Effect of W/C and Thickness to Corrosion Properties of Reinforced Concrete

摘要

Reinforced concrete structures have increased in number due to the rapid development of industrial society. In addition, these reinforced concretes are often exposed to severe corrosive environments such as sea water, contaminated water, acid rain and seashore etc. Thus, corrosion problems of the inner steel bar embedded in concrete are very important from a safety and economic point of view. In this study, the effects of cover thickness and W/C ratio(water to cement ratio) on corrosion properties of reinforced concrete were investigated with electrochemical methods such as corrosion potentials, polarization curves, cyclic voltammograms, oxygen diffusion limiting current densities and oxygen diffusion coefficient measurements, etc. Corrosion potentials shifted to the noble direction with increasing cover thickness. Oxygen diffusion limiting current densities decreased with increasing cover thickness. However, oxygen diffusion coefficients showed a relatively increasing trend regardless of w/c ratio with increasing cover thickness. Furthermore, it appeared that diffusion coefficients decreased with increasing w/c ratios for the same cover thickness. Resistance polarization is nearly controlled by the cover thickness in sea water solutions, however the effect of cover thickness was observed to be smaller with increasing w/c ratios.