A New Theoretical Model Study on the Cover Cracking Mechanism of RC Structures Due to Rebar Corrosion

Based on elastoplastic and damage mechanics theory, a new theoretical model of damage cracking on the cover of reinforced concrete structures caused by non-uniform rust expansion is established. The parameter sensitivity analysis indicates that the critical corrosion rate of the structure increases sharply with the increase of the thickness of the concrete cover. The critical corrosion rate decreases when the non-uniform coefficient of the corrosion expansion becomes larger, indicating that the uneven corrosion expansion is disadvantageous for durability. When the rust expands more unevenly, the allowable corrosion amount of the reinforcement becomes smaller. While the concrete grade changes from C15 to C60(concrete design standard in China), the critical corrosion rate modifies between 3.05 parts per thousand and 4.1 parts per thousand. To further verify the rationality of the new theoretical model, the model was conducted to predict the standard corrosion tests. Results show that the scatter points predicted by the new model are small-amplitude oscillation near the test line. Thus, it has been proved the new theoretical model proposed in this paper can be used to predict the critical corrosion rate of RC structures.