Test on bond behavior between non-uniform corroded steel and concrete

Abstract:

Eight beams of reinforced concrete were prepared to investigate the deterioration law of non-uniform corrosion on the bond performance of steel bar and concrete. First, the corrosion of the steel bar was obtained by applied-current. The electricity was stopped when the specimen reached the designed mass loss rate, and the development of corrosive cracks on the concrete surface was recorded. Then, three-point bending load was applied to the beam specimen to test its bonding performance. Finally, the corroded steel bar in the bonding area was taken out for 3D scanning test after the bond failure of the beam specimen. Test results show that the volume expansion of the corrosion products of the steel bar caused the corrosive cracks in the concrete protective layer along the axis of the longitudinal tensile bar, and the maximum corrosive crack widths on the concrete surface had a logarithmic relationship with the mass loss rate of the steel bar. There were rust pits on the surface of the corroded steel bar, and as the mass loss rate of steel bar increased to 10.3%, the total length, width, and depth of the rust pits increased by 68.7,0.21, and 9.98 mm, respectively, suggesting that the total length of the rust pits had the most significant increase. On the basis of the test results, a relative bond strength degradation model of steel bar and concrete was established in consideration of the influence of non-uniform corrosion. According to the correlation between the mass loss rate and the maximum corrosive crack width on the concrete surface, a calculation model of relative bond strength based on the maximum corrosive crack width on the concrete surface was proposed and verified.