The seepage path of water through porous composite airport pavement is longer than the length of the seepage path through porous pavement. To enable proper drainage, porous composite airport pavement must have rational structure design. In this paper, multiple seepage models were established through porous asphalt concrete layers with different drainage structures. Based on these models, an equation was developed through the mechanics of fluid flow. This equation was found the depth of the water table flowing through the porous asphalt layer. The maximum depth (Hmax) was solved numerically using the fourth order Runge-Kutta method. According to the regression analysis of the numerical solution, a formula for calculating the maximum length (Lmax) of the seepage path to avoid the surface runoff was found. Based on the formula, under different rainfall intensity, a nomogram on the relationship among seepage length, inclination and air void of porous asphalt, was given. The formula and nomogram can be used to guide structural design of porous composite airport pavement.
Abstract