Some Insight into the Mixture Design of Large-Stone Asphalt Mixture for Airport Pavement

Resumo

In Japan recently large-stone asphalt mixtures have been introduced into the airport asphalt pavement to reinforce the pavement structure. So far they have been used as the base layer and/or the subbase layer materials. To reduce the rutting damages further and to prevent stripping between layers, it is expected to use the large-stone asphalt mixtures as the surface-base layer material. However, the raveling and cracking durability have not been thoroughly clarified. Therefore in the study a series of laboratory tests were conducted on the large stone asphalt mixture to evaluate the raveling and cracking characteristics in detail. For example, raveling tests were conducted to measure the groove deformation. Atmospheric exposure tests were performed to evaluate the asphalt deterioration characteristic. Same tests were also carried out on the conventional type asphalt mixture. Based on the test results, this paper focuses the effects of air void ratio in the large asphalt mixture on the bending strength-deformation, the raveling characteristics and the asphalt deterioration. It is found that there are suitable ranges of air void ratio to match the bending and raveling resistance to those of the conventional type asphalt mixture. Then the paper also suggests the appropriate air void ratio in the large-stone asphalt mixture for the surface-base layer.