Pore characteristics analysis and numerical seepage simulation of antifreeze permeable concrete

The study of pore structure and seepage flow characteristics can help to reveal the structural and functional performance of permeable concrete from the macroscopic pores. This research aims to investigate the pore structure features and seepage characteristics of fiber-reinforced permeable concrete called antifreeze permeable concrete (AFPC) based on the images obtained by computer tomography (CT) and computed fluid dynamics method (CFD). The results show that the CT scanning and digital image processing technology is an efficient way to analyze the 2D and 3D pore structure of AFPC. 2D planar porosity and 3D connected porosity can generally represent the actual total porosity and connected porosity, respectively. The distribution of 2D Feret diameter and 3D equivalent diameter is in accordance with the normal distribution. The pore structure of AFPC shows fractal features of self-similarity and scale invariance. The fractal dimension shows a linear relationship with 2D planar porosity. CFD method can be applied on the generated 3D connected pore models to reveal the distribution of pressure and velocity in the pores of AFPC during seepage process. The relationship between seepage velocity and pressure gradient is described by Darcy's law and Forchheimer's law and the critical Reynolds numbers for AFPC with different pore structure are obtained. (C) 2020 Elsevier Ltd. All rights reserved.