Corrosion behavior and flexural performance of reinforced concrete/ultrahigh toughness cementitious composite (RC/UHTCC) beams under sustained loading and shrinkage cracking

This paper presents an experimental study of the corrosion behavior of reinforced concrete/ultrahigh toughness cementitious composite (RC/UHTCC) beams under simultaneous loading and shrinkage cracking, and of the flexural performance of these beams after corrosion. During corrosion, a two-stage corrosion test was applied - wet/dry cycles of chloride solution first and then accelerated corrosion using impressed current. Corrosion potential in the first corrosion stage and corrosion electrical resistance and corrosion pattern in the accelerated corrosion stage were measured, and rebar corrosion appearance was observed after bending tests. The results indicated that the corrosion potential decreased rapidly after exposure to chloride solution while the corrosion electrical resistance increased with corrosion time. No corrosion-induced longitudinal cracks occurred at corrosion levels up to 16.32%, but severe pitting corrosion of reinforcement was observed at transverse cracks. The load-carrying capacity, deformation, ductility, and flexural crack pattern of corroded RC/UHTCC beams were degraded greatly due to pitting corrosion effect. Ductile concrete crushing failure mode was transformed to brittle rebar rupture failure mode. The sustained loading action further aggravated the degradation in flexural capacity of corroded RC/UHTCC beams. (C) 2018 Elsevier Ltd. All rights reserved.