Expressway Asphalt Pavement Early Water Damage Prevention Measures

The early moisture damage of asphalt pavements has been one of the uppermost distresses in expressway, how to prevent it efficiently has been a problem that highway engineers pay much attention to. The paper analyzed the mechanism of the early moisture damage on the basis of survey, had carried out a series of laboratory tests to study the prevention measures from three aspects, that were gradation of the surface course and compaction capacity and the anti-stripping performance of hydrated lime qua anti-stripping agent. The results showed that the gradation, which designed by volumetric methods, has perfect water-stability and other pavement performance also can meet the demands of expressway. By integrating compaction capacity and pavement performances, the optimal ratio of the structural layer thickness to the maximum particle-size is 2.5. The water resistance of the mixture added amine type anti-stripping agent attenuates severely after long-term aging, but the mixture added hydrated lime not only can improve obviously the capacity of water resistance, but also has perfect long-term pavement performance. It is a superior anti-stripping agent.