The Use of Steel Slags in Asphalt Pavements: A State-of-the-Art Review

Abstract

Steel slag is a by-product obtained through the separation of molten steel from impurities in steel-making furnaces. It can be produced by different types of furnaces (blast, basic oxygen, electric arc, ladle furnaces). The reuse of metallurgical slags in road pavements can pursue aims of recycling and environmental sustainability. Based on the extensive literature, the paper presents a state-of-the-art review concerning the use of slags in asphalt pavements, discussing the main controversial literature findings. Slag manufacturing processes, chemical, morphological, and physical characteristics, affect its contribution to the asphalt mixture, when it partially or fully substitutes natural aggregates. Legislative state-of-the-art environmental issues, weathering, and leaching aspects are also discussed. The main mechanical and durability properties of pavements containing different types of slags are analyzed based on laboratory and field studies. Generally, the higher mechanical properties of steel slag suggest that its inclusion in asphalt mixtures can provide high-performance pavement layers (excellent strength and stiffness, superior rutting and fatigue resistance, low moisture susceptibility). However, several research gaps still exist (e.g., mix design and seasoning procedure, bitumen–aggregate affinity, low-temperature behavior, brittleness); they are discussed to direct possible future study efforts to clarify specific technical aspects, such as, for example, the effect of slag morphology and physical properties on the final mix properties and the development of specific mix design guidelines.

The Incorporation of Ladle Furnace Slag in Fire Insulating Gypsum-Based Materials

“…and concretes. Additionally, white slag can find use in soil and firm stabilization [5], asp pavement construction [6,7], the production of alkali-activated cements [8,9], brick m facturing [10], waterproofing beds in hydraulic or fluvial works [11], soil acidity correc in agriculture [12], the fixation of ions in water purification processes in environmenta gineering [13], and the development of fishing blocks in aquaculture [13].…”

“…However, there are interesting applications for white slag in the future, such as in clinker manufacture and as a partial substitute for aggregates and/or cement in mortars [3,4] and concretes. Additionally, white slag can find use in soil and firm Fire 2023, 6, 416 2 of 14 stabilization [5], asphalt pavement construction [6,7], the production of alkali-activated cements [8,9], brick manufacturing [10], waterproofing beds in hydraulic or fluvial works [11], soil acidity correction in agriculture [12], the fixation of ions in water purification processes in environmental engineering [13], and the development of fishing blocks in aquaculture [13].…”

Analyzing the Relationship between Compressive Strength and Modulus of Elasticity in Concrete with Ladle Furnace Slag

“…LFS is a by-product obtained during steel refining in ladle furnaces that has the appearance of a grayish powder [32][33][34]. Its chemical composition is mainly based on calcium, silicon, and aluminum oxides [35][36][37] and is similar to that of ordinary Portland cement [38,39].…”

Performance Analysis of Industrial-Waste-Based Artificial Aggregates: CO2 Uptake and Applications in Bituminous Pavement

“…Shen et al [12] simulated a skid resistance degradation process for tunnel pavements as a function of dosage and applied loads; they proposed that the surface texture, pore gradation, and micromorphology are the crucial factors influencing the stabilization rate of the skid resistance. However, the high water absorption and complex porous morphologies of steel slag were found to directly impact the water resistance of bituminous mixtures due to the presence of f-CaO content with high hydration expansion [13,14]. Lyu and Guo et al [15,16] analyzed the evolution of the deterioration of water resistance, utilizing varying dosages of steel slag under dry-wet or freezing-thawing regimes.…”