Study on Sectional Nonuniform Corrosion and Bond Strength of Plain Rebar Embedded in Concrete

The assessment of nonuniform corrosion of rebar is a key issue concerning the reliability of reinforced concrete structures. In this paper, the sectional nonuniform corrosion of plain rebar and the effect of corrosion on bond strength with concrete are studied. The plain rebar in concrete of 52 specimens were fast corroded by using electrochemistry method in a 5% sodium chloride solution. The bond strength of corroded plain rebar in concrete was measured by the central pull-out test. The sectional contour, diameter loss and sectional area loss of corroded plain rebar were detected within the bond length corresponding to the mass loss from 0.1 % to 11.9%. Based on the oretical analysis and test data, the predictive models of the corroded sectional contour line and the bond strength of corroded plain rebar to concrete are built up. The results indicate that the nonuniform corroded sectional contour of plain rebar is approximate elliptical shape, the bond strength can be predicted by using the diameter loss of corroded rebar. Finally, the adaptability of the predictive models is ascertained with the experimental results.