scholarly journals Properties and Hydration Mechanism of Soda Residue-Activated Ground Granulated Blast Furnace Slag Cementitious Materials

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2883
Author(s):  
Yonghui Lin ◽  
Dongqiang Xu ◽  
Xianhui Zhao
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Industrial Solid Waste ◽  
Hydration Mechanism ◽  
Granulated Blast Furnace Slag ◽  
Free Chloride ◽  
Furnace Slag

Soda residue (SR), an industrial solid waste, pollutes the environment due to its high alkalinity and chloride ion content. SR can be used as an alkali activator of ground granulated blast furnace slag (GGBFS). This study investigated the effects of four types of SR-activated GGBFS cementitious materials (pastes) with different mass ratios of SR to GGBFS (8:92, 16:84, 24:76, 34:68) on the physical properties, mechanical strength, and chloride binding capacity. The hydration mechanism of the pastes was also studied. Results showed that with the increasing addition of SR, the density of the pastes decreased, and more white aggregates of SR appeared causing the increase of water absorption and porosity of the pastes. The pastes with 16% SR addition had the maximum compressive strength (34.1 MPa, 28 d), so the optimum proportion of SR addition in the pastes was 16%. With the increases of SR addition, the amount of chloride element in the initial pastes increases. When the proportion of SR addition is 8%, the mass percentage of free chloride ion in the pastes at 28 d is 0.13%. The main hydration products of the pastes were C–S–H gels, ettringite, and Friedel’s salt, and the amount of ettringite varied with the amount of SR addition and curing time.

scholarly journals Synergistic Excitation Mechanism of CaO-SiO2-Al2O3-SO3 Quaternary Active Cementitious System

2021 ◽  
Vol 8 ◽  
Author(s):  
Fusheng Niu ◽  
Yukun An ◽  
Jinxia Zhang ◽  
Wen Chen ◽  
Shengtao He
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Test Block ◽  
Hydration Reaction ◽  
Alkaline Environment ◽  
Granulated Blast Furnace Slag ◽  
Cementitious System ◽  
Furnace Slag

In this study, the influence of steel slag (SS) content on the strength of the cementitious materials was investigated. The quaternary active cementitious material (CaO-SiO2-Al2O3-SO3) was prepared using various proportions of steel slag (SS), granulated blast furnace slag (BFS), and desulfurized gypsum (DG). The mechanism of synergistic excitation hydration of the cementitious materials was examined using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The strength of the mortar test block was initially increased and decreased later with the increase of the SS content. Mortar test block with 20% steel slag, 65% granulated blast furnace slag, and 15% desulfurized gypsum with 0.35 water-binder ratio showed the highest compressive strength of 57.3 MPa on 28 days. The free calcium oxide (f-CaO) in the SS reacted with water and produced calcium hydroxide (Ca(OH)2) which created an alkaline environment. Under the alkaline environment, the alkali-activated reaction occurred with BFS. In the early stage of hydration reaction, calcium silicate hydrate (C-S-H) gel and fibrous hydration product ettringite (AFt) crystals were formed, which provided early strength to the cementitious materials. As the hydration reaction progressed, the interlocked growth of C-S-H gel and AFt crystals continued and promoted the increase of the strength of the cementitious system.

scholarly journals Characterization of Supplementary Cementitious Materials and Fibers to Be Implemented in High Temperature Concretes for Thermal Energy Storage (TES) Application

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5190
Author(s):  
Laura Boquera ◽  
David Pons ◽  
Ana Inés Fernández ◽  
Luisa F. Cabeza
Keyword(s):  
Tensile Strength ◽  
Blast Furnace ◽  
High Temperature ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Iron Silicate ◽  
Supplementary Cementitious Materials ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Six supplementary cementitious materials (SCMs) were identified to be incorporated in concrete exposed to high-temperature cycling conditions within the thermal energy storage literature. The selected SCMs are bauxite, chamotte, ground granulated blast furnace slag, iron silicate, silica fume, and steel slag. A microstructural characterization was carried out through an optical microscope, X-ray diffraction analysis, and FT-IR. Also, a pozzolanic test was performed to study the reaction of SCMs silico-aluminous components. The formation of calcium silica hydrate was observed in all SCMs pozzolanic test. Steel slag, iron silicate, and ground granulated blast furnace slag required further milling to enhance cement reaction. Moreover, the tensile strength of three fibers (polypropylene, steel, and glass fibers) was tested after exposure to an alkalinity environment at ambient temperature during one and three months. Results show an alkaline environment entails a tensile strength decrease in polypropylene and steel fibers, leading to corrosion in the later ones.

scholarly journals Performa Beton Dengan Ground Granulated Blast Furnace Slag Terhadap Sulfate Attack

2020 ◽  
Vol 16 (3) ◽  
pp. 185
Author(s):  
Rizki Amalia Tri Cahyani ◽  
Ernawan Setyono ◽  
Yunan Rusdianto
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Cementitious Materials ◽  
Sulfate Attack ◽  
Supplementary Cementitious Materials ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Serangan sulfat (sulfate attack) termasuk hal yang umum terjadi pada struktur beton, mengingat ion sulfat banyak dijumpai pada tanah, air tanah dan air laut. Peningkatan ketahanan beton melawan sulfat akan berdampak besar pada durabilitas dan umur layan struktur beton. Penambahan supplementary cementitious materials seperti GGBFS (ground granulated blast furnace slag) ke campuran beton telah terbukti memberikan pengaruh positif terhadap durabilitas dan properti mekanis beton. Namun, GGBFS tergolong material yang baru dikembangkan di Indonesia dan potensinya dalam meningkatkan durabilitas beton belum dimanfaatkan secara luas. Berdasarkan hal tersebut, perlu dilakukan investigasi terkait aplikasi GGBFS dan pengaruhnya terhadap durabilitas beton, terutama dalam melawan serangan sulfat. Dalam studi ini, durabilitas beton dengan persentase penggantian GGBFS 30%, 50% dan 70% terhadap total volume binder dievaluasi menggunakan perlakuan siklus basah-kering dalam larutan magnesium sulfat. Tingkat degradasi beton diukur dengan melakukan observasi terhadap perubahan kuat tekan dan massa spesimen akibat serangan sulfat. Hasil penelitian menunjukkan bahwa penggantian GGBFS hingga 50% dari total volume binder dapat meningkatkan ketahanan beton terhadap serangan sulfat, ditunjukkan dengan kehilangan massa dan reduksi kekuatan yang lebih rendah dibandingkan spesimen kontrol dengan 100% semen Portland.

scholarly journals Comparative Study on Chloride Binding Capacity of Cement-Fly Ash System and Cement-Ground Granulated Blast Furnace Slag System with Diethanol-Isopropanolamine

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4103
Author(s):  
Huaqing Liu ◽  
Yan Zhang ◽  
Jialong Liu ◽  
Zixia Feng ◽  
Sen Kong
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binding Capacity ◽  
Slag System ◽  
Chloride Binding ◽  
Chemical Binding ◽  
Granulated Blast Furnace Slag ◽  
Steel Bar ◽  
Furnace Slag

Steel bar corrosion caused by chloride was one of the main forms of concrete deterioration. The promotion of chloride binding capacity of cementitious materials would hinder the chloride transport to the surface of steel bar, thereby alleviating the corrosion and mitigating the deterioration. A comparative study on binding capacity of chloride in cement-fly ash system (C-FA) and cement-ground granulated blast furnace slag system (C-GGBS) with diethanol-isopropanolamine (DEIPA) was investigated in this study. Chloride ions was introduced by adding NaCl in paste, and the chloride binding capacity of the paste samples at 7 d and 60 d was examined. The hydration process was discussed via the testing of hydration heat and compressive strength. The hydrates in hardened paste was characterized by X-ray Diffractometry (XRD), Thermo Gravimetric Analysis (TGA), and Scanning Electron Microscope (SEM). The effect of DEIPA on dissolution of aluminate phase and compressive strength was discussed as well. These results showed that DEIPA could facilitate the hydration of C-FA and C-GGBS system, and the promotion effect was higher in C-FA than that in C-GGBS. DEIPA also increased the binding capacity of chloride in C-FA and C-GGBS systems. One reason was the increased chemical binding, because DEIPA facilitated the dissolution of aluminate to benefit the formation of Friedel’s salt. Other reasons were the increased physical binding and migration resistance. By contrast, DEIPA presented greater ability to increase chloride binding capacity in C-FA system, because DEIPA showed stronger ability to expedite the dissolution of aluminate of FA than that of GGBS, which benefited the formation of FS, thereby promoting the chemical binding. Such results would give deep insight into using DEIPA as an additive in cement-based materials.

Durability of Normal and Lightweight Aggregate Mortars with Different Supplementary Cementitious Materials

2021 ◽  
Vol 17 ◽  
pp. 271-281
Author(s):  
Efstratios Badogiannis ◽  
Eirhnh Makrinou ◽  
Marianna Fount
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Granulated Blast Furnace Slag ◽  
Binder Ratio ◽  
Pumice Sand ◽  
Water To Binder Ratio ◽  
Furnace Slag

A study on the durability parameters of normal and lightweight aggregate mortars, incorporated different supplementary cementitious materials (SCM) is presented. Mortars were prepared using limestone or pumice as aggregates and Metakaolin, Fly ash, Granulated Blast Furnace Slag and Silica Fume, as SCM, that they replaced cement, at 10 % by mass. Ten different mortars, having same water to binder ratio and aggregate to cement volumetric ratio, they were compared mainly in terms of durability. The use of pumice sand was proved to be effective not only to the density of the mortars as it was expected, but also in durability, fulfilling at the same time minimum strength requirements. The addition of the different SCM further enhanced the durability of the mortars, where Metakaolin was found to be the most effective one, especially against chloride’s ingress.

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