Toward Zero-Carbon Concrete: Alkali Activation of Ladle Furnace Slag Using Cement Kiln Dust

This study investigates the potential of producing zero-clinker, alkali-activated binders and concrete entirely from industrial by-products—ladle furnace slag (LFS), coal ash (CA), and cement kiln dust (CKD). The incorporation of CKD enhanced the workability and compressive strength properties of the alkali-activated mixtures, with the highest mechanical properties at 20% CKD addition. XRD, FTIR, and SEM analyses confirmed the formation of hydrocalumite, indicating improved hydration and microstructural densification. Mortar and concrete produced using the eco-cement reached 28-day strengths of 34.5 MPa and 32.6 MPa, corresponding to concrete class C20/25. These findings demonstrate the feasibility of manufacturing 100% waste-based construction materials suitable for sustainable, non-reinforced applications.