Alkali-Activated EAF Reducing Slag as Binder for Concrete

2013 ◽  
Vol 723 ◽  
pp. 580-587
Author(s):  
Wen Huan Zhong ◽  
Tung Hsuan Lu ◽  
Wei Hsing Huang
Keyword(s):  
Portland Cement ◽  
Drying Shrinkage ◽  
Portland Cement Concrete ◽  
Steel Making ◽  
Chemical Content ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated ◽  
Better Than

Electric arc furnace (EAF) reducing slag is the by-product of EAF steel-making. Currently, reducing slag is considered a waste material by the industry in Taiwan. Since the chemical content of reducing slag is similar to blast furnace slag (BFS), it is expected that reducing slag exhibits a similar pozzolanic effect as the BFS. This study used alkaline activator consisting of sodium silicate and sodium hydroxide to improve the activity of reductive slag so as to replace Portland cement as binder in concrete. Some BFS was used to blend with the reducing slag to enhance the binding quality of alkali-activated mixes. The results show that a blend of 50% BFS and 50% reducing slag can be activated successively with alkali. Also, the sulfate resistance of concrete made with alkali-activated EAF reducing slag is found to be better than that of concrete made with portland cement, while the drying shrinkage of alkali-activated EAF reducing slag concrete is greater than that of portland cement concrete.

Review on Alkali-Activated Fly Ash Based Geopolymer Concrete

2016 ◽  
Vol 841 ◽  
pp. 162-169 ◽  
Author(s):  
Kefiyalew Zerfu ◽  
Januarti Jaya Ekaputri
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Construction Material ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Carbon Credit ◽  
Cement Concrete ◽  
Carbon Dioxide Co2 ◽  
Alkali Activated ◽  
Better Than

Due to environmental pollution form cement industries, some efforts for alternative construction material are increasing. Recently, geopolymer concrete has drawn attention of researchers and engineers because of its lower carbon print and better mechanical property over Portland cement concrete. According to previous studies, geopolymer concrete results almost up to 90% reduction in carbon dioxide (CO2) emission to atmosphere. Mechanical properties of geopolymer concrete such as compressive strength, durability, sulfate resistance, early strength and low shrinkage are better than Portland cement concrete. In addition, the appropriate usage of one ton of fly ash earns one carbon-credit redemption value of about 20 Euros, and hence earned monetary benefits through carbon-credit trade.Therefore, this paper presents a review on the fly ash-based geopolymer concrete. The paper mainly covers composition, mixing and curing process, benefits, limitations and applications of alkali activated fly ash based geopolymer concrete.

scholarly journals Synthesis of Ambient Cured GGBFS Based Alkali Activated Binder Using a Sole Alkaline Activator: A Feasibility Study

2021 ◽  
Vol 11 (13) ◽  
pp. 5887
Author(s):  
Thandiwe Sithole ◽  
Nelson Tsotetsi ◽  
Tebogo Mashifana
Keyword(s):  
Silicate Solution ◽  
Environmental Footprint ◽  
Ambient Temperatures ◽  
Granulated Blast Furnace Slag ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Porous Morphology ◽  
Furnace Slag ◽  
Alkali Activated

Utilisation of industrial waste-based material to develop a novel binding material as an alternative to Ordinary Portland Cement (OPC) has attracted growing attention recently to reduce or eliminate the environmental footprint associated with OPC. This paper presents an experimental study on the synthesis and evaluation of alkali activated Ground granulated blast furnace slag (GGBFS) composite using a NaOH solution as an alkaline activator without addition of silicate solution. Different NaOH concentrations were used to produce varied GGBFS based alkali activated composites that were evaluated for Uncofined Compressive Strength (UCS), durability, leachability, and microstructural performance. Alkali activated GGBFS composite prepared with 15 M NaOH solution at 15% L/S ratio achieved a UCS of 61.43 MPa cured for 90 days at ambient temperatures. The microstructural results revealed the formation of zeolites, with dense and non-porous morphology. Alkali activated GGBFS based composites can be synthesized using a sole alkaline activator with potential to reduce CO2 emission. The metal leaching tests revealed that there are no potential environmental pollution threats posed by the synthesized alkali activated GGBFS composites for long-term use.

Effects of over Heat and Casting Speed on Quality of GCr15 Billet

2014 ◽  
Vol 997 ◽  
pp. 534-537 ◽  
Author(s):  
Qi Wei Zuo ◽  
Xia An ◽  
Jing Bo Yang ◽  
Da Qiang Cang
Keyword(s):  
Casting Speed ◽  
The Other ◽  
Steel Making ◽  
Average Grade ◽  
Upset Forging ◽  
C 30 ◽  
Better Than ◽  
Center Porosity

In order to improve the quality of the billets, the whole test proceedings by the comparison of the two casting conditions which one is over heat 20°C-30°C under casting speed 0.4m/min-0.6m/min and the other is over heat 10°C-15 °C under casting speed 1.3m/min-1.6m/min are checked during the produce process of GCr15 in some domestic steel-making plant. The results show that the average grade of general porosity decreases 1.0, the average grade of center porosity down 0.5, the average grade of center segregation fall 0.5 and the samples tested in hot upset forging perform better than before. According to the results, the latter is determined to be accepted.

scholarly journals Microstructure Features of Ternary Alkali-activated Binder Based on Tungsten Mining Waste, Slag and Metakaolin

2020 ◽  
Author(s):  
Naim Sedira ◽  
João Castro-Gomes
Keyword(s):  
Sodium Silicate ◽  
Room Temperature ◽  
Mining Waste ◽  
Dense Matrix ◽  
Microstructural Properties ◽  
Reaction Products ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This study determines the effect of ground granulated blast furnace slag (GGBFS) and metakaolin (MK) on the microstructural properties of the tungsten mining waste-based alkali-activated binder (TMWM). During this investigation, TMWM was partially replaced with 10 wt.% GGBFS and 10 wt.% MK to improve the microstructure of the binder. In order to understand the effect of the substitutions on the microstructure, two pastes were produced to make a comparative study between the sample contain 100% TMWM and the ternary precursors. Both precursors were activated using a combination of alkaline activator solutions (sodium silicate and sodium hydroxide) with the ratio of 1:3 (66.6 wt.% sodium silicate combined with 33.33 wt.% of NaOH 8M). The alkali-activated mixes were cured in oven at temperature of 60 °C in the first day and at room temperature for the next 27 days. The reaction products N-A-S-H gel and (N,M)-A-S-H gel resulted from the alkaline activation reaction process. In addition, a formation of natrite (Na2CO3) with needles shape occurred as a reaction product of the fluorescence phenomena. However, a dense matrix resulted from the alkline activation of the ternary precursors containg different gels such as N-A-S-H, C-A-S-H and (N,M)-C-A-S-H gel, these results were obtained through SEM-EDS analyses, as well FTIR tests. Keywords: Mining Waste, Alkali-activated, Microstructure, Slag, Metakaolin

scholarly journals Geopolymer Based on Mechanically Activated Air-cooled Blast Furnace Slag

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1134 ◽  
Author(s):  
Ilda Tole ◽  
Magdalena Rajczakowska ◽  
Abeer Humad ◽  
Ankit Kothari ◽  
Andrzej Cwirzen
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Portland Cement ◽  
Sodium Silicate ◽  
Blast Furnace Slag ◽  
Ball Mill ◽  
Efficient Solution ◽  
Building Materials ◽  
Furnace Slag ◽  
Alkali Activated

An efficient solution to increase the sustainability of building materials is to replace Portland cement with alkali-activated materials (AAM). Precursors for those systems are often based on water-cooled ground granulated blast furnace slags (GGBFS). Quenching of blast furnace slag can be done also by air but in that case, the final product is crystalline and with a very low reactivity. The present study aimed to evaluate the cementitious properties of a mechanically activated (MCA) air-cooled blast furnace slag (ACBFS) used as a precursor in sodium silicate alkali-activated systems. The unreactive ACBFS was processed in a planetary ball mill and its cementing performances were compared with an alkali-activated water-cooled GGBFS. Mixes based on mechanically activated ACBFS reached the 7-days compressive strength of 35 MPa and the 28-days compressive strength 45 MPa. The GGBFS-based samples showed generally higher compressive strength values.

EXPLORATORY STUDY ON THE MECHANICAL AND PHYSICAL PROPERTIES OF CONCRETE CONTAINING SULFUR

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
David Yeoh ◽  
Koh Heng Boon ◽  
Norwati Jamaluddin
Keyword(s):  
Portland Cement ◽  
Physical Properties ◽  
Ordinary Portland Cement ◽  
Cement Content ◽  
Drying Shrinkage ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Complete Replacement ◽  
Mechanical And Physical Properties ◽  
Ordinary Portland Cement Concrete

This research is an exploratory experiment into sulfur concrete used not as a complete replacement of cement but as an additional material in percentage of the cement content. The aim of this research was to explore the possible appreciation of mechanical and physical properties of concrete containing sulfur with percentages of 1%, 5% and 10% of the cement content. The sulfur used here was not heat-activated, hence the binding effect in sulfur was absent. The experimental results revealed that concrete containing sulfur did not perform better in their strength properties, both compressive strength and flexural strength. The physical properties such as water penetration and water absorption for concrete containing sulfur also showed poor performance in comparison to ordinary Portland cement concrete. Such phenomena are very likely due to the sulfur not being activated by heat. Carbonation test did not show good results as a longer term of testing is required. Drying shrinkage property was found to be encouraging in that concrete containing 10% sulfur had quite significant reduction in drying shrinkage as opposed to ordinary Portland cement concrete. 

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