Analysis Of Moisture Diffusion Characteristics Of Asphalt Concrete Under The Influence Of Temperature And Humidity

With the rapid development of technology and economy,the highway used in urban and rural areas are more and more common,most of which is asphalt pavement,further more the water damage is one of the most common damages to asphalt pavement.Even in the arid areas with so little rainfall,besides the liquid water produced by rainfall,the gaseous water in the air can also cause water damage to the asphalt pavement.And the content of gaseous water in the air will be affected by temperature.Therefore,the weight reduction method was used in this paper to discuss the characteristics of water vapor diffusion of asphalt concrete under the influence of temperature and humidity.The main work of this paper is as follows:1.According to the data published by China Meteorological data Network,the characteristics of atmospheric temperature and humidity environment in China are analyzed,and the experimental indexes of water vapor diffusion of asphalt concrete under the influence of temperature and humidity are determined.According to the linear relationship between absolute humidity,temperature and relative humidity,the temperature and relative humidity in the final experiment are determined.2.In order to solve the problem that the experimental environment can truly simulate the external environment of asphalt pavement,a water vapor diffusion experimental device(environmental experimental box)is designed and assembled to simulate the real environment of asphalt service accurately,and speed up the experimental process.3.through the method of weight reduction,the adhesive specimens(including granite,bluestone,marble),bonded specimens(granite bonded specimens,marble bonded specimens,bluestone bonded specimens)paste bonded specimens(granite paste bonding specimens),Water vapor tests were carried out on marble paste bonded specimen,blue stone paste adhesive specimen,mixture(fine aggregate with 10.8% oil ratio)and asphalt concrete.In a certain period of time,because of the difference of humidity and temperature,the water vapor content in the air is also different,and the amount of water vapor exchange through the stone is measured.According to the water vapor diffusion formula,the water diffusion coefficient can be calculated under the conditions of each test temperature and humidity.Through the comparison and analysis of the water vapor diffusion coefficient,the results show that the water vapor diffusivity becomes more and more obvious with the increase of the temperature at different temperatures,and the water vapor diffusion coefficient increases with the increase of the temperature.With the increase of relative humidity,the external humidity of the specimen gradually increases to the internal humidity of the specimen,so that the amount of water vapor exchange becomes less and less,so the diffusion coefficient of water vapor decreases.Under the coupling of temperature and humidity,there is an exponential relationship between the water vapor diffusion coefficient and the absolute humidity.4.Combined with the actual environment of asphalt mixture in this paper,the relationship between water vapor diffusion coefficient and temperature,relative humidity and absolute humidity is analyzed by weight reduction method.The results show that increasing the ambient temperature,increasing the relative humidity and absolute humidity in the environment will affect the process of water vapor diffusion,and then the basic law of water diffusion of asphalt concrete can be obtained.