The purpose of this study was to investigate the changes in properties of asphalt concretes for surface courses of airport asphalt pavements as a result of the
cracking associated due to effects such as temperature changes.
　Conditions of surface courses in actual airport pavements were investigated from the aging point of view. The investigation revealed the rate of change in aging
in relation to depth from the surface, the age-associated alternation of asphalt in asphalt concretes, and the influence of aging of asphalt concretes on their mechanical properties.
　Furthermore, a series of model tests were carried out to clarify the aging phenomena of asphalt concretes. The tests were made to find out the changes in mechanical properties of asphalt concretes, and the changes in physical and chemical properties of recovered asphalt, by two aging processes of 70°C heat curing and exposure in natural conditions. The test reuslts showed the difference between 70°C heat curing and exposure in natural conditions with respect to aging mechanism, and clarified the influence of asphalt type and aggregates on aging behavior of asphalt concretes.