Mechanical and durability performance under freeze–thaw cycles for fiber-reinforced 3D-printed cement mortar containing electric arc furnace dust

The global production of Electric Arc Furnace Dust (EAFD) presents significant environmental challenges due to its hazardous composition and disposal issues. This study investigates the mechanical behavior of cement mortar incorporating EAFD as a partial cement replacement under freeze-thaw (F-T) cycles. The research focuses on evaluating the effects of varying EAFD content (0%, 5%, 10%, and 15%), fiber reinforcement, and water-to-binder ratios (0.3 and 0.35) on the compressive and flexural strength, durability, and porosity of 3D-printed slag concrete (3DSC). The findings reveal that EAFD replacement up to 10% improves freeze-thaw resistance while higher replacement levels (15%) significantly reduce mechanical strength and increase porosity. Fiber reinforcement enhances structural integrity but exhibits diminishing returns at higher EAFD contents. A lower water-to-binder (W/B) ratio (0.3) generally improves strength retention, while a higher ratio (0.35) accelerates deterioration over extended F-T cycles. The study identifies an optimal balance of EAFD and fiber content for sustainable concrete applications, contributing to circular economy principles by repurposing hazardous waste in construction.