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

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3307 ◽  
Author(s):  
Jinyan Liu ◽  
Cheng Yi ◽  
Hongguang Zhu ◽  
Hongqiang Ma
Keyword(s):  
Stainless Steel ◽  
Blast Furnace ◽  
Activated Carbon ◽  
Carbon Steel ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Stainless Steel Slag ◽  
Solid Ratio ◽  
Furnace Slag ◽  
Alkali Activated

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.

scholarly journals Concrete Properties Comparison When Substituting a 25% Cement with Slag from Different Provenances

2018 ◽  
Author(s):  
María Eugenia Parrón-Rubio ◽  
María Dolores Rubio-Cintas ◽  
Francisca Pérez-García ◽  
Antonio Gonzalez-Herrera
Keyword(s):  
Blast Furnace ◽  
Environmental Sustainability ◽  
Blast Furnace Slag ◽  
Construction Material ◽  
Steel Slag ◽  
High Energy ◽  
Stainless Steel Slag ◽  
Concrete Properties ◽  
Furnace Slag ◽  
By Products

Concrete consumption greatly exceeds the use of any other material in engineering. This is due to its good properties as construction material and the availability of its components. Nevertheless, the present worldwide construction increase and the high-energy consumption for cement production means a high environmental impact. On the other hand, one of the main problem in iron and steel industry is waste generation and by-products that must be properly processed or reused to promote the environmental sustainability. One of these by-products are blast furnace slag. Cement substitution by slag strategy achieves two goals, raw materials consumption reduction and waste management. In the present work, four different concrete mixtures are evaluated. 25% cement is substituted by different blast furnace slag. Tests are made to evaluate the advantages and drawbacks of each mixture. Depending on the origin, characteristics and treatment of the slag, concrete properties change. Certain mixtures provide proper concrete properties. Stainless steel slag produces a fluent mortar that reduces the water consumption whit a slight mechanical strength loss. Mixture with electric arc slag furnace properties are better to the reference concrete (without slag) when slag is treated similarly to the cement.

scholarly journals Compressive Strength and Microstructure Properties of Alkali-Activated Systems with Blast Furnace Slag, Desulfurization Slag, and Gypsum

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Bong-Suk Cho ◽  
Kyung-Mo Koo ◽  
Se-Jin Choi
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Construction Material ◽  
Steel Slag ◽  
Steel Production ◽  
Value Added ◽  
Cement Industry ◽  
Furnace Slag ◽  
Alkali Activated

This study investigates the effect of desulfurization slag (DS) and gypsum (G) on the compressive strength and microstructure properties of blast furnace slag-(BFS-) based alkali-activated systems. DS is produced in a Kambara reactor process of molten iron produced in a steel production process. DS contains CaO, SiO2, Fe2O3, and SO3 and is composed of Ca(OH)2 and 2CaO·SiO2 as main compounds. In this investigation, the weight of BFS was replaced by DS at 5, 10, 15, 20, 25, and 30%. In addition, G was also applied at 9, 12, and 15% by weight of BFS to improve the compressive strength of the alkali-activated system with BFS and DS. According to this investigation, the compressive strength of the alkali-activated mixes with BFS and DS ranged from 14.9 MPa (B95D5) to 19.8 MPa (B90D10) after 91 days. However, the 28 days compressive strength of the alkali-activated mixes with BFS, DS, and G reached 39.1 MPa, 45.2 MPa, and 48.4 MPa, respectively, which were approximately 78.8 to 97.5% of that of O100 mix (49.6 MPa). The main hydrates of the BFS-DS (B80D20) binder sample were Ca(OH)2, CaCO3, and low-crystalline calcium silicate hydrates, while the main hydration product of BFS-DS-G (B75D10G15) binder was found as ettringite. The use of BFS-DS-G binders would result in the value-added utilization of steel slag and provide an environmentally friendly construction material, and contribute to a reduction of CO2 in the cement industry.

scholarly journals Influence of Steel Slag-Superfine Blast Furnace Slag Composite Mineral Admixture on the Properties of Mortar and Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhenguo Liu ◽  
Zongxian Huang
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Autogenous Shrinkage ◽  
Mineral Admixture ◽  
Strength Development ◽  
Adiabatic Temperature Rise ◽  
Solid Ratio ◽  
Composite Mixture ◽  
Furnace Slag

A composite mineral admixture was prepared by steel slag and superfine blast furnace slag. The influence of superfine blast furnace slag content of the composite mixture on the mortar and concrete was investigated. The results show that the composite mineral admixture may decrease the strength of concrete at the early age but improve the strength development over time. Increasing the content of superfine blast furnace slag can reduce the degradation of the early strength. The reduction of the autogenous shrinkage and adiabatic temperature rise is significant when the composite mineral admixture is added. The reduction is more obvious when the water-to-solid ratio (w/s) is low. The results show that with steel slag and superfine blast furnace slag playing as complementary parts in the composite mineral admixture, it can be used as an effective substitute of cement.

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