Oxygen availability in the corrosion of reinforcements

Abstract

The rate of steel corrosion in concrete structures is believed to be mainly controlled by the diffusion of dissolved oxygen through the concrete cover. Different techniques have been employed to measure the diffusion rate of this gas: either utilizing mechanical driving forces, natural diffusion or electrochemical forces. The Paper discusses results of oxygen flow through paste, mortar and concrete without admixtures, related to rebar corrosion and concrete resistivity. The results give information on the reliability of cathodic polarization to detect the O2 availability at the rebar surface, and confirm that the controlling variable is the humidity content in pores, which also influences the corrosion rate.