Behaviour of reinforced cement concrete under coupled corrosion fatigue

This study has investigated the synergistic effects of corrosion and fatigue on lightly re- inforced concrete (RCC) structures, with a focus on understanding the coupled deterioration mech- anisms in real-world conditions. Concrete beams have been subjected to constant amplitude fatigue loading while submerged in a saline solution to simulate accelerated corrosion. The corrosion kinet- ics parameters, including corrosion current density (icorr), half-cell potential, and concrete resistivity, have been continuously monitored using a linear polarization resistance (LPR) device during fatigue loading. The study has employed a novel two-beam setup to compare the fatigue life and corrosion rate under coupled loading and staggered loading conditions. The results have demonstrated a sig- nificant increase in corrosion current density under fatigue loading compared to control specimens subjected to corrosion alone, highlighting the accelerated degradation due to the combined effects of corrosion and cyclic loading. Pitting corrosion has been found to dominate at the intersection of cracks and the reinforcement bars, with corrosion pits acting as fatigue crack nucleation sites. The study has revealed a clear correlation between corrosion progression and fatigue life, with the cou- pled corrosion and fatigue loading causing more severe damage and reducing the fatigue life of RCC beamscomparedtostaggeredloadingconditions. This research has provided critical insights into the coupled corrosion fatigue mechanisms in lightly reinforced concrete flexural members, offering valu- able information for understanding the long-term durability and safety of RCC structures subjected to both environmental and loading conditions. The findings have also contributed to the development of better predictive models for the performance and lifespan of concrete infrastructure exposed to aggressive environments.