Sustainable belite-ye’elimite-ferrite cement: utilizing ladle metallurgy furnace steel slag for low-cost and carbon-efficient production

Revealing phase evolution mechanism for stabilizing formamidinium-based lead halide perovskites by a key intermediate phase

Hydration of quaternary phase-gypsum system

The use of solid waste as a supplementary cementitious material (SCM) has the potential to reduce CO2 emissions in the cement industry. Sewage sludge ash (SSA), generated during the incineration of municipal wastewater treatment residues, has emerged as a viable SCM candidate for fabricating ternary cementitious systems incorporating cement and limestone. This study systematically investigated the hydration kinetics, phase evolution, and mechanical behavior of SSA-modified ternary composites. The research particularly focused on elucidating the synergistic interactions between SSA components and conventional cement hydrates under different compositions of ternary composites. Experimental results showed that fine SSA particles provided crystal nuclei for the crystallization and precipitation of hydration products and further increased the initial release of hydration heat. Besides, the reactive aluminate and silicate in SSA facilitated its reaction with limestone and the formation of aluminum-containing hydrates and carboaluminate phases. The formation of additional ettringite was also observed when the gypsum content was increased. These additional hydrates filled in the large capillary pores of hardened cement paste, resulting in a denser microstructure and higher compressive strength. The ternary composite incorporating 20% SSA, 10% limestone and 2% gypsum exhibited a compressive strength of 49.54 MPa with a strength activity index (SAI) of 94.56% at 28 days. The excellent mechanical performance of this ternary composite demonstrates its significant potential for the development of low-carbon cementitious materials.

Investigation into relations among technological properties, hydration kinetics and early age hydration of self-leveling underlayments

Effect of dolomite powder on the hydration and properties of calcium sulfoaluminate cements with different gypsum contents

Alite (Ca 3 SiO 5 : C 3 S * ) and calcium aluminate (Ca 3 Al 2 O 6 : C 3 A) are the major phases in Portland cement, which have an essential role in the development of early age properties. The effects of gypsum content, fineness, and Na 2 SO 4 addition on the early‐stage hydration kinetics are investigated for polyphase (co‐sintered) Ca 3 SiO 5 ‐Ca 3 Al 2 O 6 model systems using calorimetry, X‐ ray diffraction, thermal analysis, and solid‐state 27 Al and 29 Si nuclear magnetic resonance (NMR) spectroscopy. The results demonstrate that the hydration of C 3 A significantly affects the hydration of C 3 S. The C 3 S and C 3 A hydration is hindered considerably in severely over‐sulfated systems (where C 3 A hydration is suppressed due to a very high gypsum content) and systems with additional Na 2 SO 4 . Although there is a considerable amount of Al incorporation in the C‐S‐H phase, no clear trends with respect to gypsum content, hydration age or Na 2 SO 4 addition are observed for the Al IV /Si ratios of the C‐S‐H phase determined from 29 Si NMR. With the addition of Na 2 SO 4 , recrystallization of ettringite from the AFm phases is postponed from 1 day to 7 days. *Cement chemistry notation: C‐CaO, S‐SiO 2 , A‐Al 2 O 3 , ‐SO 3 , N‐Na 2 O.

Predicting the rheology of limestone calcined clay cements (LC3): Linking composition and hydration kinetics to yield stress through Machine Learning

This study investigates the influence of various factors on the performance of ternary binders, utilizing statistical approaches. The research focuses on the influence of varying compositions of Portland Cement-Calcium Aluminate Cement-Calcium Sulphate (PC-CAC-CŜ), types and amounts of mineral powders, and chemical admixtures in ternary binders. Using the Taguchi design, the study required a limited number of experimental trials, utilizing a standard orthogonal array of seven factors across three levels. These factors encompassed binder composition (C1-C2-C3), mineral powder types (limestone, quartz, slag), replacement ratio (0%, 25%, 50%), retarder (0%, 0.1%, 0.2%), superplasticizer, viscosity modifying agent (stabilizer) and accelerator (0%, 0.05%, 0.1%). Measurements on hydration kinetics, dimensional stability, compressive strength, and microstructural analyses like X-ray diffraction were conducted. Principal Component Analysis (PCA) was employed to interpret the continuous data derived from heat of hydration curves, length change curves and X-ray diffraction (XRD) patterns. Results indicated that retarder quantity and binder type significantly impacted paste workability. Higher powder content led to reduced strength, whereas increased accelerator improved strength. A strong correlation was observed between accelerator content and the dimensional stability. The primary hydration product’s formation was predominantly influenced by the PC-CAC-CŜ ratio, accelerator, and cement substitutions.

Mechanisms of CLDH seeding on hydration kinetics of slag-based geopolymer: Towards aluminosilicate cement phase engineering

The present investigation evaluates the feasibility of developing sustainable cementitious mortar by partially replacing ordinary Portland cement with a ternary eco-additive system consisting of microalgae biomass, fly ash, and MEL furnace slag. The motivation behind this research arises from the urgent requirement to reduce carbon emissions associated with cement production while simultaneously valorizing industrial and biological waste streams. Microalgae biomass contains calcium, silica, and bio-organic compounds that can act as nucleation sites and internal curing agents, whereas fly ash and furnace slag exhibit well-known pozzolanic and latent hydraulic behavior. The combined action of these materials is expected to enhance mechanical performance and durability while lowering environmental impact. Mortar mixes were prepared with varying replacement percentages (0–40%) of cement using algae powder, fly ash, and MEL furnace slag in different proportions. Fresh properties including flowability and water demand were assessed, followed by hardened properties such as compressive strength, flexural strength, density, and water absorption. Microstructural characteristics were interpreted based on hydration kinetics and bio-mineralization mechanisms. The study also evaluated durability behavior through sorptivity and permeability tests. Results demonstrated that the ternary system improves long-term strength and reduces pore connectivity due to secondary calcium silicate hydrate formation and bio-precipitation effects. The optimum performance was observed at 25–30% cement replacement where compressive strength exceeded the control mix after 28 and 56 days curing. The study confirms that algae-based mortar can function not only as a structural material but also as a carbon-sequestering composite due to biological mineralization. Fly ash contributes to delayed hydration strength while MEL furnace slag enhances early-age reaction. The integrated effect produces dense microstructure and improved durability characteristics. The research establishes the potential for producing low-carbon mortar suitable for masonry, plastering, and non-load-bearing structural components. This experimental investigation supports the development of circular construction materials and demonstrates a pathway for combining biological and industrial wastes into value-added construction products.

Hydration kinetics of a calcination activated bauxite tailings-lime-gypsum ternary system

Recycling metallurgical waste is essential for minimizing environmental impact and reducing industrial waste accumulation while conserving natural resources. Electric Arc Furnace (EAF) steel slag, a major byproduct of steel production, offers significant potential for reuse in composite materials intended for various applications. In this study, we explored the potential of EAF steel slag as a sustainable reinforcement material for epoxy‐based composites by integrating it with woven glass fibers in an epoxy matrix, contributing to the recycling of industrial waste and advancing the circular economy. The optimization of hot pressing conditions led to a maximum tensile strength of 263.74 MPa at 5 wt.% slag and a maximum flexural strength of 358.12 MPa at 10 wt.% slag, achieved under a hot pressing temperature of 50°C and a load of 50 kN. Thermal analysis showed that slag particle addition reduced heat flow but increased thermal decomposition. Moreover, the introduction of 30 wt.% EAF slag particles significantly improved X‐ray attenuation efficiency, achieving a maximum attenuation of 39.27% (150 kV) and 31.05% (250 kV), with Half‐Value Layer values of 1.39 cm at 150 kV and 1.86 cm at 250 kV. Using EAF slag for X‐ray shielding offers a sustainable approach to waste recycling and supports environmental sustainability goals.

The reclamation project at the Outer Harbor of Wollongong's Port Kembla, Australia, involves compaction of a large volume of granular fill material either under submerged or dry conditions. Due to environmental concerns (e.g. lack of suitable landfill space to dispose industrial wastes, conservation of natural resources etc) and the large volume reclamation project, Port Kembla Port Corporation is considering the use of locally abundant granular wastes of coal wash (CW) and steel furnace slag (SFS) as an alternative to conventional and costly fill materials. Although numerous studies have been reported on the geotechnical characterization of granular industrial wastes, only few information is available to comprehensively describe their compressive and mechanical behavior under submerged conditions. This paper reports on results of a series of unconfined compression strength (UCS) tests performed to investigate the effects of SFS content and curing time on the strength properties of underwater compacted mixtures of CW and SFS. For various mixtures kept submerged in seawater for a curing time of 7, 14 and 28 days, it was found that UCS strength properties increase with SFS content and

High plasticity clay soil is one of the soils that can be found in most regions of Iran. This soil is known as a problematic soil and as subgrade soil for transportation infrastructures, its characteristics must be improved. The purpose of this study is to evaluate the strength characteristics of high plasticity clay soil stabilized with industrial waste, which in addition to soil stabilization, also has environmental benefits. In this research, steel furnace slag, fly ash and diatomite have been used as stabilizer agents. Stabilization was performed using with 10, 20 and 30% of stabilizer agents by dry weight of soil and samples were compacted at optimum moisture content. In the present study, compaction as well as unconfined compressive strength (UCS) were conducted to compare the strength parameters of soil before and after stabilization. The results showed that the steel furnace slag had a much better performance as a stabilizer than fly ash and diatomite. Samples stabilized with 10% of steel furnace slag with a UCS of 2.16 MPa has a better performance in comparison with other stabilized samples and is the optimum sample. This sample shows a 3.92 times increase in UCS compared to the untreated clay soil. Treated samples with 30% of fly ash and 30% of diatomite with UCS of 0.9 and 1.03 MPa, show 49% and 88% increase in UCS compared to untreated samples, respectively.

Based on index properties in laboratory testing, foundry sand, and blast furnace steel slag may be considered as a construction backfill alternative. Naturally available granular materials for various fill applications are fast dwindling and sometimes not readily available near every construction site. In the current scenario, there is a substantial need to use alternative geomaterials. Many industry by-products and waste materials [fly ash, copper slag, bottom ash, construction, and demolition wastes (C&D), etc.] have been extensively studied for their suitability as a geomaterial. Steel slag generation in the world was estimated to be in the range of 170-250 MT in 2015, and considerable amounts of waste foundry sand are also generated. In the present study, waste foundry sand from Ordnance Factory, Medak, India, and blast furnace (BF) steel slag from Tata Steel, Jamshedpur, India, are tested for basic characteristics including gradation, specific gravity, morphology, chemical composition, and compaction. The engineering properties, shear strength, and permeability, are evaluated. In addition, leachate studies are conducted to assess the environmental impact of use of these materials for the proposed applications. Compaction behaviour of both the materials is found to be similar to granular soils. Foundry sand and BF steel slag exhibited an angle of shearing resistance of 31 0 and 37 0 , respectively. A comparative study on the properties of foundry sand and BF steel slag with the conventional fill material is performed, and the two waste products considered in the study are assessed for fill applications.