Diffusion of ions through hardened cement pastes

Diffusion of Na+ and Cl− ions through thin hardened paste section was determined as a function of water/cement ratio, curing time, curing temperature, and diffusion temperature. Diffusivities of Na+ ions were smaller than for Cl− ions in the temperature range measured up to 60°C. Activation energies for diffusion were calculated, and contrasts were made with diffusion through a low porosity quartzite rock having minimal surface interaction with the diffusing species.