Durability of cast-in-place (CIP) pile in landfill leachate environment: corrosion behavior and structural integrity assessment

The durability of underground cast-in-place (CIP) piles is frequently overlooked, particularly in construction projects on repurposed landfill sites, where foundations are exposed to aggressive soil leachates containing chloride and sulfate ions. This study investigated the long-term durability of CIP pile exposed to landfill leachate, using leachate collected from an operational landfill site along China's eastern coast. Accelerated corrosion tests were conducted to simulate degradation over a 50-year service life. The results revealed pronounced cracking in the concrete, localized corrosion at fracture zones, and an increase in chloride ion concentration within the concrete matrix, reaching 0.198 wt%. Both the concrete and steel reinforcement exhibited substantial deterioration in mechanical properties. Finite element analysis demonstrated that the safety margin of the concrete was only 0.1 MPa. These findings highlight the necessity of proactive durability design and mitigation strategies for infrastructure built on contaminated urban land.