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Number of results: 8
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Abstract

This article presents the results of studies into the phase and chemical composition of blast furnace slag in the context of its reuse. In practice, blast furnace slags are widely used in the construction industry and road building as a basis for the production of, for example, cements, road binders and slag bricks. T hey are also used in the production of concrete floors, mortars, and plasters. Blast furnace slag is mainly used as a valuable material in the production of hydraulic binders, especially cement that improves the mechanical properties of concretes.
The favorable physical and mechanical properties of slags, apart from economic aspects, are undoubtedly an asset when deciding to use them instead of natural raw materials. In addition to the above, there is also the ecological aspect, since by using waste materials, the environmental interference that occurs during the opencast mining of natural aggregates is reduced. S pecifically, this means waste utilization through secondary management.
However, it should be kept in mind that it is a material which quite easily and quickly responds to environmental changes triggered by external factors; therefore, along with the determination of its physical and mechanical properties, its phase and chemical composition must be also checked.
The studies showed that the predominant component of the blast furnace slag is glass which can amount up to 80%. In its vicinity, metallic precipitate as well as crystallites of periclase, dicalcium silicates and quartz can be found. With regard to the chemical composition of the slag, it was concluded that it meets the environmental and technical requirements regarding unbound and hydraulically bound mixtures. In case of the latter, in terms of its chemical composition, the slag meets the hydraulic activity category CA3. It also meets the chemical requirements for using it as a valuable addition to mortars and concretes, and it is useful in the production of CEM II Portland-composite cement, CEM III blast-furnace cement and CEM V composite cements. The blast furnace slag is a valuable raw material for cement production. Cement CEM III/C contains 81–95% of blast furnace slag in accordance with E N 197-1:2012. In 2019, the Polish cement industry used 1,939,387.7 tons of slag.
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Authors and Affiliations

Iwona Jonczy
1
ORCID: ORCID
Bartłomiej Grzesik
2
ORCID: ORCID
Andrzej Norbert Wieczorek
1
Anna Gerle
3
Paweł Nuckowski
4
Marcin Staszuk
4
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Mining, Safety Engineering and Industrial Automation, Gliwice, Poland
  2. Silesian University of Technology, Faculty of Civil Engineering, Gliwice, Poland
  3. Łukasiewicz Research Network, Institute of Ceramics and Building Materials, Refractory Materials Division in Gliwice, Poland
  4. Silesian University of Technology, Faculty of Mechanical Engineering, Gliwice, Poland
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Abstract

This paper elucidated the potential of electron backscatter diffraction analysis for ground granulated blast furnace slag geopolymers at 1000°C heating temperature. The specimen was prepared through the mechanical ground with sandpaper and diamond pad before polished with diamond suspension. By using advanced technique electron backscatter diffraction, the microstructure analysis and elemental distribution were mapped. The details on the crystalline minerals, including gehlenite, mayenite, tobermorite and calcite were easily traced. Moreover, the experimental Kikuchi diffraction patterns were utilized to generate a self-consistent reference for the electron backscatter diffraction pattern matching. From the electron backscatter diffraction, the locally varying crystal orientation in slag geopolymers sample of monoclinic crystal observed in hedenbergite, orthorhombic crystal in tobermorite and hexagonal crystal in calcite at 1000°C heating temperature.
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Authors and Affiliations

Ikmal Hakem Aziz
1
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
2
ORCID: ORCID
Mohd Arif Anuar Mohd Salleh
2
ORCID: ORCID
Sorachon Yoriya
3
ORCID: ORCID
Rafiza Abd Razak
4
ORCID: ORCID
Rosnita Mohamed
1
ORCID: ORCID
Madalina Simona Baltatu
5
ORCID: ORCID

  1. Universiti Malaysia Perlis (UniMAP), Geopolymer & Green Technology, Centre of Excellence (CEGeoGTech), Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Perlis, Malaysia
  3. National Metal and Material Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114, Thailand Science Park, Pahonyothin Rd., Khlong 1, Khlong Luang, Pathum Thani 12120, Thailand
  4. Department of Civil Engineering Technology, Faculty of Engineering Technology, Universiti Malaysia Perlis (UniMAP), 02100 Padang Besar, Perlis, Malaysia
  5. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, 700050, Iasi, Romania
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Abstract

Blast furnace and cupola furnace are furnace aggregates used for pig iron and cast iron production. Both furnace aggregates work on very similar principles: they use coke as the fuel, charge goes from the top to down, the gases flow against it, etc. Their construction is very similar (cupola furnace is usually much smaller) and the structures of pig iron and cast iron are very similar too. Small differences between cast iron and pig iron are only in carbon and silicon content. The slags from blast furnace and cupola furnace are very similar in chemical composition, but blast furnace slag has a very widespread use in civil engineering, primarily in road construction, concrete and cement production, and in other industries, but the cupola furnace slag utilization is minimal. The contribution analyzes identical and different properties of both kinds of slags, and attempts to explain the differences in their uses. They are compared by the contribution of the blast furnace slag cooled in water and on air, and cupola furnace slag cooled on air and granulated in water. Their chemical composition, basicity, hydraulicity, melting temperature and surface were compared to explain the differences in their utilization.

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Authors and Affiliations

A. Pribulová
P. Futáš
J. Petrík
M. Pokusová
M. Brzeziński
J. Jakubski
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Abstract

This study explores the influence of alkali activators on the initiation of polymerization reaction of alumino-silicate minerals present in class-F fly ash material. Different types of fly ash aggregates were produced with silicate rich binders (bentonite and metakaolin) and the effect of alkali activators on the strength gain properties were analyzed. A comprehensive examination on its physical and mechanical properties of the various artificial fly ash aggregates has been carried out systematically. A pelletizer machine was fabricated in this study to produce aggregate pellets from fly ash. The efficiency and strength of pellets was improved by mixing fly ash with different binder materials such as ground granulated blast furnace slag (GGBS), metakaolin and bentonite. Further, the activation of fly ash binders was done using sodium hydroxide for improving its binding properties. Concrete mixes were designed and prepared with the different fly ash based aggregates containing different ingredients. Hardened concrete specimens after sufficient curing was tested for assessing the mechanical properties of different types concrete mixes. Test results indicated that fly ash -GGBS aggregates (30S2‒100) with alkali activator at 10M exhibited highest crushing strength containing of 22.81 MPa. Similarly, the concrete mix with 20% fly ash-GGBS based aggregate reported a highest compressive strength of 31.98 MPa. The fly ash based aggregates containing different binders was found to possess adequate engineering properties which can be suggested for moderate construction works.

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Authors and Affiliations

P. Gomathi
A. Sivakumar
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Abstract

The article analyzes the influence of selected factors on the activity rate of cement binder containing 50% of ground granulated blast furnace slag in its composition. These factors are the chemical and mineral composition of Portland cement CEM I, the degree of grinding of granulated blast furnace slag and Portland cement, and the water/binder ratio. This slag content is characteristic for blast furnace cement CEM III/A. In addition to the application effects, this type of cement is a low-carbon binder (there is a reduction of CO 2 emissions by about 45% compared to Portland cement CEM I). The use of this type of cement in the composition of concrete enables the obtaining of concrete with a very small carbon footprint. Based on the results of our own research, it was found that such a high proportion of ground granulated blast furnace slag in the binder composition leads to a significant reduction in the early compressive strength of standard mortars (after two and seven days of setting). This results in a significant reduction in the use of these types of binders (cements) in selected areas of construction, e.g. prefabrication and high-strength concrete. Analyzing the obtained results of their own research, the authors concluded that the early strength of these types of binders can be significantly improved by increasing the specific surface area (degree of grinding) of Portland cement CEM I and lowering the water/slag ratio (w/s, where: s = cement + slag). The proposed material and technological modifications also enable the obtaining of higher compressive strength at all tested dates. The strength of the standard (after twenty-eight days and over longer periods) is comparable to or higher than that of Portland cement CEM I.
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Authors and Affiliations

Arkadiusz Janic
1
ORCID: ORCID
Zbigniew Giergiczny
2
ORCID: ORCID

  1. Technology Centrum Betotech sp. z o.o., Dąbrowa Górnicza, Poland;
  2. Faculty of Civil Engineering Silesian University of Technology, Gliwice, Poland
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Abstract

The effects of supplementary cementitious materials (SCM) on the characteristics and internal structure of synthetic aggregate made from ground granulated blast furnace slag are investigated in this study (GGBS). Due to its high pozzolanic activity, GGBS was shown to be superior to other SCM materials, enhancing both the strength and durability of synthetic aggregate. Because sintering uses a lot of energy and generates a lot of pollutants, using a cold-bonded approach to make low density lightweight aggregates is particularly significant from an economic and environmental standpoint. Thus, the utilisation of ground granulated blast furnace slag (GGBS) as a substitute material in the production of green artificial lightweight aggregate (GLA) using the cold bonding method was discussed in this work. Admixtures of ADVA Cast 203 and Hydrogen Peroxide were utilised to improve the quality of GLA at various molar ratios. The freshly extracted GLA was then evaluated for specific gravity, water absorption, aggregate impact, and aggregate crushing in order to determine the optimal proportion blend. As a result, the overall findings offer great application potential in the development of concrete (GCLA). It has been determined that aggregates with a toughness of 14.6% and a hardness of 15.9% are robust. The compressive strength test found that the GCLA has a high strength lightweight concrete of 37.19 MPa and a density of 1845.74 kg/m3. The porous features developed inside the internal structure of GLA have led to GCLA’s less weight compared to conventional concrete.
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Authors and Affiliations

R.A. Razak
1 2
ORCID: ORCID
M.A. Hassan
1
ORCID: ORCID
M.M.A.B. Abdullah
2
ORCID: ORCID
Z. Yahya
1 2
ORCID: ORCID
M.A.M. Ariffin
3
ORCID: ORCID
A.F.B. Mansor
1
ORCID: ORCID
D.L.C. Hao
1 2
ORCID: ORCID

  1. Universiti Malaysia Perlis (UniMAP), Faculty of Civil Engineering Technology, Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Geopolymer & Green Technology, Centre of Excellence (CEGeoGTech), Perlis, Malaysia
  3. Universiti Teknologi Malaysia, School of Civil Engineering, Faculty of Engineering, Skudai, Johor Bahru, Malaysia
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Abstract

Iron production’s waste materials include significant quantities of blast furnace slag (BFS) which could potentially be used as a substitute for natural aggregates in hot mix asphalt (HMA) used in highway projects. Although many of properties of slag are interesting, its porosity and absorption rate would lead to greater consumption of asphalt. For this study, a Portland cement (PC) paste was used to reduce the porosity of a BFS. This PC treated BFS (called BFS-C) was then used in an HMA to replace the coarse fraction of a natural aggregate. Marshall, Indirect Tensile Strength (ITS), resilient modulus and Cantabro tests were then carried out on different HMA mixtures that included BFS-C. Using BFS-C, HMA’s resistance under monotonic loading, stiffness under cyclic loading, and resistance to moisture damage increased remarkably. In addition, the Cantabro abrasion resistance of BFS-C improved was better than that of the HMA mixture produced with untreated BFS.

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Authors and Affiliations

H.A. Rondón-Quintana
J.C. Ruge-Cardenas
J.G. Bastidas-Martínez
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Abstract

The properties of expansive concretes made of two types of cement: Portland cement CEM I and blast furnace slag cement CEM III were tested. The expansion of the concrete was caused by using an expansive admixture containing aluminium powder added in an amount of 0.5; 1 and 1.5% of cement mass. It was found that the compressive strength of concrete with CEM I decreased after using an expansive admixture in the amount of more than 0.5% of the cement mass. The compressive strength of concrete with CEM III decrease after addition of admixture in the entire range of dosages used. On the basis of electrochemical measurements, it was found no influence of an expansive admixture on corrosion of reinforcing steel. The use of an expansive admixture causes a slight increase in the effective diffusion coefficient of chloride ions in concrete.

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Authors and Affiliations

W. Jackiewicz-Rek
J. Kuziak
B. Jaworska

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