Analysis And Research Of Temperature Field In Pavement Of Thermal Radiation Asphalt Concrete

It has been concluded that the high temperature in bituminous pavement could cause urban heat island effect and reduce the quality of the environment. In some degree, it may lead to damage of bituminous pavement and property loss. The internal temperature field of asphalt mixture which can reduce road and environmental temperature was studied in this paper, which will provide theory basis for the engineering application in the future.Three different kinds of Infrared radiant materials (IRM), which were marked withⅠ,ⅡandⅢ, used to instead of the limestone ore fines as the fill of asphalt mixture, of which the IRM content was 0%, 6% and 12%, and made by different proportion, and seven kinds of Marshal Test piece were prepared. Furthermore, temperature distribution in the Marshal Test piece was researched with theoretical and experimental methods.A temperature measurement system was designed to get the temperature on different layer at the same time in the Marshal Test piece, which was set as four layers. To analyse the temperature of rising, dropping and range, and the equilibrium temperature of different layers showed that all sorts of IRM had played a part of the cooling effect. In heating process, the infrared pieces that had good performance in thermal radiation properties were well behaved in cooling process. The internal infrared powder launched infrared rays to accelerate internal heat conduction, which made internal temperature of pieces decrescent. By the temperature of asphalt surface reducing, the heat storage of Marshal Test piece was lower. So the high temperature damage of bituminous pavement could be prevented essentially. Among all the pieces, 12% IRM content pieces of typeⅢhad the most obvious effect, whose equilibrium surface temperature was 8℃lower than 0% IRM content pieces when the temperature gradually, and the difference in temperature between surface and bottom was 5.21℃lower than 0% ones. In dropping curves, we also found the same result. 12% IRM content pieces of typeⅢwas 6℃lower on surface and 2.09℃lower in internal than 0% IRM content pieces.A three-dimensional numerical model of transient temperature field with the second boundary in asphalt pavements and the model of surface heat transfer conditions were proposed. It was shown that the surface equilibrium temperature was inverse proportion to long-wave emissivity. In order to get layered distribution model of pieces inner temperature field, the temperature distribution of Marshal Test piece under heating was simulated by FLUENT after the various factors that influenced the pavement temperature field and material thermal physical had determined.The distribution of internal temperature field and the comparison between the test data with the theory data were studied in this paper. The results showed that the experimental data consistented with the theoretical, which proved that the thermal radiation asphalt mixture could reduce the temperature of the pavement effectively.