Corrosion-induced cracking of reinforced-concrete (RC) covers is well known, yet key knowledge gaps persist. Most studies isolate uniform corrosion or a single non-uniform corrosion pattern and ignore the effects of boundary restraint and structural configurations, leading to inaccurate predictions of cracking thresholds and crack propagation patterns. This study systematically investigates the influence mechanisms of constraint conditions and structural configurations on corrosion-induced cracking behavior using the phase-field model. The results indicate that the non-uniformity of steel corrosion is a critical factor governing cover cracking. As the corrosion non-uniformity coefficient increases, the critical corrosion level exhibits a monotonic decreasing trend—from 0.95% to 0.15% under strong constraints and from 0.52% to 0.15% under weak constraints. Concurrently, the crack morphology evolves from a single radial crack to a wedge-shaped crack oriented toward the peak corrosion side. The influence of constraint conditions is dualistic, while strong constraints enhance the failure threshold, their mitigating effect diminishes markedly under highly non-uniform corrosion. The critical corrosion threshold for eccentrically arranged corner reinforcement is significantly lower than that for centrally arranged reinforcement; the corrosion angle only induces slight crack deflection and minor threshold fluctuations; and the curved top section, due to its weaker equivalent constraint, exhibits inferior crack resistance compared to the linear top section. Three-dimensional analysis reveals a pronounced longitudinal discreteness effect, which not only substantially elevates the critical corrosion threshold but also leads to diverse spatial failure modes. This work links rust-expansion eigen-displacement to crack propagation within a unified phase-field framework, providing materials-level criteria for evaluating corrosion tolerance and guiding the design of cover materials and reinforcement layouts to enhance durability.

Temperature-induced cracks during the construction of large concrete structures, such as water gates and bridges, caused by hydration heat, pose a serious threat to structural safety and reliability. To address this, various countries have developed temperature control standards and guidelines for mass concrete structures, providing design direction and evaluation criteria. China and the United States (U.S.) are leaders in the field of temperature control for mass concrete structures, with significant influence in international projects. The study of the differences in temperature control results between the two countries’ standards not only helps to understand the impact of different regulations on temperature control design but also provides more design options for multinational projects. This study uses ABAQUS software (version 2023)to establish a finite element model of a water gate and employs secondary development of ABAQUS to simulate the temperature and stress fields under both Chinese and U.S. standards. The results indicate that the overall temperature and stress distributions of the structure are similar under both standards. The calculation results for internal and surface characteristic points show that the maximum temperature predicted by the Chinese standard is slightly higher than that of the U.S. standard, with a difference of no more than 1.7 °C. However, the maximum tensile stress calculated under the Chinese standard is lower than that of the U.S. standard, with internal stress differences not exceeding 0.23 MPa and surface stress differences not exceeding 0.56 MPa. This study provides a direct comparison of the temperature control results between the two standards, offering valuable insights for international projects to balance cost and safety, while also providing empirical evidence for optimizing national standards.