Study On The Influencing Factors Of The Permeability Of Asphalt Pavements

With the rapid development of economy and society in our country, the high-way construction also goes into a rapid developing term. However, during this process, the high-way in China has been this or that disease, which is the most typical of early damage in the asphalt pavements. Research shows that the early damage relates to the effects of water in the asphalt pavements. It mainly causes by water seepage of the asphalt pavements. The important standard that weighs the quality of good or bad in the pavements is the permeability of asphalt pavements.According to the research status of the permeability of asphalt pavements in our country, this paper has analyzed the situation of water seepage in the different asphalt pavements. Based on the Marshall test and the water seepage test, each factor of influencing the permeability of asphalt pavements is deeply and systematically studied, the permeability of asphalt pavements and its variation are explored in order to maximize present and reduce the water damage causes by the permeability of asphalt pavements. Permeability coefficient is an intuitive index for reflecting the permeability of asphalt pavements. It reflects the speed of water in the internal surface layer structure and its porosity and the connectivity. It has many influencing factors, such as the nature of asphalt raw materials, mineral aggregate gradation and air voids and so on.This article has analyzed each factor of the water seepage in the asphalt pavements by used of the grey relation degree analysis method. The research shows that the grey relation degree theory can be used to analyze the factors'influence to the asphalt pavements seepage and it can fit well with all kinds of factors. The result of the grey relation degree theory has shown that air voids is the most principal influence factor to the water seepage of the asphalt pavements; The penetration of asphalt is an important influenced factor to the water seepage of asphalt pavements; The voids in mineral aggregate reflects the degree of close in some certain experimental conditions and decides the volume of the asphalt so that influence to the voids and saturation. It relates to the mineral gradation, whetstone ratio and powder-binder ratio, so it plays an important role for the water seepage of asphalt pavements.According to the permeability of the single asphalt pavements, the permeability of the entire pavements can be calculated on the basis of the principle of the superimposition in the water seepage.