Dynamically loaded beam failure under corroded conditions

Abstract

De-icing salts, used on roads in heavy winters, may enter reinforced concrete (RC) structures via its capillary pore system or via cracks, initiating reinforcement corrosion and reducing its remaining service-life. Vehicles passing real bridges exert a dynamic impact action that might activate a fatigue failure mechanism. In order to generate more knowledge on the interaction between corrosion and fatigue, a four-point-bending test setup is developed where two lab-scale RC beams are loaded simultaneously. In this setup, RC beams are loaded dynamically, while for one of the beams, corrosion is accelerated by means of a chloridesolution bath mounted on top of it. The second beam, which is the control, is only exposed to tap water. Many test repetitions are foreseen, but so far, three tests are conducted using two different loading levels. It turned out that the reinforcement bar, which corroded due to chloride exposure, failed first in all cases. This paper reports results of the failure mechanism whereby forensic engineering was used to examine the interaction between corrosion and fatigue, and that this might result in a harmful undesirable failure mechanism. The results, therefore, should also be considered for service-life design predictions of infrastructure.