Study Of The Causes Of The Moisture Damage And The Gradation Design

The early moisture damage of asphalt pavements has been one of the uppermost distresses in expressway, it is necessary to study the causes of the moisture damage and to effective prevent and treatment.The paper analyzed the causes and the mechanism of the early moisture damage, had carried out a series of laboratory tests to research the gradation of the surface course, and pointed the prevention measures from the compaction capacity and the mixture segregation and the anti-stripping agent.The paper studied the pavement performance of the mixture gradation, which designed by Superpave methods. The results showed that the gradation not only has perfect water-stability, but also can meet the demands of expressway. By considering the compaction capacity and the pavement performance, the optimal ratio of the structural layer thickness to the maximum particle-size is 2.5. And pointed out that during construction the mixture segregation is the causes of the local damage, it is necessary to resolve the mixture segregation and the nonuniformity.In addition, the paper also pointed the other proposed measures to prevent the moisture damage of asphalt pavements, such as adding anti-stripping agent, improving the standards of compaction, seting pavement drainage system.