Experimentally Measured Permeability of Uncracked and Cracked Concrete Components

Abstract

In this paper, the relationship between concrete damage and air flow is evaluated using model-scale reinforced concrete walls. The focus is on the walls behavior under uniaxial and biaxial loading conditions. The method for evaluating the damage-flow rate relationship includes structural testing of scaled specimens, damage identification, and air flow rate experiments. Concrete damage is characterized on a local and global level, via consideration of crack characteristics (length and width) and drift ratio, respectively. Nine model uniaxial specimens and 13 model biaxial specimens were tested, with variations in geometry, material, and loading details. All specimens had a well-defined region of interest for damage identification and air flow testing. Air flow tests, in the form of pressure decay tests, were used to measure the permeability of the concrete at different loading stages. Results indicate that the largest cracked concrete permeability occurs in specimens with low concrete strength, low reinforcement ratio, higher cycle count loading protocols, low axial load, and low aspect ratio. In contrast, the lowest cracked concrete permeability values are associated with high strength concrete, high reinforcement ratio, and high axial load.