Coefficient of Oxygen Permeability and Diffusion of OPC and Fly Ash Blended Concrete: Effects of Porosity and Degree of Saturation

Measurement of the coefficient of gas permeability and diffusion (such as oxygen) of concrete has been recognized as the important criteria to estimate the durability and the performance of concrete. Although there are many factors that control the flowing of gases through pore network of concrete, porosity and moisture conditioning are the most significant among them. Permeability to gases in concrete is inversely related to the degree of saturation of concrete; in completely saturated concrete (100% degree of saturation), permeability to gases cannot be measured, whereas maximum permeability is measured at perfectly dry (over dried) samples. In this investigation, coefficients of oxygen permeability and diffusion of OPC and fly ash blended cement concrete bearing different degree of saturation were measured. The total porosity of concrete was also measured. The total porosity and the degree of saturation of concrete, which is defined as the open porosity had significant effects on the coefficient of oxygen permeability ad diffusion and the valid statistical correlations were obtained.