Full-Scale Experimental Investigation on Mechanical Degradation and Failure Mechanisms of Reinforced Concrete Pipes under Sulfuric Acid Corrosion

Drainage infrastructure, particularly reinforced concrete pipes, faces significant degradation due to microbially induced concrete corrosion in sulfuric acid environments, leading to substantial economic and safety concerns. However, existing research predominantly relies on small-scale specimens, and current failure prediction models for full-scale pipes lack comprehensive experimental validation, thereby hindering accurate service life prediction and the development of practical design guidelines. This study addresses these critical gaps by conducting full-scale experimental investigations into the mechanical performance and deformation characteristics of reinforced concrete pipes exposed to a 5% sulfuric acid environment over durations of 0, 30, 60, and 90 days. Utilizing a specialized sulfuric acid corrosion setup and a three-edge bearing test system, our findings reveal that sulfuric acid corrosion induces significant phase-dependent and nonlinear changes in pipe performance. We observe a complex evolution of crack development, transitioning from initial uniform circumferential cracking to a coexistence of mixed and longitudinal cracks, ultimately forming an interconnected network. Crucially, the failure mode shifts from being dominated by structural integrity to material degradation, with the inner ring deteriorating more rapidly. Pearson correlation analysis further demonstrates a strong positive relationship between elliptical deformation and load-bearing capacity, reflecting a significant weakening of pipe stiffness and durability. By employing full-scale experiments and simulating realistic corrosion conditions, this research provides a robust reference for the reliability assessment and service life prediction of concrete pipe structures in sulfuric acid environments, offering valuable insights for engineering design optimization and maintenance strategies. Crucially, these findings offer a direct scientific basis for calibrating predictive models and enhancing the practical engineering standards used in pipeline design and maintenance.