Study of Concrete Deterioration Damage by Landfill Leachate in Cold Regions

The corrosion mechanism of concrete structures in landfills in cold regions is complex, and there are few existing studies that address multifactorial coupled deterioration scenarios. Since loading and freeze-thaw cycles affect concrete deterioration, this study included three test groups-landfill leachate, loaded-landfill leachate, and freeze-thaw cycles-loaded-landfill leachate-and three different corrosion scenarios-gas-liquid, liquid-solid, and gas-liquid-solid. The physico-mechanical changes in concrete in terms of mass, compressive strength, and dynamic elasticity modulus were analyzed, and the deterioration mechanism of concrete was elaborated by its apparent morphology and scanning electron microscope (SEM) images. The study showed that the most serious damage to concrete was caused by freeze-thaw cycles, loading, and landfill leachate coupled in multifactorial situations. The compressive strength and dynamic elastic modulus decreased; the endpoints decreased by 15.75% and 7.42%, respectively, and increased by 12.51% and 6.74% compared with the unapplied load group. The concrete in the gas-liquid-solid test group had the most serious damage among the corrosion scenarios, with a 21.63% decrease in compressive strength. This study determined the most unfavorable corrosion conditions for concrete structures in landfills in cold regions and the corrosion mechanism of concrete exposed to landfill leachate and provides a technical reference for the construction of landfill facilities.