پیش بینی دما برای تراشه های آسفالت با لایه آسفالت ضخیم Temperature predictions for asphalt pavement with thick asphalt layer

1. Introduction Functional as well as structural performance of asphalt pavements can be greatly affected by pavement temperatures. At low temperatures, asphalts stiffen and the cracking of asphalt layers is accelerated due to shrinkage. At high temperatures, asphalts soften and the distortion of asphalt layers is increased due to bleeding of asphalts [1,2]. Therefore, it is vital to know the range of temperatures over which an asphalt pavement will be subjected. This importance calls for special attention and interest in research to develop procedures for pavement temperature predictions. Approaches for temperature predictions within asphalt pavement have been proposed by a number of researchers. These approaches can be divided into two categories. One is analytical approach, which is based on the heat transfer theories and thermal properties of asphalt pavement. The other is statistical method, which uses regression models to obtain the relationship between measured pavement temperatures and climatic data. In 1975, among the first researchers taking analytical approach, Barber [3] presented a method for calculating maximum pavement temperatures from weather report and thermal diffusion theory. Based on his pioneering work, Dempsey [4] developed an analysis program named Climatic-Materials-Structural (CMS) model in 1970. The CMS model was improved by Thompson [5] in 1987, and temperatures were computed by a one-dimensional, transient finite-difference heat transfer model with climatic data input. In 1993, Solaimanian and Kennedy [6] discussed an analytical approach for predicting critical temperature extremes in pavements. Similarly, it uses the theories of heat and energy transfer. Based on their approach, Hermansson [7] proposed a simulation model to predict maximum pavement temperatures in 2000. Although all the models mentioned above do calculate temperatures with reasonable accuracy, the large number of inputs makes approach rather cumbersome and hard to use.