A simple method is proposed to calculate the maximum pavement temperature profile on the basis of maximum air temperature and hourly solar radiation. The method was developed to be used mainly for Strategic Highway Research Program binder and mixture specifications and as a quick method of determining maximum pavement temperature for various regions in the United States and Canada. The method is based on the energy balance at the pavement surface and the resulting temperature equilibrium. Reasonable assumptions are made regarding thermal properties of the asphalt concrete. The accuracy of the method was tested by applying it to some field cases for which measured pavement temperatures were available. In 83 percent of the cases, the proposed equation predicted the pavement temperature within 3 C, which is well within reasonable limits, considering the numerous uncertainties that exist in material properties, accuracy of measurements, variability of environmental factors (wind, sunshine, etc.), and inclination of the pavement surface in receiving radiation.

The binde. r and mixture specifications that are in development under the Strategic Highway Research Program (SHRP) Asphalt Research Program are tied to maximum and minimum pavement temperatures for various locations in the United States and Canada. Therefore, it became necessary to seek a quick and efficient way to determine the maximum pavement temperature profile with sufficient accuracy for various regions. Barber (J) was among the first researchers to propose a method of· calculating maximum pavement temperature from weather reports. He applied a thermal diffusion theory to a semi-infinite mass (pavement) in contact with air. In his theory, solar radiation was considered on the basis of its effect on the mean effective air temperature. The resulting equation is simple. However, because the method uses total daily radiation rather than hourly radiation, the calculated maximum pavement fomperature with this model is the same for different latitudes having the same air temperature conditions and the same total daily solar radiation. Another procedure was suggested by Rumney and Jimenez (2). They developed some empirical nomographs to predict pavement temperature at the surface and at a 2-in. depth as a function of air temperature and hourly solar radiation. These graphs were developed on the basis of data collected on pavement temperature in Tucson, Arizona, in June and July along with data collected on measured hourly solar radiation. Dempsey (3) developed an analysis program, named climaticmaterials-structural (CMS) mo&l, that is based on heat trans-