Test Research On The Ability Of Protecting Reinforce Rebar From Corrosion In Concrete In Chloride Environments

Corrosion of the rebar in concrete is one of the key factors that affecting the security anddurability of the reinforced concrete structures. The protection of the concrete to the rebar isdecided on the ability of protecting reinforced rebar from corrosion. The half-cell potential is animportant parameter of the corrosion stage.In this paper, the environment of cyclic wet and dry and chloride induced is simulated,and the potential of the rebar in different kinds of concrete is measured in order to compare theability of protecting rebar from corrosion. Specimens of nine kinds of concrete are cast andplaced in cyclic chloride penetration environments, and the potential is measured after certainintervals. The surface condition of the concrete specimen is observed simultaneously to recordthe cracks and the stain of the corrosion products. Finally, the curves of the potential vs. timeare used to evaluate the ability of protecting reinforce rebar from corrosion. The results indicatethat: the ability of protecting reinforced rebar from corrosion is increase with the compressivestrength and decrease with the water/cement ratio. According to the Portland cement concrete,the concretes containing admixtures perform well, while the concrete containing silica fumeand fly ash has a lower permeability and the best ability of protecting the rebar from corrosion.And the steel fiber reinforced concrete performs well in protecting the rebar against corrosion,while the carbon fiber is useless in controlling cracking and improving the permeability of theconcrete.The characters of the concrete are detected, and the Scanning Electron Microscope is usedto analysis the microstructures of the concrete to find out the cause of the differences in theability of protecting reinforced rebar from corrosion.The feasibility of the method of half-cell potential associating with the linear polarization isstudied, and it can help to improve the wok efficiency.This paper gives the guidance of confect the concrete of high durability in chloride inducedenvironments and the reference for detecting the corrosion of the rebar in concrete using Canin.