Building structures located in saline soil areas are more vulnerable to damage due to the combined effects of loading and sulfate erosion. Polypropylene fibers lithium slag concrete (PFLSC) exhibits good corrosion resistance, which can mitigate damage to building structures in saline soil areas. However, the eccentric compression behavior of PFLSC columns under sulfate erosion and external loading remains unclear. Therefore, in this study, an eccentric compression test was conducted on 10 PFLSC columns after exposure to combined sulfate erosion and external loading, with corrosion time and stress ratio as the research variables. The failure modes, load-displacement curves, failure loads, and strains of rebars were investigated. The results indicate that polypropylene fibers and lithium slag can effectively inhibit the corrosive effects of sulfates and significantly enhance the ductility and ultimate axial capacity of the specimens. Additionally, taking into account the prior load levels and the damage caused by sulfates to the concrete, a damage factor has been introduced to determine the strength of the concrete after undergoing loads and sulfate exposure. Ultimately, a model has been proposed to calculate the ultimate axial capacity of PFLSC columns under the coupled effects of loads and sulfuric acid. The calculated results showed excellent agreement with the corresponding experimental results. It provides reliable guidance for the durability design of PFLSC columns.
