EXPERIMENTAL STUDY ON BOND STRENGTH BETWEEN CORRODED STEEL BARS AND CONCRETE

Steel bar corrosion is considered one of the main reasons for the limited durability of reinforced concrete. In order to assess the safety of aged concrete structures, it is necessary to determine the bond strength between corroded steel bar and concrete. For this purpose, an experimental study on the bond behaviors was carried out. The parameters investigated include corrosion ratio of steel bar and compressive strength of concrete. Ninety specimens were made for pullout test, each of them was cast as concrete cube with dimension of 100mm, and a steel bar was centrally cast into it. These specimens were partial immerged in chloride solution and the electrolytic method was used to accelerate the corrosion of steel bar. The pullout tests were conducted to determine the bond strength versus slip of steel bar. It is proved that the severe corrosion of steel bar may lead to the splitting cracks of concrete and influence the failure mode of specimen. The damages of specimens are typically in bond splitting. The bond strength between steel bar and concrete rises with the increase of concrete strength, but reduces with the increase of corrosion ratio of steel bar.