Durability and damage mechanisms of electrolytic manganese residue-based grouting materials for seepage prevention in solid waste landfills under simulated service environments

The durability of impermeable grouting materials in actual environment is crucial for the sustainable engineering application. This study investigates the performance evolution and degradation mechanisms of electrolytic manganese residue (EMR) based grouting materials subjected to wet-dry cycles in three distinct environments: pure water (PW), karst groundwater (KG), and EMR leachate (EL). Results demonstrate that material durability is significantly influenced by both environmental exposure conditions and compositional characteristics. Each environment induced specific structural deterioration mechanisms: alkaline matter dissolution with framework damage in PW, calcium carbonate accumulation in KG, and sulfate attack in EL. During the 12 wet-dry cycles, the KG environment primarily affected compressive strength, while PW conditions most severely impacted hydraulic conductivity. The incorporation of EMR enhanced the formation of gel-state C-(A)-S-H substances, effectively mitigating environmental erosion of the structural framework. Notably, the addition of 30 % EMR effectively constrained the hydraulic conductivity deterioration from two orders of magnitude to within a single order of magnitude compared to EMR-free formulations. This study demonstrates the importance of simulating realistic environmental conditions when evaluating material durability, providing valuable insights for understanding damage mechanisms and enhancing the long-term performances of impermeable barriers in complex service environments.