scholarly journals Effect of Ammonia-Soda Residue on the Strength and Chloride-Resistance Performance of Steel Slag-Granulated Blast Furnace Slag-Based Concrete after Immersion in Artificial Seawater

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6048
Author(s):  
Chengwen Xu ◽  
Wen Ni ◽  
Keqing Li
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Chloride Ions ◽  
Artificial Seawater ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Friedel’S Salt ◽  
Chloride Resistance ◽  
Furnace Slag

Ammonia-soda residue (ASR) is the main solid waste generated from soda manufacturing and is hard to reuse due to its complex chemical composition. This study investigated the influence of ASR content on the strength and chloride-resistance capacity of concrete based on basic oxygen furnace slag and ground blast furnace slag. The hydration and chloride resistance mechanisms were analysed by comparing the hydrate products and pore structural changes. The results showed that adding ASR had the greatest impact on early strength. ASR-introduced chloride ions may participate in the hydration process to generate Friedel’s salt and decrease ettringite. The optimum pore distribution appeared when the ASR-to-desulphurisation gypsum ratio was 2:3 because of the introduction of nucleation sites and the decrease of C–S–H gels. The two chloride resistance-capacity measurements were affected differently by the ASR content. The apparent chloride diffusion coefficient was mainly affected by the percentage of pores that were larger than 10 nm. However, electric flux increased when ASR increased due to the influence of introduced chloride. The crystallisation pressure of Friedel’s salt decreases the strength of concrete with ASR content after high-concentration artificial-seawater immersion. The significant chloride-resistance property provided an alternative use for the concrete containing ASR.

scholarly journals EFFECTS OF BLAST FURNACE SLAG ON CHLORIDE PERMEABILITY OF CONCRETE

2012 ◽  
Vol 15 (2) ◽  
pp. 70-80
Author(s):  
Mien Van Tran ◽  
Yen Thi Hai Nguyen ◽  
Thi Nguyen Cao
Keyword(s):  
Diffusion Coefficient ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binding Capacity ◽  
Concrete Strength ◽  
Steel Reinforcement ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Chloride Permeability ◽  
Furnace Slag

Chloride-induced corrosion of steel reinforcement is the main cause of deterioration of reinforced concrete structures in marine environments. The penetration of chlodride ions into concrete cover that accelerates corrosion process of steel reinforcement, this affects the bearing capacity of structures. This paper investigates on chloride permeability cheracteristic of concrete using blast furnace slag in terms of chloride diffusion coefficient and chloride binding capacity. The concrete used in this research has grade of 45MPa and the slag content replacement of cement PC50 is in range of 0% - 70%. The chloride diffusion coefficient of concrete is determined by ASTM C1202 and NordTest NT Build 492. Results showed that the blast furnace slag replacement increases (from 0% to 50%), the chloride ion diffusion coeffient decreases and bound chloride content in concrete increases. It is clear to conclude that blast furnace slag can be used to replace cement PC50 in range of 30% to 40% in order to increase the resistance of concrete to chloride penetration without affecting concrete strength.

scholarly journals Engineering Properties of Ternary Cementless Blended Materials

2020 ◽  
Vol 10 (3) ◽  
pp. 191-199
Author(s):  
Wei-Ting Lin ◽  
Kinga Korniejenko ◽  
Marek Hebda ◽  
Michał Łach ◽  
Janusz Mikuła
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Engineering Properties ◽  
Chloride Diffusion ◽  
Total Charge ◽  
Chloride Diffusion Coefficient ◽  
Furnace Slag

A new non-cement blended materials is developed as a full replacement of cement without alkali activator. This study was conducted to explore a suitable method for activating new ternary green materials with desulfurization gypsum, water-quenched blast-furnace slag and co-fired fly ash from circulating fluidized bed combustion as non-cement inorganic binder. Test subject was included flowability, compressive strength, absorption, total charge-passed from rapid chloride permeability test, chloride diffusion coefficient from accelerated chloride migration test and SEM observation. Test results indicate that a ternary mixture containing 1% desulfurization gypsum, 60% water-quenched blast-furnace slag and 39% co-fired fly ash was a suitable development in compressive strength. The new non-cement blended materials were performed a well compressive strength, lower absorption, and lower chloride diffusion coefficient. In addition, the compressive strength decreased as the inclusion of desulfurization gypsum increased. It was concluded that using desulfurization gypsum alone decreased the setting time and compressive strength. SEM micrographs were verified the development in compressive strength originated from the C-S-H and C-A-S-H gel produced by Ca(OH)2, SiO2, and Al2O3.

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.

Study on Sulfate Resistance of Concrete with Compound Mineral Admixture

2011 ◽  
Vol 99-100 ◽  
pp. 420-425 ◽  
Author(s):  
Qian Rong Yang ◽  
Xiao Qian Wang ◽  
Hui Ji
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Sulfate Attack ◽  
Mineral Admixture ◽  
Sulfate Resistance ◽  
Chemical Attack ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The strength, expansion and amount of scaling of concrete with compound mineral admixture (CMA) from steel slag, granulated blast furnace slag and fly ash were studied. The result shows that damage by crystallization press from sulfate attack when concrete was exposed to sulfate environments under wetting–drying alternation is much larger than that from sulfate chemical attack. Adding CMA to concrete could reduce the damage from expansion of concrete caused by sulfate chemical attack, but the resistance of concrete to damage by crystallization press from sulfate attack was remarkably reduced.

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