The project identified patterns of change in material properties caused by daily and seasonal changes in temperature and moisture and developed recommendations for using falling weight deflectometer (FWD) data to detect the onset of spring thaw and the end of the thaw-weakening period.

Because of the effects of temperature and moisture on pavement materials, the variation in insitu material properties of pavement layers must be considered in evaluating the effective structural capacity of the pavement. However, the relationships between temperature and moisture conditions and material properties are not well documented. Therefore, there is a need to identify the relationships between daily and seasonal temperature and moisture conditions and the insitu material properties of pavement layers and to develop methodologies for estimating the pavement's daily and seasonal structural capacity.

The research included a review of literature relevant to the effects of temperature and moisture on pavement materials and seasonal structural capacity, review and analysis of the data available from the Long Term Pavement Performance (LTPP) studies, and performance of analytical investigations. LTPP data were analyzed to identify patterns of change in insitu pavement material properties and to determine relationships between these properties and daily and seasonal changes in temperature and moisture. The analytical investigations were performed to identify relationships between these properties and the daily and seasonal structural capacity of flexible and rigid pavements. The agency final report is available as NCHRP Web Document 60.