Weerstand van alkalisch geactiveerde Fe-rijke non-ferro-metaalurgie-slak tegen agressieve media

This thesis investigates the durability of alkali-activated Fe-rich non-ferrous slag (AA-NFS) as a sustainable alternative to traditional cement in aggressive environments. Given that cement production is responsible for 8% of global CO₂ emissions, alkali-activated materials (AAMs) derived from industrial by-products like NFS present an environmentally viable option. The research focused on understanding how variations in NFS chemical composition impact AA-NFS properties, including strength and porosity, and its resistance to sulfate salts (Na₂SO₄ and MgSO₄), sulfuric acid (H₂SO₄), and acetic acid (CH₃COOH). Higher Al/Si ratios in the slag increased reactivity and compressive strength, while higher Ca/Si ratios enhanced long-term strength. AA-NFS demonstrated robust resistance to sulfate environments, where a protective Mg(OH)₂ layer forms under MgSO₄ exposure, impeding further attack. In sulfuric acid, AA-NFS degrades severally and forms gypsum, which can partially protect against corrosion but can also lead to degradation if present in excess. Acetic acid exposure resulted in a more polymerized network within AA-NFS, and an enhanced resistance can be achieved in a less permeable system. The study identifies the optimal slag compositions for each environment, indicating that compositions high in Al and medium in Ca (~10 wt% CaO) perform best in acid-rich settings. These insights highlight AA-NFS's potential in marine and agricultural structures and inform strategies for composition tailoring to enhance performance. The findings advance understanding of Fe-rich slag-based binders and set the stage for future research into optimizing AA-NFS for real-world applications.