Numerical study on seepage flow in pervious concrete based on 3D CT imaging

Abstract

Pervious concrete specimens are prepared for CT (Computed Tomography) imaging and numerical simulation to observe pore characteristics and study law of seepage flow. 3D reconstruction based on CT imaging is utilized to generate virtual 3D pervious concrete structures, extract the connected pore network models, and analyze the target porosity, actual porosity, 3D porosity etc. Pore characteristics analysis shows the 3D porosity, and average planar porosity can generally represent the actual porosity, and 3D connected porosity is close to the effective porosity. The connected pore network models are used to simulate the water seepage flow using CFD (Computed Fluid Dynamics) method. The seepage flow simulation shows the permeable capacity increases clearly with increasing porosity under the same inlet pressure. The relationship between seepage velocity and pressure gradient is obtained and fitted by the nonlinear Forchheimer formula. The acquired hydraulic conductivity can be used to assess the seepage flow capacity.