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In this study, a standard pH test procedure, based on the high alkalinity of electric arc furnace oxidizing slag, was developed for rapid content evaluation of potentially hazardous slag in the fine aggregate and recommended standards are further proposed. The advantages of the developed procedure include easy equipment acquisition, simple test method, short time, and high accuracy. This study found that sample size, water source, and filtrate process were the factors affecting the pH test accuracy. In the test, the pH increased with a decrease in the aggregate size when the proportion of electric arc furnace oxidizing slag in aggregate was fixed, especially when the aggregate size was less than 0.225 mm. Upon comparison of the results of autoclaved mortar bar expansion tests, a good logarithmic relationship was observed between pH and electric arc furnace oxidizing slag content. It is suggested that pH 9.0 could be used as the standard to determine excessive electric arc furnace oxidizing slag in fine aggregate. • Proposed a standardized process for rapidly assessing pH in fine aggregates, addressing hazards from electric arc furnace oxidizing slag (EAFOS). • Optimized pH testing factors: D100 particles, RO water, 10 % solid content, filtration through 5A + 5B paper before measurement. • Sample pH values consistently showed a logarithmic relationship with EAFOS content proportion. • pH values over 9.0 indicate excessive EAFOS content in fine aggregates, making them unsuitable for further application. [ABSTRACT FROM AUTHOR]

• Bricks made from AAC achieved a high superiority in compressive strength compared with conventional cement bricks. • Higher glass water decreases AAC setting time and leads to rapid flash setting. • High alkali-activated binder content increases compressive strength, density, and drying shrinkage. • Manufacturing compaction pressure has a significant effect in the enhancement of AAC bricks properties. • Fully green bricks could be made with wasted slag aggregates. Alkali-activated concrete (AAC) has shown high potential as a replacement for ordinary Portland cement concrete (OPCC). It has been found that fresh AAC is usually dry and difficult to control during the casting process, as well as having flash setting issues. In light of the lack of a final form for the use of AAC in construction, there is a need to discover applications that benefit from the advantages of AAC while also being able to deal with its drawbacks. This paper will focus on taking advantage of AAC's defects by using it in a nonstructural application that does not require high-workability concrete, such as producing bricks. Waste from the iron industry was used as the main component for producing the AAC bricks in order to reduce the environmental impact, reduce the cost, and save large quantities of cement and natural aggregates consumed by the brick industry. Ground granulated blast furnace slag (GGBFS) and electric arc furnace slag (EAFS) were substituted for cement and aggregates, mixed along with an alkaline solution and superplasticizer. AAC bricks were produced in the same way as normal concrete bricks. The physical and mechanical properties studied were compressive strength, water absorption, bulk density, efflorescence, and drying shrinkage. Six parameters were considered throughout this investigation. The effects of binder content, cement replacement ratio, alkaline-to-binder ratio, sodium silicate/sodium hydroxide mass ratio, sodium hydroxide molarity, and compaction pressure. The results showed that compared to ordinary bricks, AAC bricks provided high compressive strength up to 92 MPa, up to 54% less water absorption, a density of more than 2.8 t/m3, and a higher drying shrinkage up to 0.002 mm. Furthermore, no signs of efflorescence or salts appeared on the bricks. [ABSTRACT FROM AUTHOR]

• Solid waste-based magnetic response particles. • Active control of rheological properties. • Rheological properties are linearly related to additional energy. Interventions at the print head, such as magnetic fields, are expected to efficiently improve the buildability of 3D printed concrete (3DPC) without compromising flowability. A cement-based magneto-rheological (MR) fluid material has been developed using electric arc furnace slag powder (EAFSP). This paper found that the storage modulus and dynamic yield stress of cement-based MR fluids dramatically increased with the magnetic field strength and EAFSP concentration. According to the linear fitting results, the rheological properties correlate with the additional energy the magnetic moment obtains whenever a constant magnetic field is applied. Furthermore, after a time-limited magnetic sweep, the 3DPC buildability was improved, probably due to the presence of residual chain-like structures. This research assumes significance for the application of set-on-demand 3DPC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Laboratory study of porous asphalt concrete made with electric arc furnace (EAF) steel slag and RAP. • With the use of 30% of RAP and/or 30% of artificial aggregates it is possible to obtain suitable porous asphalt materials. • The results showed the technical feasibility of the experimental porous mixtures. • The environmental assessment compared the porous asphalt mixture to enhance the use of artificial and recycled aggregates. • The LCA analysis proved that RAP and EAF steel slag improve the environmental performances of the porous asphalt mixtures. Porous asphalt mixtures play a remarkable role in road pavement thanks to their advantages to drain water and reduce noise. To meet the always-increasing environmental needs, new porous asphalt mixtures are being developed with the addition of recycled materials. The present paper investigates the physical, mechanical, and functional characteristics of two porous mixtures made with electric arc furnace (EAF) steel slag and reclaimed asphalt pavement (RAP). The properties of the two recycled mixtures are compared with conventional porous asphalt produced with natural aggregates. An LCA analysis is performed with a cradle-to-gate approach to evaluate and compare the possible environmental benefits connected to the production of the experimental porous asphalt. The results coming from the laboratory investigation demonstrated higher mechanical and functional performances related to the use of EAF steel slag and RAP aggregates. The environmental assessment established a reduction of up to 25% of potential impact for the mixture produced with both artificial and recycled aggregates. [ABSTRACT FROM AUTHOR]

• Experimental/numerical framework to design fiber-reinforced EAFS concrete elements. • Synthetic and steel fiber-reinforced EAFS concrete shows good mechanical performance. • Set of experiments is proposed to define the inputs required for the FE model. • Interface elements model synthetic and steel fibers bridging effect accurately. Over recent years, Electric Arc Furnace Slag (EAFS), a by-product of the steel-making industry, has been used as a replacement of natural aggregates to produce high-performance concrete. In EAFS concrete, fibers are normally added to improve post-cracking behavior, thereby prolonging the durability and range of applications of the composite. Despite the rise in its production, the mechanical performance of fiber-reinforced EAFS concrete is still poorly understood, posing important barriers to its daily use. This paper aims to study the effect of fiber materials (steel and synthetic) on EAFS concrete performance. To do so, the paper proposes, firstly, an experimental campaign and, secondly, a numerical simulation to model the effect of fibers both in the pre-cracking and post-cracking stages. Importantly, for the numerical study, an in-house Finite Element (FE) code is developed using interface elements to capture crack propagation. The FE code uses, as input, data obtained in the experimental campaign and is validated against previously unseen experimental results. The overall framework gives important insights on how fibers improve the post-cracking behavior of EAFS concrete and the relevance of fiber material in the overall performance. The validated numerical tool can be used in the future to design EAFS fiber-reinforced concrete structures and therefore increase the applicability of such composite material. [ABSTRACT FROM AUTHOR]

In this paper fatigue behavior of asphalt mixes containing electric arc furnace (EAF) steel slag is evaluated in both aged and unaged conditions. Six sets of laboratory mixtures were prepared. Each set was treated replacing various portions of limestone coarse aggregates (⩾2.36 mm) with EAF steel slag. Four point bending beam fatigue testing was performed in controlled stress mode at various stress levels to characterize the fatigue behavior of the asphalt mixes. Various approaches, based on stiffness and dissipated energy were used to analyze the fatigue tests data which then used to develop fatigue models. Moreover, in order to evaluate long term performance of mixes containing EAF slag, the specimens were subjected to aging according to AASHTO PP2 standard testing method. The results showed that the inclusion of EAF in mixes improved fatigue life of samples considerably. For aged specimens, the fatigue life did not change appreciably. This was as a result of greater stiffness of mixes containing low percentages of EAF slag. This finding approved the hypothesis which was suggested that the greater the adhesion, the greater the mitigation of aging in asphalt mixes. [ABSTRACT FROM AUTHOR]

• Less dependence on PCE for 3DPC with EAFS fine aggregates. • 3DPC with EAFS possesses better flowability and buildability. • The spherical model of EAFS contributes to improved mechanical properties. • EAFS fine aggregates dense packing reduced the 3DPC pore volume. Polycarboxylate ether superplasticizer (PCE) is a popular option for improving the flowability of 3D printed concrete (3DPC). However, the side effects and high cost of PCE impede the development of 3DPC. In recent years, a spherical electric arc furnace slag (EAFS) was produced by a novel production method. It is, therefore, imperative to investigate the usage of EAFS's ball-rolling effect to improve 3DPC flowability. In this paper, the rheological properties, flowability, buildability, mechanical properties, and pore structure of superplasticizer-free 3DPC were determined with EAFS replacing 25%, 50%, 75%, and 100% of river sand (RS). The results were compared with the control sample which contains PCE and 100% RS. The rheological properties proved that both EAFS and PCE improved 3DPC flow initiation, but 3DPC with EAFS achieved a lower viscosity loss rate, which is beneficial to buildability. Under consistent printability conditions, the average flowability value of 3DPC with EAFS was 180 mm, which exceeded the control sample by 15 mm, and the optimum buildability was achieved when 50%–75% of RS was replaced. Furthermore, the EAFS spherical model allowed for significant improvements in 3DPC mechanical properties while also reducing the pore volume. Overall, utilizing EAFS to improve 3DPC flowability successfully eliminates dependence on PCE, while optimizing buildability and mechanical properties, among other benefits. [ABSTRACT FROM AUTHOR]

• Energy efficiency in MW heating is improved by increasing the loss factor ε″. • The incorporation of EAF slag in asphalt mortars increased its loss factor ε″. • Within the 0.1–6 GHz range, the frequency 5.8 GHz yielded the highest value of ε″. • Microwave radiation at a frequency of 5.8 GHz can penetrate the pavement 7 cm. Microwave (MW) heating could contribute to the sustainability of the construction and maintenance of asphalt pavements. The relationship between frequency and the dielectric properties (i.e. loss factor and penetration depth) is crucial for maximising the MW heating efficiency. The paper aims to study the dielectric properties of conventional and electric arc furnace (EAF) slag asphalt mortars. Results showed that the addition of EAF slag enhanced the dielectric response of asphalt mortars. Moreover, a frequency of 5.8 GHz seems to be the best choice for deicing application and assisted-healing of surface layers up to 7 cm. [ABSTRACT FROM AUTHOR]

• It is possible to use EAFS as a precursor for geopolymer. • The incorporation of FA has a positive effect on the fresh and hardened properties of EAFS geopolymer. • Including FA in EAFS geopolymer can hinder the formation of microcracks and refine the microstructure. The precursors of alkali-activated materials (AAMs) have major effects on their properties. More attention was paid to using by-product precursors such as slag and fly ash (FA) for AAMs, whilst less attention was paid to using another by-product precursor such as electric arc furnace slag (EAFS). The use of EAFS as a geopolymer precursor is still under the development stage. Thus, the current paper aims to study the fresh and mechanical properties, as well as durability of EAFS geopolymer cement activated with NaOH and sodium silicate solution. The durability was studied by two parameters named water absorption and chloride penetration permeability. To improve the properties of EAFS geopolymer cement, EAFS was partially replaced with 15–60 wt% FA. X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to analyze the results. The results showed modified properties of EAFS geopolymer cement with the incorporation of FA such as high flowability, high mechanical strength, low water absorption, low charge passed, preventing the formation of microcracks, refining and densifying the microstructure. [ABSTRACT FROM AUTHOR]

• The thermomechanical treatment consists of a heating treatment and a re-compaction. • The only heating treatment allows to recover up to 60% of the initial resistance. • The synergy of temperature + re-compaction recovers 100% of the initial resistance. • At laboratory: 60 °C + 100 gyrations optimise the energy consumed in the treatment. • The use of 10% of electric arc furnace slag can double the energy efficiency. A combination of heat and re-compaction energy (thermomechanical treatment), can be applied to damaged asphalt pavements for assisted healing purpose. This paper aims to optimise the thermomechanical treatment in hot asphalt mixtures by defining the temperature and the re-compaction energy that maximises the healing and minimises energy consumption. This laboratory study showed that the asphalt mixture had a poor healing performance by only applying heating energy. In contrast, the application of re-compaction energy significantly improved healing results. The heating temperature of 60 °C and re-compaction energy of 100 gyrations with the gyratory compactor is sufficient for the complete healing of the hot asphalt mixtures under study. Moreover, the addition of Electric Arc Furnace (EAF) slag allows obtaining the same healing results with half of the energy consumed, improving this technology's sustainability. [ABSTRACT FROM AUTHOR]

• A feasible technical route for utilizing deposited BOFSS in concrete is proposed. • The replacement ratio of BOFSS coarse (SSCA) and fine (SSFA) aggregates is optimized. • Improvement in compressive strength of concrete is achieved with an optimum replacement ratio of SSCA and SSFA. • BOFSS can significantly improve the interfacial transition zone (ITZ) of concrete. As an industrial by-product of steel manufacturing, steel slag would cause severe farmland occupation, water pollution and other environmental issues. It can be further categorized into basic oxygen furnace (BOF), electric arc furnace and ladle furnace slags, in which BOF steel slag (BOFSS) accounts for nearly 70% of the total steel slag production in mainland China. Therefore, massive consumption of BOFSS in reasonable fields is of unprecedented significance for resource recycling and environmental conservation. In this paper, BOFSS was adopted to replace coarse and fine aggregates of ordinary concrete to produce "Greener" concrete. A total of 15 concrete mixes with different replacement ratios of coarse and fine aggregates using BOFSS were designed, the mechanical property and microstructure (mercury intrusion porosimetry and scanning electron microscope tests) of which were studied. Results revealed that the optimum replacement ratios of coarse and fine aggregates were 50% and 30%, respectively. With these ratios, the later-age compressive strength and microstructure of concrete could be significantly improved. Therefore, it is concluded that the use of BOFSS in concrete not only benefits the environmental protection and material greenness, but also improves the behavior of concrete, which provides a win-win solution. [ABSTRACT FROM AUTHOR]

• Hot weather causes problems for transporting, placing and consolidation of concrete. • Retarding admixtures are generally liquid-based, and they have short shelf-life. • Electric arc furnace dust, an industrial byproduct, was used as a set retarder. • Electric arc furnace dust is similar to or better than commercial retarders. • The use of electric arc furnace dust results in economic and environmental benefits. Retarding admixtures are used to increase the setting time of concrete, especially under hot weather conditions. They provide longer time for concrete to be transported, placed and consolidated. Several commercial retarders are used to extend the setting time of concrete. However, they have a shorter shelf-life as they are commonly supplied in a liquid form. Consequently, there is a need to develop a solid (powder) set retarder that can be efficient in retarding the setting time of concrete and at the same time have a longer shelf-life. This paper presents the results of a study conducted to assess the possibility of developing a set retarder utilizing electric arc furnace dust (EAFD), a by-product of steel industry. The retardation efficiency of up to 6% EAFD, by weight of cement, was evaluated in comparison with other two commercial retarders. The effect of EAFD addition on the heat of hydration, slump retention, compressive strength, and drying shrinkage was evaluated. The experimental data indicated that EAFD is effective in increasing the initial and final setting time. The calorimetry data indicated that the hydration of cement was delayed due to the addition of EAFD. The 28-day compressive strength of concrete was not adversely affected by EAFD or the commercial retarders, and it was in the range of 46.5 MPa to 50.7 MPa. However, the drying shrinkage strain increased by 24 to 37%. It can be concluded that the performance of the solid retarder developed using EAFD was comparable to that of the commercial retarders. The use of EAFD, an industrial byproduct, as a retarder will result in technical, economic and environmental benefits. [ABSTRACT FROM AUTHOR]