This study aimed to evaluate the long-term service performance of modified municipal dewatered sludge as a landfill liner barrier. Industrial calcium-containing solid waste was used as a modified material for sludge. The shear strength parameters (cohesion c, friction angle φ), compressive strength, and hydraulic conductivity of the modified sludge were studied using direct shear, uniaxial compression, and penetration tests. The leaching toxicity, hydration products, and microscopic morphology of the modified sludge were determined using atomi...