Modeling of non-stationary temperature mode of a multi-layer road structure

The article presents an analysis of changes in the temperature regime in the road pavement and soil foundation of the section of the road “Kyzylorda-Shymkent” based on the results of experimental studies and calculations on a mathematical model. Experimental temperature measurement was carried out using special sensors from the 1st till the 31st of July in 2014. Theoretical calculations were carried out on a one-dimensional model of non-stationary thermal conductivity in a multilayer road structure developed by authors. It accounts thermo conductivity properties and thermo resistance of materials of all layers of a pavement structure and subgrade, and also thermo fluxes of convection, solar radiation and thermo flux from a pavement surface. By comparing the experimental and calculated values of the temperature at the points of the pavement, the adequacy of the proposed mathematical model of the non-stationary temperature regime was proved. An adequate mathematical model gives possibility to predict temperature regimes in a pavement structure and subgrade of a road at different changes of air temperature and weather conditions. Results of the experimental measurements showed that in the south region of the republic in July in the afternoon air temperature reaches 40ºC. Its daily average value was more than 30ºC. And a temperature of the asphalt pavement surface exceeds 50ºC, which is more by 15ºC than air temperature. A temperature in layers of the subgrade decreases with depth. For example, at depth of 15 cm from the pavement surface a temperature is 8-10ºC lower than the pavement surface temperature.