Response of Reinforced Concrete Beams under the Combined Effect of Cyclic Loading and Carbonation.

To compare the deterioration mechanism of reinforced concrete beams between the combined effect of cyclic loading and carbonation and the sum of both individual factors, an optimized test procedure was introduced in this study. The macroscopic and microscopic results showed that the decrease in carbonation resistance of concrete could be attributed to the changes in pore structures and crack patterns introduced by cyclic loading. However, the carbonation process of flexural tensile concrete corresponding to different test procedures presented different trends. It indicated that the combined action of carbonation and fatigue damage was more serious than the damage caused by the effect of superposition. Finally, a theoretical carbonation model of concrete subjected to the combined damage was proposed and validated by comparing it with previous experimental results. The research findings are significant for improving the accuracy of evaluation of residual service life of reinforced concrete bridges and early warning of durability protection. [ABSTRACT FROM AUTHOR]