Thermal Diffusivity Field Determination Based on Fourier Series

Abstract:

Pavement temperature field was abstracted as onedimensional transient heat conduction equation.Fourier series that compatibility with the equation was obtained by separation of variables.Then instantaneous temperature distribution of one dimensional layered body in terms of known interface temperature was derived based on Fourier series.The Newton method that backcalculation the thermal diffusivity of pavement material in related to measuring temperature distribution in field was presented.In cooling process as pavement temperature changes along the depth monotony,Fourier series with 50 items can attain the accuracy of 0.01℃.Results derived from measured data show that thermal diffusivity of top asphalt concrete layer is larger than that of bottom layer,with 0.002 4 m2·h-1 for AC16 and 0.001 6 m2·h-1 for AC25,which is lower than most of the laboratory measured values.