Effects of Corrosion on Reinforced Concrete Structures

Development of reinforced concrete (RC) structures is quite recent; nonetheless world heritage now includes many RC constructions. Safeguarding the historic value of such structures requires a clear knowledge on predictability of degradation consequences. Among many potential degradation sources, corrosion process of steel bars in RC structures is a structural problem, not simply aesthetical, affecting existing structures and leading to a loss of structural capacity. Because of the volumetric expansion of oxides of steel, the corrosion process, as well as responsible a loss of cross section of reinforcement, leads to concrete cover cracking. The main structural consequences are the reduction of bond between steel and concrete plus the loss of load bearing capacity. In order to determinate the loss of load bearing capacity due to corrosion, theoretical analyses have been performed in order to evaluate steel and concrete degradation, and compared to available experimental outcomes on columns. Under axial loads the loss of load bearing capacity can be associated to a degree of eccentricity due to concrete cover spalling, yielding to even worse consequences. A further theoretical evaluation has been performed to evaluate the loss of load bearing and shear capacity of beams and slabs.