Study Of Numerical Simulation Of Semi-rigid Basal Asphalt Pavement Surface Temperature Field And Temperature Stress

The pavement structure completely exposes in the natural environment. It bears the influence of atmosphere, which continues changing, like solar radiation, sky radiation and ambient temperature. The solar radiation and the sky radiation are partially reflected from the road surface; the rest is absorbed and transferred into heat. This heat and the ambient temperature superimpose and accumulate large amount on road surface, which leads to heat conduction effect that makes the heat spread from high temperature to low along the thickness. The surface temperature keeps changing in the day, which causes instable heat current in inner road surface.From mechanics analyzing, because of the instable heat current inside the pavement, each part of the pavement will expand or contract with the temperature getting high or low. But because of reciprocal bond of each part of the layered pavement, this deformation can not proceed freely, so, the heat stress appears, when it exceed the tensile strength of the materials used in the road surface, the asphalt pavement will crack. From the analysis of material science, the basic semi rigid asphalt pavement is sensitive to temperature, and the strength, stiffness and temperature contraction capacity of the asphalt mixture will change with different temperature. Due to this nonlinear relationship, the analysis of temperature field and temperature stress of the basic semi rigid asphalt pavement gets rather complex. The experience of long time road using make people gradually realize that the temperature state of the road will greatly affect the strength and using effect of the pavement.In order to study the crack problems of the basic semi rigid asphalt pavement in HuaiNan district accurately and in detail, the temperature field and temperature stress of the pavement in this district should be firstly determined, and the most direct method is to conduct practical observation in representative areas. This task will cost large amount of man power, time and other things, but the possibility of meeting the extreme temperature is low although the practical observation is conducted all year around.Therefore, this article collect many relating documentations and research achievements domestically and abroad, and study and conclude the identification of phenomenon and mechanics of the early stage failure of the temperature contraction crack of asphalt pavement. According to the area and position the pavement exists, and with the help of standard meteorological data, the temperature stress is calculated in use of ANSYS on the basic principles of heat transmission and meteorology. During that course, the temperature is analyzed by numerical modeling in one or more cycle periodical time of the typical climate as the load of the asphalt pavement, and the daily changing rate and the distribution of the pavement are gained which offer reliable basic data to the crack analysis. Beginning with building much more practical theory system and computation method, the analysis of the quantitative relationship between the mechanic behaviors of the asphalt and each influencing factor is conducted in order to offer more accurate prediction to the using life of the asphalt pavement. To improve the crack-resist capacity of the asphalt pavement, take immediate measures, and improve the existed pavement designs, this research is of great significance.