关键词: 沥青路面, 水损害, 水气, 相对湿度差, 最大水气增量, 扩散系数

Abstract: As shown by engineering cases of moisture damage to asphalt pavement in arid areas, moisture damage is an importance source in addition to water in liquid form and vapor. For the asphalt pavement serving in the environment of dynamic change of moisture , relative moisture gradient is one of the prime drives for vapor movement. In order to investigate the water vapor transport in asphalt mixtures under different relative humidity differentials, the water vapor diffusion test was performed on asphalt mixture specimens under different relative humidity differentials by use of Gravimetric Sorption Analyzer (GSA). The test results indicate that the total diffused mass of water vapor accumulated in the test specimen (M(∞)) is linearly proportional to the relative humidity differential and that the total diffused mass M (∞) increases with the increase of the relative humidity differential. It is also found that the diffusivity D of water vapor in the test specimen is inversely proportional to the relative humidity differential under water vapor pressure only. After being converted to standard atmosphere pressure, the diffusivity D and relative humidity moisture are in linear positive relationship, which indicates that the relative humidity differential increases with the linear increment of diffusivity D .

Key words: asphalt pavement, moisture damage, water vapor, relative humidity differential, total diffused mass of water vapor, diffusion coefficient