Influence of corrosion on the structural stiffness of reinforced concrete beams

This work presents an experimental investigation that correlates the stiffness changes of reinforced concrete beams with the amount of steel cross section loss and concrete cover-cracking morphology due to localized corrosion of the embedded steel. Ten concrete beams (100 by 150 by 1,500 mm) with the central portion contaminated by chlorides placed during mixing of the concrete were used in this investigation. In addition, two beams without chloride contamination were used as controls. Corrosion was further accelerated in the chloride-contaminated beams by impressing an anodic current to the single no. 3 steel reinforcement bar (10 nun diameter). During corrosion acceleration, the beams were tested under flexure by a cyclic loading-unloading procedure. The changes on the stiffness (slope of the force-displacement diagram) and crack morphology of the concrete cover were recorded periodically while the specimens were corroded. The results obtained showed a decrease in the flexure stiffness as much as 32% for a 14% reduction in the rebar radius.