The seepage flow state characteristics of SMA-13 asphalt mixture under triaxial fatigue load

Abstract The seepage flow state of water in asphalt pavement may not accordant with Darcy law due to the high hydrodynamic pressure generated under high-speed traffic load, In order to study the seepage flow state of water in asphalt pavement under high water pressure conditions and analyze the critical conditions for non Darcy flow to occur, the SMA-13 asphalt mixture with different compaction methods and different percent air voids were prepared, and triaxial fatigue tests and high water pressure seepage tests were conducted on the specimens, hydraulic gradient and critical Reynolds number were used to distinguish Darcy and non Darcy phenomena in the seepage process. The results indicate that the linear flow occurs at low flow velocity in the SMA-13 asphalt mixture with different compaction methods and different percent air voids, it shows obvious nonlinear flow at high flow velocity. The values of linear component coefficient a and nonlinear component coefficient b obtained by nonlinear fitting by using Forchheimer’s law decrease with the increase of percent air voids, and the values of the coefficients of specimens formed by rotary compaction molding are larger than those formed by Marshall compaction molding. The critical flow velocity and critical Reynolds number increase with the increase of percent air voids before and after triaxial fatigue loading with different molding methods.