Optimization design and characterization of slag cementitious composites containing carbide slag and desulfurized gypsum based on response surface methodology

Ji, Xin; Wang, Zhenjun; Huo, Jinyang; Zhang, Tonghuan

doi:10.1016/j.jobe.2023.107441

Cited by 8 publications

(5 citation statements)

References 48 publications

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“…The Ca-O, Si-O-Si and Al-O-Al bonds break and react to form silicate monomers and aluminum monomers ( Figure 14 b; Equations (3)–(5)) [ 40 , 41 ]. Subsequently, silicate monomers and aluminum monomers react with calcium or sodium ions to form C(N)-A-S-H gel; calcium ions react with OH − to form C-H gel ( Figure 14 c; Equations (6)–(8)) [ 42 , 43 ]. Furthermore, the disruption of the calcium, silicon and aluminum phases provides a gateway for the alkali activators to enter the interior of the bonded particles, whereby the bonded particles are continuously activated and reaction products are generated ( Figure 14 d).…”

Section: Resultsmentioning

confidence: 99%

Properties, Microstructure Development and Life Cycle Assessment of Alkali-Activated Materials Containing Steel Slag under Different Alkali Equivalents

Ji,

Wang,

Zhao

et al. 2023

Materials

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To improve solid waste resource utilization and environmental sustainability, an alkali-activated material (AAM) was prepared using steel slag (SS), fly ash, blast furnace slag and alkali activators in this work. The evolutions of SS content (10–50%) and alkali equivalent (4.0–8.0%) on workability, mechanical strength and environmental indicators of the AAM were investigated. Furthermore, scanning electron microscopy, X-ray diffraction and nuclear magnetic resonance techniques were adopted to characterize micromorphology, reaction products and pore structure, and the reaction mechanism was summarized. Results showed that the paste fluidity and setting time gradually increased with the increase in SS content. The highest compressive strength was obtained for the paste at 8.0% alkali equivalent due to the improved reaction rate and process, but it also increased the risk of cracking. However, SS was able to exert a microaggregate filling effect, where SS particles filling the pores increased the structural compactness and hindered crack development. Based on the optimal compressive strength, global warming, abiotic resource depletion, acidification and eutrophication potential of the paste are reduced by 76.7%, 53.0%, 51.6%, and 48.9%, respectively, compared with cement. This work is beneficial to further improve the utilization of solid waste resources and expand the application of environmentally friendly AAMs in the field of construction engineering.

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Section: Resultsmentioning

confidence: 99%

Properties, Microstructure Development and Life Cycle Assessment of Alkali-Activated Materials Containing Steel Slag under Different Alkali Equivalents

Ji,

Wang,

Zhao

et al. 2023

Materials

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“…The Box-Behnken experimental design is a commonly used trial design method in response surface optimization, providing a multi-factor, three-level experimental design and its analysis. This method uses a multi-variable quadratic equation to fit the functional relationship between factors and response values, and seeks the optimal process parameters through the analysis of the regression equation to solve multi-variable problems [14,19].…”

Section: Optimization Of Mechanical Properties By Response Surface Me...mentioning

confidence: 99%

“…Response surface methodology involves the construction of a nonlinear model to achieve a high-precision regression equation. This method comprehensively considers the interactions between various factors and determines the optimal ratio through reasonable predictions [14]. The mechanical properties of alkali-activated steel slag-slag cementitious materials are influenced by multiple indices such as the main material content, alkali content, and water glass modulus.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Performance Optimization and Microstructural Mechanism Study of Alkali-Activated Steel Slag–Slag Cementitious Materials

Wang,

Xu,

Zhang

et al. 2024

Buildings

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The optimal proportion of alkali-activated steel slag–slag cementitious materials is investigated by considering the combined effects of steel slag content, alkali content, water glass modulus, and water–binder ratio using the Box–Behnken design in response surface methodology. Qualitative and semi-quantitative analyses of X-ray diffraction (XRD) patterns and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) images are conducted. The microstructural mechanism is elucidated based on the chemical composition, surface morphology, and microscale pore (crack) structures of the samples. A microreaction model for the alkali-activated steel slag and slag is proposed. The optimal composition for alkali-activated steel slag–slag cementitious materials is as follows: steel slag content, 38.60%; alkali content, 6.35%; water glass modulus, 1.23; and water–binder ratio, 0.48. The strength values predicted by the response surface model are p1d = 32.66 MPa, p7d = 50.46 MPa, and p28d = 56.87 MPa. XRD analysis confirms that the compressive strength of the sample is not only influenced by the amount of gel formed, but also, to a certain extent, by the CaCO3 crystals present in the steel slag, which act as nucleation sites. The SEM-EDS results confirm that the gel phase within the system comprises a hydrated calcium silicate gel formed through the reaction of volcanic ash and geopolymer gel formed through geo-polymerization. Analysis of the pore (crack) structure reveals that the compressive strength of the specimens is primarily influenced by porosity, with a secondary influence of the pore fractal dimension.

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“…The strength of the specimen improved, owing to the ability of EMR and CS to fill the pores and enhance the density of the mortar [28]. Additionally, the sulfate phase in EMR and the free alkali substances in CS effectively stimulated the hydration activity of GBFS, leading to the generation of more hydration products [29,30].…”

Section: Compressive Strengthmentioning

confidence: 99%

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

Liang,

Liu,

Jing

et al. 2024

Applied Sciences

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Industrial solid waste is characterized by complex mineral phases and various components. Low-carbon cementitious materials can be prepared through precise regulation based on the material composition and properties of various industrial solid wastes. In this study, electrolytic manganese residue (EMR), carbide slag (CS), and granulated blast-furnace slag (GBFS) were used as alternatives to cement to prepare multicomponent solid waste cementitious materials. The effects of the proportions of EMR and CS on the cementitious activity of GBFS and the activation mechanism of alkali and sulfur were studied. The results showed that with increasing EMR content, the strength first increased and then decreased. At a GBFS content of 20%, CS content of 2%, and EMR content of 8%, the compressive strength was highest, reaching 45.5 MPa after 28 days of curing, mainly because the OH− in CS and SO42− in EMR synergistically stimulated the active components in GBFS. Hydrated products such as ettringite and hydrated calcium silicate (C–S–H gel) were generated and interlaced with each other to improve the densification of the mortar. Overall, the proposed system provides an avenue to reduce or replace the production of cement clinker and achieve the high-value-added utilization of industrial solid waste.

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Optimization design and characterization of slag cementitious composites containing carbide slag and desulfurized gypsum based on response surface methodology

Cited by 8 publications

References 48 publications

Properties, Microstructure Development and Life Cycle Assessment of Alkali-Activated Materials Containing Steel Slag under Different Alkali Equivalents

Properties, Microstructure Development and Life Cycle Assessment of Alkali-Activated Materials Containing Steel Slag under Different Alkali Equivalents

Mechanical Performance Optimization and Microstructural Mechanism Study of Alkali-Activated Steel Slag–Slag Cementitious Materials

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

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