UPSCALING OF PERMEABILITY OF POROUS MATERIALS: FIRST INSIGHT INTO THE EFFECT OF PORE-SPACE CHARACTERISTICS

摘要

The material phase "air" (pore space) in porous materials determines the amount of fluid flow into and through the material and, hence, the time scale of physical/chemical degradation processes in durability aspects of materials and structures. Hereby, the pore-space characteristics, such as pore-size distribution and pore arrangement, both being accessible via respective experimental techniques, influence the transport properties of the material. In this paper, this influence is investigated within the multiscale framework, employing a so-called random pore-network model. Hereby, random arrangements of prescribed pore-size distributions are modeled, giving - under the assumption of steady-state flow conditions - access to the macroscopic permeability of the material. More specifically, three idealized pore-size distributions, i.e., (ⅰ) two different radii and (ⅱ) constant and (ⅲ) normal pore-size distribution, are investigated by means of several sets of network configurations. From the obtained results, both mean value and standard deviation of the macroscopic permeability corresponding to a certain pore-size distribution are determined, giving new insight into the impact of pore-space characteristics on the permeability and its variation in porous materials.