• Concrete mixes incorporated 50% GGBS and various EAF slag coarse aggregate ratios • Natural aggregate was replaced by EAF slag at 0–100% by mass • Slump decreased with increasing slag content due to aggregate morphology • Compressive and splitting tensile strengths increased at 7 and 28 days • Water absorption decreased, indicating reduced permeable porosity • SEM analysis revealed a denser ITZ around EAF slag aggregates • Results support the engineering use of slag-based concrete in arid regions Concrete production is associated with significant environmental impacts due to its reliance on Portland cement and natural aggregates. This study reports experimental results on concrete incorporating ground granulated blast furnace slag (GGBS) as a partial cement replacement and electric arc furnace (EAF) steel slag as a coarse aggregate. Concrete mixtures were prepared with 50% GGBS replacing cement by mass, while natural coarse aggregate was replaced with EAF slag at 0%, 30%, 50%, and 100%. All mixtures were produced with constant water-to-binder and aggregate-to-binder ratios to isolate the influence of aggregate substitution. Workability was evaluated using slump tests, while compressive strength, splitting tensile strength, and water absorption were measured at 7 and 28 days. Microstructural characteristics were examined using scanning electron microscopy, focusing on the interfacial transition zone (ITZ) of the control mixture and the mixture with full slag replacement. The incorporation of EAF slag resulted in reduced workability, with slump decreasing by up to approximately 45%, attributed to the angular shape and rough surface texture of the slag particles. Despite this reduction, mixtures containing EAF slag exhibited improved mechanical performance, with increases of up to approximately 32% in 28-day compressive strength and 58% in splitting tensile strength. Water absorption decreased by approximately 20–25% with increasing slag content, indicating a denser concrete matrix. SEM observations showed a more compact ITZ with reduced microcracking and enhanced C–S–H formation. The results provide experimentally validated data supporting the engineering use of GGBS and EAF slag in concrete, particularly for aggregate-scarce regions.
Ali-Ahmad et al. (Sun,) studied this question.