A Review of the Influence of Steel Furnace Slag Type on the Properties of Cementitious Composites

Abstract

The type of steel furnace slag (SFS), including electric arc furnace (EAF) slag, basic oxygen furnace (BOF) slag, ladle metallurgy furnace (LMF) slag, and argon oxygen decarburization (AOD) slag, can significantly affect the composite properties when used as an aggregate or as a supplementary cementitious material in bound applications, such as concretes, mortars, alkali-activated materials, and stabilized soils. This review seeks to collate the findings from the literature to express the variability in material properties and to attempt to explain the source(s) of the variability. It was found that SFS composition and properties can be highly variable, including different compositions on the exterior and interior of a given SFS particle, which can affect bonding conditions and be one source of variability on composite properties. A suite of tests is proposed to better assess a given SFS stock for potential use in bound applications; at a minimum, the SFS should be evaluated for free CaO content, expansion potential, mineralogical composition, cementitious composite mechanical properties, and chemical composition with secondary tests, including cementitious composite durability properties, microstructural characterization, and free MgO content.

Preliminary Validation of Steel Slag-Aggregate Concrete for Rigid Pavements: A Full-Scale Study

“…The gradation of all the EAFS fractions is shown in Figure 1, in which its low fines content (<0.063 mm) can be distinguished. This is a common problem of EAFS and it reduces the concrete workability [10]. Its oven-dried density was around 30% higher than that of the natural aggregates traditionally used in concrete, while its water absorption was slightly higher.…”

“…The gradation of all the EAFS fractions is shown in Figure 1, in which its low fines content (<0.063 mm) can be distinguished. This is a common problem of EAFS and it reduces the concrete workability [10].…”

“…Thus, the SAC and SAC/M mixes were of the S3 slump class (slump between 100 and 150 mm), while the SAC/Y mix was of the S2 slump class (slump between 50 and 90 mm). The use of EAFS in concrete usually reduces its workability due to its angular shape and its high density, which hinder its dragging by the cement paste [10]. These aspects were compensated for in this study by the partial use of siliceous sand 0/4 mm of rounded shape, as well as by the addition of a plasticizer.…”

“…This notable decrease of density is explained by the evaporation of water from the mix during setting [36]. This phenomenon is especially noticeable when EAFS is used as an aggregate, because, although it generally has a high water absorption, its high micro-porosity leads the water it absorbs to be quickly released, which in turn usually results in a high density change from the fresh to the hardened state [10].…”

“…Among the different alternative materials that can be employed, the use of by-products from the metallurgical industry stands out [9][10][11]. The emphasis on giving a second life to the waste materials derived from steelmaking is due to the continuous growth of this industry, whose production exceeded 1.8 million tons in 2019 [12].…”