Analysis of rust-jacking cracking of concrete cover under non-uniform corrosion of reinforcing bars

At present, the analyses of rust-jacking cracking of reinforced concrete components are mostly obtained based on accelerated tests, and the rust-jacking cracking models are mostly derived from uniform corrosion However, this approach exhibits certain discrepancies when compared to the actual crack propagation observed in corroded reinforced concrete components in real-world environment, thereby affecting the accuracy of cracking time predictions. Based on the theory of elastic mechanics, this paper established a mechanical model of non-uniform rust-jacking cracking of reinforcing bars. This model established the relationship between the corrosion rate of reinforcing bars and parameters, including the non-uniform corrosion morphology, expansion coefficient of rust products, elastic modulus of rust products, thickness of the concrete cover, concrete elastic modulus, and the diameter of reinforcing bars. Using marine environmental exposure tests as the research object, the cracking behavior of concrete under real environmental conditions was analyzed. The accuracy of the proposed mechanical model and the sensitivity of key rust expansion cracking parameters were evaluated through numerical simulation methods. The results indicated that the volume expansion coefficient and the elastic modulus of rust products significantly influence both the width and initiation time of rust-jacking cracking. Accordingly, recommended value ranges for these two key parameters under marine environmental conditions were provided..