Structural performance of reinforced concrete beams subjected to combined effects of corrosion and cyclic loading

The deleterious effects of steel rebar corrosion in bridges and viaducts can be potentialized by the cyclic loading to which such structures are naturally exposed. While cyclic loading may lead to progressive bond deterioration and concrete cover cracking, corroded steel rebars may accelerate the fatigue damage accumulation in reinforced concrete elements. Thus, the combined effects of corrosion and fatigue are still more damaging than the disassociated degradation processes. Under this perspective, the experimental program presented in this paper evaluates the synergy between corrosion and fatigue through the load-bearing capacity, vertical displacements at midspan, failure mode, cracking, and fatigue life of corroded reinforced concrete beams submitted to cyclic loading. Corroded reinforced concrete beams (120 × 200 × 1500mm, 2φ12.5 mm, φ 6.3 mm each 100 mm at midspan and 60 mm at shear span) were submitted to 2 million loading cycles (5 Hz) and tested up to failure under a four-point bending scheme. The steel rebar corrosion was accelerated by immersion corrosion testing up to 3–5% (low level) and 8–11% (high level) mass loss. The isolated effects of fatigue and low-level corrosion (3–5%) did not influence the load-bearing capacity and ductility of the reinforced concrete beams, unlike beams submitted to high corrosion levels. The fatigue loading did not influence the load-bearing capacity and ductility of the reinforced concrete beams submitted to low corrosion levels but increased the crack opening, reduced the ultimate load by about 10%, and reduced the ductility of the beams submitted to high corrosion levels. The failure mode changed from ductile to brittle in reinforced concrete beams submitted to high corrosion levels. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.