structure of asphalt pavement to established the inner heat transfer model of the asphalt pavement,and deducted the heat transfer equation of the asphalt pavement.Through MATLAB that based on the finite difference method to numerically simulate heat energy's transfer process of traditional asphalt pavement's heating technology and "multistep" heating technology,and designed a brazen heater to simulate the test of heating asphalt pavement,built test platform that can simulate asphalt pavement heating and test system to test the heat transfer rule between heater and asphalt pavement.The results shown that though brazen heater simulated the test of heating asphalt pavement which validated the correctness of though numerical simulation calculated transfer process of thermal energy;analyzed the test result of thermal energy's transfer law between heater and asphalt pavement and got the efficiency of thermal energy output of the infrared radiation heater's surface is 89%,the efficiency of radiant thermal energy transfer between the heater and the asphalt pavement is 78.9% and the heat absorption efficiency of the asphalt pavement surface is 81.7%;though analyzed the result of numerical simulation of traditional asphalt pavement heating technology and "multistep" heating technology and got a conclusion that is different heating processes can affect heat transfer,Finally got a conclusion that "multistep" heating mode is the most efficient and heat energy saving‘s regeneration heating mode.