| Recently, maintenance of asphalt pavement has been important. To evaluate the aging level of asphalt pavement in service, it is necessary to take asphalt core samples from pavement and then extract asphalt binder from these cores. Authors have proposed a simple evaluation method of the asphalt mixture by infrared spectroscopy (IR) and revealed that the spectrum of the asphalt binder coated asphalt mixtures without extraction showed the aging peak. In this investigation, it was attempted to clarify the relationship between surface and internal aging of asphalt pavement in order to establish the method to predict the internal aging from characteristics of the surface of asphalt pavement. The difference of the aging level of the asphalt mixture in the depth direction was measured by penetration test, rheological measurements, IR and TLC-FID techniques. According to results of the carbonyl index obtained by IR test and other physical properties, it was confirmed that the carbonyl index was correlated with the penetration. Also, it was found that the progress of aging varies in the depth direction. Especially, it was seemed that the factors inducing the aging were different among the surface, surface course and binder course. It was discussed for each aging mechanism of the surface course and the binder course. |
