Research On Moisture Damage Of Asphalt Pavement ——about Factor Of Pore Water Pressure

Road is one kind of absolute establishment for intercourse between zones, establishing perfect traffic system construction is the first task to expedite development. For these years, government increased invest in economic development, with this reason traffic establishment showed more and more important function . With the development of economy, demands of road capability become more and more well. Asphalt pavement is used abroad because of it's superiorities, for example travelling comfort, little noises, traffic opening quickly, speciosity and so on. In the processor of adhibition, road appeared many kinds of damage .Almost of these damage hanppened in the early days .,called forepart damage (ex.moisture damage).Appearing of damage decreasing service capability of road ,cutting the using life of the road ,increasing the expenses in conserving and maintaining.This paper adopted the finite element theoretics recured to analyse software- ANSYS , established road layers model , analyzed mechanics effect of pavement structure ,based on these analysis discussed the connection between pore pressure and correlative factors ,that the pore locate between two layers. When increasing the thickness of asphalt layers and base , this measure can decrease the displacement and stress on the nodes of the structure ,but the pull stress on the nodes which located based bottom are increased ,the rule is not simple linear connection. Increase asphalt layer is more significative than that of base layer, it's decrease ratio is much greater, also the pull stress increase ratio with in base layer is smaller than the result of increase base layer thickness. Another measure of decrease stress and displacement is about modulus of layers. With the increase of modulus, appeared the minimum stress, in order to get the balance between increase and decrease, we can acquire better results from adjusting modulus of first layer. In the faction of controlling pore pressure, adjusting thickness of base layer is more superior. When the thickness of this layer is changed, the transformation of pore pressure like parabola have descending phase, that is a good measure to decrease pore pressure .when the wheel loads become, the increase ratios of pore pressure in every direction are equal. So it is harmful to the pressure we'd better to avoid the phenomenon of over loading.Based on the analytical results discussed choosing logical thickness and material of structure layers, summing the measure of decreasing moisture damage. In the design phase, we should consider synthetically to choosing thickness of layers and kinds of material , that is important for the performance in the anaphase. Otherwise, bringing some measure of decreasing moisture damage forward based on construction process. For example, established perfect drainage system, controlled quality strictly, that include maintain in anaphase should be perfected, do this is in order to decrease the happening of moisture damage and losing of it.