REVIEW OF CONCRETE PROPERTIES MODIFIED BY THE USE OF SLAG AS FINE AND COARSE AGGREGATES

Abstract

The growing demand for sustainable and durable construction materials has intensified research into alternative cementitious and aggregate resources. This review compares the performance of major industrial slags—Blast Furnace Slag (BFS), Steel Slag, Copper Slag, Phosphorus Slag, and Ferrochromium Slag—at their optimal replacement levels, focusing on mechanical, durability, and microstructural characteristics. Studies show that steel slag performs best at 30% coarse and 40% fine aggregate replacement, significantly improving strength. Copper slag at 20% cement replacement enhances compressive strength and reduces porosity. Phosphorus slag used at 20–40% replacement improves long-term strength and lowers chloride permeability. Ferrochromium slag, blended with ferrochrome ash and lime, yields substantial strength and sorptivity improvements with confirmed environmental safety. BFS, commonly used at 30–50% cement replacement, consistently provides strong mechanical and durability performance. Microstructural analyses (SEM, XRD) show denser interfacial transition zones and increased C–S–H formation. Although most slag mixes slightly reduce workability, their overall performance supports their use in sustainable concrete.