No abstract

In the two last decades, world production of pig iron and steel has undergone a significant increase. In 2018, 1252.87 and 1806.46 million tons of pig iron and steel, respectively, were produced as compared to the 575.78 and 809.94 million tons of 2000. Consequently, the amount of the different types of slags deriving from these production processes has also increased considerably. In relation to the principles of sustainability and circular economy, the available literature suggests several possible reuses for these slags (bituminous conglomerates, hydraulic engineering, metallurgy, fertilizers, etc.). This paper aims to provide an overview of the iron and steel slags production and their reuse in concrete (for example as replacement of cement, fine or coarse aggregates). The characteristics of slags are analyzed in terms of chemical, physical, and mechanical properties. Mechanical and durability tests (both from material and structures point of view) carried out in the different studies and research are shown as well. Particular attention was devoted to electric arc furnace slags (EAF) since they are the most produced in Italy. Based on this deep literature review, the gaps that still require further studies have been identified and discussed.

The aim of this research work was the evaluation of the feasibility to utilize industrial by-products, such as electric arc furnace steel slags, for sustainable concrete production. The paper evaluated the environmental and mechanical properties of steel slags and concrete, respectively. Specifically, the release of contaminants from steel slags was investigated by leaching test and the properties of fresh and hardened concrete were evaluated for a concrete mixture designed with a partial substitution (30%) of natural coarse aggregates with electric arc furnace steel slags. The results show that the concentrations of pollutants were lower than the legal limits imposed by the Ministerial Decree 186/2006 and the addition of steel slag can enhance the mechanical performance of concrete. The compressive strength of cubic specimens was also measured after different cycles of alternate wetting–drying. The steel slag incorporation results in a stiffness comparable to that of a traditional concrete. Overall, the mechanical and leaching characterization has shown that the reuse of electric arc furnace steel slags for sustainable concrete production is feasible and reliable.