Ladle slag characteristics and use in mortar and concrete: A comprehensive review

Abstract Ladle slag is a by-product of secondary steel treatment. A typical management option for ladle slag is stockpiling in open yards. Given the massive production quantities of such material, this disposal mechanism has posed major environmental concerns over the years. The construction industry is a potential area that may recycle ladle slag as a sustainable replacement to cement binder, thereby reducing the consumption of cement, conserving natural resources, and alleviating greenhouse gas emissions. Accordingly, this paper provides a state-of-the-art review of the generation, characteristics, and reaction mechanisms of ladle slag. The effect of utilizing ladle slag on the fresh and hardened properties and microstructure of alkali-activated mortar and cement-based conventional and self-compacting concrete is also reviewed. Findings highlighted that utilizing ladle slag by the concrete industry is possible with favorable properties when certain preprocessing measurements, such as milling, sieving, and gypsum addition, are implemented. Furthermore, it is concluded that the degree of reaction and performance of alkali-activated mortar and concrete are dependent on the curing temperature and the type and components of the alkaline activator solution. Also, the replacement of 20% cement with ladle slag does not compromise the strength and durability aspects of cement-based concrete. From an environmental perspective, ladle slag is considered a non-hazardous material suitable for use in construction applications. The research gaps in the existing knowledge and future research directions are also identified.