Experimental survey on corroded reinforced concrete and prestressed concrete beams

Steel reinforcement corrosion represents one of the major degradation causes of reinforced concrete and prestressed concrete structures. The paper presents and discusses the outcomes of a wide experimental survey, carried out at the University of Rome “Tor Vergata” on both types of elements, for the evaluation of their flexural response when subjected to corrosion. The experimental campaign, including seven reinforced concrete and six prestressed concrete beams tested in four-point bending, was subdivided in two groups. A first group of beams was tested at the end of an artificial corrosion process, provided to obtain different damage levels. A second group of beams was tested with a more realistic procedure, consisting in a simultaneous application of loading and artificial corrosion. All the beams featured a length of 3700 mm and a 200 mm x 300 mm section. Particular care was devoted to the calibration of the corrosion process, to the assessment of the morphology of the corroded steel rebars and strands, and to the interpretation of the results of traditional (potentiometer and linear variable displacement transducers) and innovative measure devices and sensors (MEMS accelerometers, MEMS clinometers and stress sensors). The paper shows the potential consequences of steel corrosion in terms of variation of ultimate strength, displacement capacity and failure mode, that can turn from ductile to brittle. Furthermore, the experimental outcomes highlight the importance to account for the combined effect of reinforcement corrosion and loading and for morphological aspects of the corrosion phenomenon, when assessing the structural performance of corroded elements.