Slag-based Binder Research Articles

Image analysis as a geometry- and integrity-independent tool for predicting strength of cemented tailings backfill using slag-based binder

Compressive strength is a crucial indicator for assessing the stability of the cemented tailings backfill (CTB) matrix. The stringent requirements of traditional non-destructive testing (NDT) methods (e.g., ultrasonic pulse velocity and electrical resistivity) regarding the geometry, section flatness, and integrity of the core sample severely limit their use in the in-situ measurement of CTB strength. Therefore, this study proposes a novel NDT technique for assessing the in-situ strength of CTB made from ground granulated blast furnace slag (slag) by means of image analysis. Strength tests and image analysis are carried out in 258 specimens maintained at different solid concentrations (71−79 %), binder contents (6−14 %), activator ratios (from 28:2–20:10) and curing temperatures (5−40℃). In addition, microscopic investigations are carried out to clarify the underlying mechanisms contributing to the macroscopic features. Increasing solid content, desulfurized gypsum to calcium carbide slag (DG/CS) ratio, and curing temperature results in increases in UCS of 87.9−199.9 %, 171.3−421.2 %, and 27.5−173.8 %, respectively. The strength-enhancing effect of increasing the curing temperature diminishes with time, from 173.8 % at 3 days to 27.5 % at 28 days. Strength initially rises and then abruptly decreases as binder content rises. The grayscale value generally has an opposite trend to strength, but the former is less sensitive to changes in influencing factors. An obvious exponential relationship is found between strength and grayscale for all specimens (R2 = 0.92). Compared with traditional NDT methods, the application of image analysis is not restricted to the shape, size, and integrity of CTB and therefore provides a faster, easier, and less costly tool for the quality evaluation of field CTB matrix.

Hybrid Organic-Inorganic Blast Furnace Slag Binders Activated with Alkali Acetates.

Hybrid organic-inorganic binders based on blast furnace slag were produced using sodium (NaAc) or potassium (KAc) acetate as the sole activator, and their properties were compared with those of sodium- or potassium hydroxide-activated slag pastes. The acetate-activated binders showed significantly lower cumulative heat release and extended setting time (∼230 h) than the hydroxide-activated binders. The main reaction products forming in all binders were calcium aluminosilicate hydrate-type gels and a hydrotalcite-like phase, independently of the activator type used. Compressive strengths of the acetate-activated pastes (∼40 MPa at 180 days) were lower than those of the hydroxide-activated binders (∼80 MPa at 180 days). However, the acetate-based binders exhibited superior impermeability and reduced wettability at 28 days, likely due to hydrophobic acetate groups. It is hypothesized that acetates dissociate in water, forming calcium acetate and alkali silicates via a reaction with species dissolving from the slag. This study demonstrates alkali acetates are effective activators for creating hybrid slag-based binders with reduced permeability.

Probabilistic Corrosion-free Service Life of the RCC Structures Made with OPC and Ultra-fine Slag-based Binders

The primary factor in the deterioration of reinforced concrete is chloride-induced corrosion. It has a direct impact on the service life of the structure and has been the subject of much research over the past 5 decades. One of the most cost-effective ways to lessen chloride-induced corrosion was identified to be the use of more supplementary cementitious material (SCM). Moreover, when SCMs are ground down to a smaller size, the resulting particles serve as microfillers, which have a significant impact on the improvement of mechanical properties and durability. This paper highlights the influence of grinding slag into an Ultra Fine Slag (UFS) on chloride ion penetration in the mortar specimen. A bulk diffusion test was performed on a mortar replaced with UFS which show a synergic reduction in chloride diffusivity in comparison with control mixes. In addition, an attempt is made on prediction of probabilistic service life estimation by Error function model.

Influence of ligands as chemical admixtures in the early hydration of sodium carbonate-activated blast furnace slag

Insufficient strength performance at early age impedes the use of sodium carbonate (SC) activator to produce sustainable blast furnace slag-based binders. To solve this issue, this study aimed to accelerate the early hydration kinetics of SC-activated slag system using ligand admixtures: triethanolamine (TEA), triisopropanolamine (TIPA), trisodium nitrilotriacetate (NTA), tetra potassium pyrophosphate (TKPP), and 2,3-dihydroxynapthalene (DHNP). Effect of ligands were investigated by isothermal calorimetry, compressive strength determinations, workability tests, XRD analysis, TGA, and batch dissolution tests. Results showed that the effect of the ligand on the reaction mechanism and strength development depends on the ligand functional group, concentration, and dissolution and metal complexing properties. Between the investigated ligands, 25 mM of DHNP accelerated the hydration kinetics by 28 h and produced 2-day strength of 41 MPa compared to the reference of only 2 MPa. Mechanism behind this acceleration is by affecting the ion activity product (IAP) of layered double hydroxides (LDHs) or C-(A)-S-H phases and not hindering the underlying carbonate salts (gaylussite, calcite) precipitation kinetics. These findings show the potential of ligands as admixtures in binder forming reactions and holds the key to potentially develop and fine tune sustainable low-CO2 binders.

Cementitious Composites with Cellulose Nanomaterials and Basalt Fiber Pellets: Experimental and Statistical Modeling

The production of high-performance fiber-reinforced cementitious composites (HPFRCCs) as a durable construction material using different types of fibers and nanomaterials critically relies on the synergic effects of the two materials as well as the cementitious composite mixes. In this study, novel HPFRCCs were developed, which comprised high content (50%) slag by mass of the base binder as well as nano-silica (NS) or nano-crystalline cellulose (NCC). In addition, nano-fibrillated cellulose (NFC), and basalt fiber pellets (BFP), representing nano-/micro- and macro-fibers, respectively, were incorporated into the composites. The response surface method was used in this study’s statistical modeling part to evaluate the impact of key factors (NS, NCC, NFC, BFP) on the performance of 15 mixtures. The composites were assessed in terms of setting times, early- and late-age compressive strength, flexural performance, and resistance to freezing-thawing cycles, and the bulk trends were corroborated by fluid absorption, thermogravimetry, and microscopy tests. Incorporating NS/NCC in the slag-based binders catalyzed the reactivity of cement and slag with time, thus maintaining the setting times within an acceptable range (maximum 9 h), achieving high early- (above 33 MPa at 3 days) and later-age (above 70 MPa at 28 days) strength, and resistance to fluid absorption (less than 2.5%) and frost action (DF above 90%) of the composites. In addition, all nano-modified composites with multi-scale fibers showed notable improvement in terms of post-cracking flexural performance (Residual Strength Index above 40%), which qualify them for multiple infrastructure applications (i.e., shear key bridge joints) requiring a balance between high-strength properties, ductility, and durability.

Alkaline activation for production of slag-based binders from the manufacture of manganese ferroalloys

The growing demand for sustainable development across different sectors is creating opportunities for research and development of products that incorporate waste materials in their production processes. One of the technologies that has gained prominence in this regard is the alkaline activation process, known for its low energy consumption and environmentally sustainable characteristics. In this sense, this work presents an evaluation of the application of slag generated in a manganese ferroalloy manufacturing plant as a precursor to alkali-activated binders. Grounded silico-manganese slag and NaOH at different molarities were used to prepare samples, which were then cured at room temperature (25 ± 2 °C). The rheological properties of the pastes and the technological properties of compressive strength and water absorption were analyzed. In addition, microstructural analysis was performed using XRD, TG/DTA, SEM/EDS, and FTIR. The results showed that the shear stress increases with NaOH molarity, and viscosities are higher for the paste with the lowest molarity. The maximum 91-day compressive strength of 14.4 MPa was achieved with a 6 M solution, and for this condition, the mass loss was 0.2%. Integrating SEM micrographs with TG/DTA, XRD, and FTIR analysis supports the hypothesis of gel phase precipitation during the synthesis of the alkali-activated binder. Thus, incorporating this slag into the production of an alkali-activated binder demonstrates the potential to revitalize this manufacturing process, which could lead to the adoption of clean and environmentally sustainable technologies in industrial processes.

Leaching and hydrating mechanisms, economic benefits of backfill materials by using coal fly ash–slag-based binder for environmentally sustainable production

Herein, the blast furnace slag (BFS), steel slag (SS), desulphurisation gypsum (DFG) and mechanically modified fly ash (MFA) were used as a coal fly ash–slag-based binder (FSD) for the solidification/stabilisation (S/S) of non-ferrous metal tailings and to prepare a coal fly ash–slag-based backfill materials (FST). The results revealed that the optimal ratio for FST was G9I-2, which consisted of 20% MFA, with an appropriate fluidity (240 mm) and setting time (13 h) that satisfied the backfill pipeline transportation requirements, and compressive strengths with 7 and 28 d curing of 2.43 and 8.47 MPa, respectively. The diffusion coefficient (Do) of FST ranged from 2.13 × 10−11 to 2.50 × 10−10 cm2/s, with a leachability index (LI) of 10.08–10.54. These values indicated that the FSD effectively encapsulated Pb and Zn by S/S, with G9I-2 exhibiting the lowest risk of leaching and the leaching mechanism of Pb and Zn was dissolution. The solidification of lead and zinc primarily occurred through the formation of hydration products such as C–(A)–S–H gel, possibly forming a complex salt phase. The addition of an appropriate amount of MFA (20 wt%) increased the content of functional hydration products (15%, ettringite; 14%, complex salt mineral phase) and the degree of polymerization. An increase in the Al/Si ratio (0.11087 ± 0.00948 ∼ 0.38838 ± 0.01935) in the gel region of G9I-2 indicated the continuous transformation from C–S–H to C–A–S–H phase. Life cycle assessment (LCA) and economic benefit analysis (EBA) demonstrated that FST materials significantly reduced CO2 emissions (0.45 kg/t) and generated significant economic benefits (2.76 USD/t) for mine backfill applications. These findings highlight the significance of MFA in achieving sustainable and high-performance construction materials, with potential applications in various construction projects.

Full-scale sustainable structural concrete containing high proportions of by-products and waste

The construction industry in general is, through minor low-cost processing methods, converting several of its by-products into viable materials; furthermore, some siderurgic sector by-products are likewise of use. In this context, large-scale batches (mix volumes over 0.5 m3) of good quality structural concrete are proposed, in which two kinds of binder and two kinds of aggregate (steel slag and recycled concrete) are used to perform four concrete mixtures, containing more than 80 % in mass of good-quality recycled materials. A batch of tests, both in the fresh and in the hardened state, are performed, covering on-site placement and long-term properties, to guarantee the suitability and the quality of the mixtures as structural concretes. Most of the results were encouraging, mainly depending on the aggregate and the binder types that were used. The fresh-state workability of all the test mixtures was good. All the results in terms of hardened properties, strength (42 MPa in type I cement mixtures, and 32–38 MPa in type III cement mixtures), stiffness, long-term shrinkage, and microstructural state (porosity, permeability) were acceptable, their quality depending on the type of each component. The good results of the mixtures based on the slag-based binder deserve attention. Some weak points found were the slightly higher specific weight of the slag aggregate mixes (amounting to more than 2.7 Mg/m3), plastic shrinkage rates (in some cases greater than 1.2–1.5 thousand), and loss of resistance against chlorine penetration in recycled concrete mixes. However, drawbacks of that sort are no obstacle to their use in most structural applications.

Influence on fine lead–zinc tailings solidified/stabilised by clinker-free slag-based binder

This study applied steel slag (SS), blast furnace slag (BFS), flue gas desulfurised (FGD) gypsum and fly ash (FA) as clinker-free cementitious materials for fine lead–zinc tailing (LZT) backfillings and investigated the mechanism of Pb and Zn immobilisation in tailings. In a binder with 42%, 42% and 16% of SS, BFS and FGD gypsum, respectively, the binder-to-tailings ratio was 1:4. Additionally, the slurry concentration was 78%, resulting in unconfined compressive strength values of 0.89, 6.47 and 11.03 MPa after 7, 28 and 56 d, respectively, and fluidity of 230 mm. After 56 d of curing, the leaching concentration of Pb and Zn became 0.34 and 0.63 μg/L, respectively, and the immobilisation efficiency and the bioavailability reduction efficiency of Pb and Zn were 99% and 90%, respectively, which are lower than the underground class III water standard. Additionally, the double salt effect was a crucial reason for the excellent immobilisation properties of Pb and Zn. Micro-analysis indicated that anglesite, minrecordite and Pb[Fe3(SO4)2(OH)6]2 formed during the hydration process with their solubility products (Ksp) at 1.622 × 10−8, 1 × 10−20 to 1 × 10−16 and 1 × 10−25.5 at 25 °C. Furthermore, the residues of Pb and Zn in the morphological analysis increased from 29% and 37% (the original) to 65% and 67% (curing 56 d), corresponding to the increasing binding energy and content of Zn–O and Pb–O. Moreover, calcium–silicate–hydrate gel and ettringite appeared in the solidified samples, with a high degree of cementation, as the hydration age increased.

Preparation and performance of composite activated slag-based binder for cemented paste backfill

The utilization of blast furnace slag (BFS) and fly ash (FA) to replace ordinary portland cement (OPC) has become a hot topic in the preparation of low-cost cemented paste backfill (CPB). This study has prepared a composite activated slag-based binder (CASB) using BFS and FA as the basic raw materials and desulfurization gypsum (DG) and cement clinker (CC) as the activator. The optimum ratio of CASB was determined based on the orthogonal test and the efficacy coefficient method. The hydration products and hydration mechanism of CASB materials were further investigated using XRD, TG, and SEM tests; on this basis, the compressive strength of hardened CASB-CPB under different working conditions and the rheological properties of fresh slurry were investigated, and the cost analysis and environmental effects of CASB were carried out. The results show that the optimum ratio of CASB was 15:12:13:60 for FA: CC: DG: BFS; the hydration mechanism of CASB was the coupled alkali-sulfate activation of CC and DG, and the main hydration products were hydrated calcium silicate gels (C–S–H gels) and ettringite (AFt); increasing the mass concentration (Cw) at a constant cement-aggregate ratio (C/A), which caused a significant improvement in the compressive strength at 7 and 28 d while reduced the flowability of the slurry; CASB considerably reduced the filling cost compared to OPC, and effectively immobilization the heavy metals in the tailings. This paper has developed a cement alternative binder of CASB, which has considerable significance for the comprehensive utilization of solid waste, reduction of filling costs, and improvement of economic and ecological benefits of the mine.

Hydration kinetics and performance of sodium carbonate-activated slag-based systems containing reactive MgO and metakaolin under carbonation

The hydration mechanism and strength development of sodium carbonate-activated slag-based systems mainly depend on the additives used. Although the effects of mineral additives in such systems have been extensively investigated, the effects of Mg2+, Al3+, and Si4+ ions increasing with the addition of reactive MgO (Mg) and metakaolin (Mk) on the hydration mechanism of such systems have not been established yet. This study investigated the hydration kinetics and performance of sodium carbonate-activated ternary blended slag-based binder systems. The hydration mechanism was revealed by isothermal calorimetry and mechanical performance was evaluated with the measurement of compressive strength at different ages up to 56 days. The reaction mechanisms were investigated through X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and 29Si and 27Al solid-state nuclear magnetic resonance (NMR). C-(A)-S-H, Na and Al-enriched C-(N,A)-S-H and hydrotalcite were the main reaction products responsible for the strength development of the samples, accompanied by the minor contribution of other carbonate-containing phases. Partial replacement of slag with Mg and Mk led to high early-age strengths compared to plain samples when Mk was used at 5%. Samples incorporating Mg and Mk achieved similar or higher strengths than ordinary Portland cement-based samples. However, an increase in replacement ratio of Mk beyond 5% led to a significant decrease in compressive strength. Furthermore, the performance of samples under accelerated carbonation was studied. The use of Mg and Mk enhanced carbonation resistance due to enhanced hydrotalcite and C-(N,A)-S-H gel formation, highlighting the potential of using slag-Mg-Mk blends as an alternative binder system.

Improving sulphuric acid resistance of slag-based binders by magnesium-modified activator and metakaolin substitution

Alkali-activated slag (AAS) is an appealing alternative to ordinary Portland cement (OPC) in aggressive acid environment considering its relatively low calcium content and potential in retarding aggressive media penetration. This study evaluates the effect of reactive MgO–NaOH mixture as an activator on the performance of AAS with and without metakaolin substitution upon sulphuric acid exposure. The experimental results reveal an improved acid resistance of slag pastes with supplementary magnesium and the improvement is further enhanced with 20% metakaolin substitution. The improved effect by supplementary magnesium is not only attributed to its microstructure refinement for retarding acid penetration; but also contributed by the acid neutralisation capacity of the formed brucite and the potentially positive effect of magnesium on stabilising the AAS binding gel. Stratified silica-rich gels are formed in the metakaolin-substituted AAS, whose formation is primarily attributed to the intrinsic difference of the formed aluminosilicate gels and related to the pH value and the presence of Mg2+. Considering the dense structure of these gels, they might act as protective barriers for the AAS upon acid deterioration.

Study on Solidification and Stabilization of Antimony-Containing Tailings with Metallurgical Slag-Based Binders

Blast furnace slag (BFS), steel slag (SS), and flue gas desulfurized gypsum (FGDG) were used to prepare metallurgical slag-based binder (MSB), which was afterwards mixed with high-antimony-containing mine tailings to form green mining fill samples (MBTs) for Sb solidification/stabilization (S/S). Results showed that all MBT samples met the requirement for mining backfills. In particular, the unconfined compressive strength of MBTs increased with the curing time, exceeding that of ordinary Portland cement (OPC). Moreover, MBTs exhibited the better antimony solidifying properties, and their immobilization efficiency could reach 99%, as compared to that of OPC. KSb(OH)6 was used to prepare pure MSB paste for solidifying mechanism analysis. Characteristics of metallurgical slag-based binder (MSB) solidified/stabilized antimony (Sb) were investigated via X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). According to the results, the main hydration products of MSB were C-S-H gel and ettringite. Among them, C-S-H gel had an obvious adsorption and physical sealing effect on Sb, and the incorporation of Sb would reduce the degree of C-S-H gel polymerization. Besides, ettringite was found to exert little impact on the solidification and stabilization of Sb. However, due to the complex composition of MSB, it was hard to conclude whether Sb entered the ettringite lattice.

Reaction Kinetics and Characterization of Slag-Based, High Strength, “Just-Add-Water” Type (One-Part) Alkali-Activated Binders

The influence of different levels of alkalinity, expressed using M2O-to-binder ratio (n) and activator SiO2-to-M2O ratio (Ms), (M being the Na+ or K+ cation) on the reaction kinetics, compressive strength development and the reaction product formation in slag-based systems activated using alkali powders are discussed. The fundamental idea is to better understand one-part, “just-add-water” type alkali activated binders that are easy-to-use than the systems that rely on liquid activators. The difference in the behavior of the systems with changes in the cationic species (Na+ or K+) and the overall levels of alkalinity is elucidated. Heat release and its rate, and thermal analysis and Fourier Transform Infrared Spectroscopy (FTIR) are used for the characterization of the reaction and the products formed. The influence of activator alkalinity on the initial dissolution and acceleration phases is examined using isothermal calorimetry. An increase in Ms is found to result in reduced early-age and slightly increased later-age compressive strengths. The activator cationic species influences later-age strengths, with K-silicate activated mortars showing a higher strength. The strength data is related to the C-(A)-S-H gel formation. The study shows that slag-based binders can be proportioned to obtained compressive strengths in excess of 80 MPa at later ages (56 days), and up to 30 MPa within 72 hours. The optimal alkali levels based on n and Ms for both the Na- and K-based activator systems are determined.

Alkaline Activation for the Production of Slag-Based Binders from the Manufacture of Manganese Ferroalloys

Alkaline Activation for the Production of Slag-Based Binders from the Manufacture of Manganese Ferroalloys

Effect of Different CO2 Treatments on the Metal Leaching in Steel Slag Binders

Carbonation is an effective method to promote the quality of the steel slag binder. In this article, two carbonation approaches, namely hot-stage carbonation and accelerated carbonation, were employed to leach the metals, and the influence mechanism on the metal sequential leachability of the binders composed of 80 wt% of EAF slag incorporating 20 wt% of Portland cement (PC) was revealed. The carbonate products, microstructures, and chemical states were investigated, and the results indicated that chromium, vanadium, and titanium gradually transformed into inactive phases after two carbonation approaches, while zinc appeared the opposite trend. The sequential leachability of chromium declined with the increase of the carbonation efficiency, in which the exchangeable chromium decreased from 1.99 mg/kg in the A2A binder to below the detection limit in the A2C binder and C2C binder. Hot-stage carbonation treatment facilitated particle agglomeration, minerals remodeling, and calcite formation. The carbonation curing of the steel slag paste resulted in the formation of amorphous CaCO3, calcite crystalline and Si-bearing hydrates that covered the pores of the matrix, and silicate structure with a higher disorder. The hot-stage carbonation and accelerated carbonation curing methods were adopted to jointly prevent the leaching of harmful metals and facilitate promising high-volume steel slag-based binders with structural densification and CO2 storage.

Solidification/Stabilization of Arsenic-Containing Tailings by Steel Slag-Based Binders with High Efficiency and Low Carbon Footprint.

The disposal of nonferrous metal tailings poses a global economic and environmental problem. After employing a clinker-free steel slag-based binder (SSB) for the solidification/stabilization (S/S) of arsenic-containing tailings (AT), the effectiveness, leaching risk, and leaching mechanism of the SSB S/S treated AT (SST) were investigated via the Chinese leaching tests HJ/T299-2007 and HJ557-2010 and the leaching tests series of the multi-process Leaching Environmental Assessment Framework (LEAF). The test results were compared with those of ordinary Portland cement S/S treated AT (PST) and showed that the arsenic (As) curing rates for SST and PST samples were in the range of 96.80–98.89% and 99.52–99.2%, respectively, whereby the leached-As concentration was strongly dependent on the pH of the leachate. The LEAF test results showed that the liquid–solid partitioning limit of As leaching from AT, SST, and PST was controlled by solubility, and the highest concentrations of leached As were 7.56, 0.34, and 0.33 mg/L, respectively. The As leaching mechanism of monolithic SST was controlled by diffusion, and the mean observed diffusion coefficient of 9.35 × 10−15 cm2/s was higher than that of PST (1.55 × 10−16 cm2/s). The findings of this study could facilitate the utilization of SSB in S/S processes, replacing cement to reduce CO2 emissions.

Study on the strength, leachability, and electrical resistivity of lead-contaminated soil solidified with a slag-based binder

Study on the strength, leachability, and electrical resistivity of lead-contaminated soil solidified with a slag-based binder

Enhancing Arsenic Solidification/Stabilisation Efficiency of Metallurgical Slag-Based Green Mining Fill and Its Structure Analysis

To dispose of arsenic-containing tailings with low carbon and high efficiency, sodium sulphate (Na2SO4), sodium hydroxide (NaOH), calcium nitrate Ca(NO3)2 and calcium hydroxide Ca(OH)2 were independently added to metallurgical slag-based binder (MSB) solidification/stabilisation (S/S)-treated tailings (MSTs) to enhance the MST arsenic S/S performance. Results showed that only Ca(OH)2 could increase the unconfined compressive strength of MST from 16.3 to 20.49 MPa and decrease the leachate As concentration from 31 μg/L to below 10 μg/L. Na3AsO4·12H2O and NaAsO2 were used to prepare pure MSB paste for mechanism analysis. The results of microstructure analyses showed the high specific surface area and amorphous properties of calcium–sodium aluminosilicate hydrate facilitated the adsorption or solid-solution formation of As(V) and As(III). As(V) formed an inner-sphere complex in ettringite, whereas As(III) formed an outer-sphere complex, and the relatively larger size and charge of As(V) compared with SO42− restrict substitution inside channels without affecting the ettringite structure under high loading of As(V). The added Ca(OH)2 promoted the hydration reaction of MSBs and facilitated the formation of a Ca–As(V) precipitate with low solubility, from Ca4(OH)2(AsO4)2·4H2O (Ksp = 10−27.49) to Ca5(AsO4)3(OH) (Ksp = 10−40.12). This work is beneficial for the application of cement-free MSB in the S/S process.

Sodium hydroxide substitution in slag activating mixes: A potential pathway to more sustainable slag-based binders

Alkali-activated slag is commonly used as a cement substitute to reduce the environmental footprint of construction materials. Nonetheless, the use of significant amount of alkaline activators, such as sodium silicate or sodium hydroxide, can be detrimental in terms of global warming potential impact. The aim of this work is to use complementary activators as partial replacement of sodium hydroxide, and therefore reduce the environmental footprint of the activated slag binder. Calcium hydroxide, calcium carbonate, calcium sulfate and magnesium oxide are used as complementary activators in binary or ternary activating mixes. The compressive strength at 28 days are higher (up to 18%) for the calcium carbonate and calcium sulfate-activated samples as compared to the reference activated with sodium hydroxide only. The characterization of the microstructure shows that the proportion of activated slag and the nature of hydrates formed depend on the nature of complementary activators. Calcium aluminum silicate hydrates and hydrotalcite are favored by the presence of calcium carbonate and magnesium oxide, and a sodium calcium aluminum sulfate hydrate is formed in the presence of calcium sulfate. The life cycle impact assessment (LCIA) performed on the different formulations shows that a partial substitution of sodium hydroxide is a potential option to develop more sustainable slag-based binders.