Research of the Influence of Concrete Designed Value to Corrosion of the Steel Bar under Chloride Environment

The influence of designed parameters including W/B ratio,composition of binding materials,depth of concrete cover and chloride ion content in concrete on corrosion of the steel bar in concrete was studied.Simulation tests are made in chloride environment,by accelerating the corrosive rate of the steel bar in concrete specimen.Electrochemical method(half-cell potential and corrosion current density) are used to evaluate the experimental result.It is found that to decrease the W/B ratio,increase the depth of concrete cover,lower the chloride ion content in concrete and use mineral binding materials,the initiation time of steel bar corrosion in concrete can be delayed and the corrosion rate can be decreased to certain extent.Concrete specimen are crashed during the experiment and the mortar beside the steel bar are taken out to make samples for SEM testing to venify the rationality of electrochemical method and the real corrosion extent.