Reimagining steel slag in sustainable concrete: A bibliometric and experimental review

This review paper offers a comprehensive investigation into the use of steel slag in concrete, integrating bibliometric analysis with experimental findings to evaluate its performance, durability, and sustainability. Steel slag, a by-product of steel manufacturing, is generated in large volumes and presents environmental challenges due to improper disposal and leaching of harmful elements. Simultaneously, the construction industry’s heavy dependence on Portland cement significantly contributes to global greenhouse gas emissions. Owing to its chemical similarity with cementitious materials, steel slag shows promise as a partial replacement for cement and natural aggregates. A bibliometric review of 880 Scopus-indexed publications reveals growing research interest worldwide—particularly in China, India, and Iraq—with main focus areas on mechanical properties, durability, and circular economy strategies. Experimental studies indicate that optimal replacement rates (10–15% for cement, 30–50% for aggregates) enhance compressive strength, chloride resistance, sulphate durability, and freeze–thaw performance. Treatments such as carbonation improve slag reactivity and stability. However, issues remain regarding workability, slag quality control, and extreme condition performance. Future research directions include smart concrete, geopolymer–slag hybrids, and nanomaterial enhancements. Life-cycle analysis and regulatory frameworks are essential for scaling adoption. Overall, steel slag presents a viable, sustainable solution in concrete, promoting resource efficiency and emission reduction.