Microstructure and phase evolution of alkali-activated steel slag during early age

Ze, Liu; Zhang, Dawang; Li, Li; Wang, Jixiang; Shao, Ningning; Wang, Dongmin

doi:10.1016/j.conbuildmat.2019.01.213

Cited by 94 publications

(31 citation statements)

References 29 publications

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“…erefore, on the basis of changing the curing method, the aforementioned deficiencies can be addressed by using fine materials, such as an admixture, a cementitious material, or a fine aggregate, such as silica fume, fly ash, steel slag, or tailings. Fine materials can not only improve the early performance of cement-based materials but also contribute to green development through the reuse of solid waste and reduction in the consumption of construction raw materials [20][21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Combined Effects of Graphite Tailings and Curing Conditions on the Early-Age Performances of Cement Mortar

Liu

Zhang

et al. 2020

Advances in Civil Engineering

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In this study, the combined effects of different amounts of graphite tailings (GT) as a substitute for sand and three cure methods on the early-age mechanical and material performances of cement mortar have been investigated. The results can be concluded that graphite tailings and hot-water cure method can effectively improve the early strength of cement-based materials and facilitate the formation of high-density calcium silicate hydrate (C-S-H), more Ca(OH)2 (CH), and other hydration products. Simultaneously, the pore structure distribution in the cement mortar is improved to be finer. Finally, this paper explains the mechanism of GT and hot-water curing (HWC) method on early-age performances of the cement mortar through the graphic model and provides the basis for selecting the GT and HWC method on improving early performance requirements for special engineering or rapid repair engineering through the proposed comprehensive quantitative calculation model.

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Section: Introductionmentioning

confidence: 99%

Combined Effects of Graphite Tailings and Curing Conditions on the Early-Age Performances of Cement Mortar

Liu

Zhang

et al. 2020

Advances in Civil Engineering

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“…Currently, steel slag is used mostly for low value-added applications, including asphalt concrete aggregates, fillers for foundation engineering, supplementary cementitious materials, etc. [1,2,11,12,13,14,15]. This necessitates substantial piling up of steel slag, which causes environmental pollution, arable land occupation and resource wastage.…”

Section: Introductionmentioning

confidence: 99%

“…The methods of steel slag activation mainly include thermal activation [16,17,18], mechanical activation [19,20], chemical activation [9,12,18,21] and steel slag reconstruction [22,23], of which alkali activation is undoubtedly the current hot topic. Alkali activated materials (AAMs) are a class of cementitious materials formed by reacting pozzolanic or latently hydraulic materials like fly ash (FA), blast furnace slag (BFS) and metakaolin with alkaline activators.…”

Section: Introductionmentioning

confidence: 99%

“…Alkali activated materials (AAMs) are a class of cementitious materials formed by reacting pozzolanic or latently hydraulic materials like fly ash (FA), blast furnace slag (BFS) and metakaolin with alkaline activators. They have received widespread scholarly attention owing to their prominent physical properties such as high strength, high corrosion resistance, fire resistance, hazardous waste sealability, as well as the advantage of efficient industrial residue utilization [12,24,25,26,27]. On the other hand, alkali-activated materials have large drying shrinkage and poor toughness, which can cause cracking of paste, mortar or concrete, thus restricting their development [28,29,30,31].…”

Section: Introductionmentioning

confidence: 99%

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Property Comparison of Alkali-Activated Carbon Steel Slag (CSS) and Stainless Steel Slag (SSS) and Role of Blast Furnace Slag (BFS) Chemical Composition

et al. 2019

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In order to compare the properties of alkali-activated carbon steel slag (CSS) and stainless steel slag (SSS), the effects of sodium hydroxide/sodium silicate solution mass ratio (NH/NS), liquid/solid ratio and blast furnace slag (BFS) dosage on the compressive strength, hydration products and hydration degree of CSS and SSS were studied. Furthermore, a combination of X-ray diffraction (XRD), thermo-gravimetric analysis coupled with differential thermal analysis (TGA-DTA), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) were used to characterize the morphology and structure of alkali-activated CSS-BFS and SSS-BFS cementitious materials. As the results revealed, the primary hydrate of alkali-activated CSS and SSS is C-(A)-S-H with Q2 [SiO4] units, which has a low Ca/Si ratio and includes inert phases like a CaO-FeO-MnO-MgO solid solution (RO) in CSS while cuspidine, magnesiochromite etc. in SSS. More active C3S and β-C2S promote the alkali activation of CSS, whereas the less active γ-C2S hinders the depolymerization of SSS. The incorporation of BFS does not change the hydrate, whose seed effect is helpful for accelerating the depolymerization and polycondensation of CSS and SSS, especially for SSS, and makes the hydrate increase significantly. Owing to the high SiO2 and Al2O3 contents of SSS, the C-(A)-S-H chain length is increased, thus facilitating the polycondensation effect. In this study, the optimal NH/NS of CSS and SSS is NH/NS= 1:2, and the optimal liquid/solid ratio is 0.29. Compared to CSS–BFS, the C-(A)-S-H gel produced by SSS–BFS has lower Ca/Si and Al/Si ratios. Unlike CSS, pure SSS is inappropriate as an alkali-activated precursor and needs to be co-activated with BFS.

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“…In this regard, AAM has become a novel candidate for developing inorganic coatings for architectural decorating.The construction process of decorative coatings requires good plastic formable capacity ensuring the coating is flexibly formed into a complex layer appearance so that it meets people's aesthetic expectations, which highly relates to the plastic viscosity and thixotropy. Few papers have investigated the relationship between different alkaline activators and solid particles on the rheological behavior of AAM [20][21][22], but studies have found that AAM often shows the excellent fluidity due to the high electrostatic repulsion of the particle surface which was caused by the fast diffusion rate of the Al and Si elements in high content [OH] − [22,23]. Furthermore, there is no colloidal interaction or flocculation structure between AAM particles, and lots of residua water is present in aluminosilicates particles in a freely moving status which does not take part in reaction [20,23].…”

mentioning

confidence: 99%

One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

Qin

Lin

et al. 2020

Molecules

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Coating technology can be applied to decorate building constructions. Alkali-activated materials (AAM) are promising green and durable inorganic binders which show potential for development as innovative coating. In the paper, the possibility of using AAM composited with starch (CMS) as a novel plastic formable inorganic coating for decorating in building was investigated. The rheological properties, including plastic viscosity, yield stress, and thixotropy were considered to be critical properties to obtain the working requirements. Four different mixtures were systematically investigated to obtain the optimum formulation, and then were used to study their hardened properties, such as mechanical strengths (compressive, flexural, and adhesive strength), drying shrinkage, cracking behavior, and microstructure. Study results found that CMS could quickly and efficiently be hydrolyzed in an alkaline solution to produce organic plastic gel which filled in AAM paste, leading to the significant improvement of coating consistency, plastic viscosity, and thixotropy. The optimum coating composited with 15.40 wt% CMS shows a relatively stable rheological development, the setting time sufficient at higher than 4 h. Furthermore, CMS shows a significant positive effect on the cracking and shrinkage control due to padding effect and water retention of CMS, which results in no visible cracks on the coating surface. Although the mechanical strength development is relatively lower than that of plain AAM, its value, adhesive strength 2.11 MPa, compressive strength 55.09 MPa, and flexural strength 8.06 MPa highly meet the requirements of a relevant standard.

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Microstructure and phase evolution of alkali-activated steel slag during early age

Cited by 94 publications

References 29 publications

Combined Effects of Graphite Tailings and Curing Conditions on the Early-Age Performances of Cement Mortar

Combined Effects of Graphite Tailings and Curing Conditions on the Early-Age Performances of Cement Mortar

Property Comparison of Alkali-Activated Carbon Steel Slag (CSS) and Stainless Steel Slag (SSS) and Role of Blast Furnace Slag (BFS) Chemical Composition

One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

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