A computational study of the effect of structural anisotropy of porous asphalt on hydraulic conductivity

The estimation of hydraulic conductivity is important for design and quality assessment of porous asphalt surface courses which directs rain runoff to the drainage system. Structural anisotropy which is induced from compaction may have a strong impact on permeability and flow residence time. Numerical modeling of flow in the pore network is presented based on actual pore geometry reconstructed employing X-ray computer tomography. The results are used to estimate the Darcy’s permeability, Forchheimer resistance and formation of ice in the pores, showing that hydraulic conductivity is highly anisotropic and may vary by a factor of 2 depending on the flow direction.

► Pore geometry of porous asphalt was reconstructed employing computer tomography (CT).
► Flow field was modeled via numerical simulations of pore scale fluid flow.
► Darcy’s permeability, Forchheimer resistance and ice formation were estimated.
► Results show hydraulic conductivity is highly anisotropic and may vary by a factor of 2.