Study on the permeability characteristics of foamed concrete using a pore-scale model from x-ray microcomputed tomography image reconstruction and numerical simulation

Foamed concrete has attracted increasing attention in civil engineering due to its unique properties. Permeability is one of the significant material properties that governs its long-term durability. This work presents a method to explore the permeability characteristics of foamed concrete based on X-ray microcomputed tomography (micro-CT) image reconstruction technique and Simpleware version M-2017.06 software. The pressure and water flow distributions in foamed concrete were obtained, and the permeability of the foamed concrete with different densities was calculated. The numerical simulation results showed that the proposed method can be used to predict the permeability of foamed concrete. The main factors that affect the permeability of foamed concrete are discussed. A power law model is established to reveal the relationship between the porosity and permeability of the foamed concrete, and the connectivity of pores was labeled to explain why the permeability of three different location calculation models are not the same under the same density conditions. Furthermore, the influence of boundary conditions on the calculation results of the permeability was analyzed, and a comparison of the 2D and 3D results were carried out to determine whether it is necessary to reconstruct the 2D CT images into 3D pore-scale physical models.