Revisiting Iron Slag as Coarse Aggregate in Concrete: A Systematic Review of Mechanical Performance, Durability, and Sustainability

Abstract— This study entitled Revisiting Iron Slag as Coarse Aggregate in Concrete: A Systematic Review of Mechanical Performance, Durability, and Sustainability aims to systematically analyze the latest literature related to the use of iron slag as a partial replacement for coarse aggregate in concrete, specifically from the aspects of mechanical performance, durability, and sustainability. This study uses a Systematic Literature Review (SLR) approach guided by the PRISMA framework through article searches in Scopus, Web of Science, DOAJ, ERA, MyCite and Google Scholar databases. A total of 76 initial records were identified, 24 duplicate records were removed, 52 records were screened, 24 full-text articles were evaluated, and finally 14 articles were included in the qualitative synthesis. The findings of the study show that the use of air-cooled blast furnace slag (ACBFS), steel slag, electric arc furnace slag (EAF slag) and Linz–Donawitz slag (LD slag) has the potential to improve the compressive strength, tensile strength, bending strength and modulus of elasticity of concrete when used at optimal replacement rates. However, the performance of concrete is not uniform as it is influenced by slag type, replacement rate, density, surface texture, water absorption rate, and mix design. The significance of this study lies in its contribution in supporting the use of industrial waste as a sustainable building material, reducing dependence on natural aggregates and reinforcing the concept of the circular economy. The new knowledge of this study is a systematic synthesis that links the mechanical performance, durability and sustainability of iron slag in an analytical framework to support the development of low-carbon concrete .Keywords—Iron slag; coarse aggregate; concrete; mechanical properties; systematic literature review.