Effect of uniaxial compressive loading on gas permeability and chloride diffusion coefficient of concrete and their relationship

Knowledge of the transport properties of damaged concrete in marine environments is essential for predicting its durability. The objective of this study was to fill this gap by correlating the change in permeability and chloride diffusivity with an increasing uniaxial load on ordinary concrete (OC) and high performance concrete (HPC). Concrete cylinders were induced microcracks by mechanical uniaxial compression between 60% and 90% of the ultimate strength to get diffuse damage. The damage variable of specimens was evaluated by elastic stiffness degradation and ultrasound pulse velocity. After unloading intrinsic gas permeability was measured using a constant head permeameter, the chloride migration coefficient was evaluated by migration test in steady state conditions, with the same concrete specimen. The damage variable of specimens showed relationship with gas permeability and chloride diffusion of concrete in this experiment. A correlation was obtained between intrinsic permeability coefficient and chloride diffusion coefficient depending on the damage variable, specific for each concrete type (OC and HPC).