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Low-calcium (FA) and high-calcium (HCFA) fly ash and granulated blast furnace slag (GBFS) are the most widely known, standardized and used SCMs in the …
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Slag cement and fly ash are the two most common secondary cementatious materials used in concrete .Most concrete produced in nowadays includes one or multiple of these materials. That's why their properties are usually compared to each other by mix designers needed to optimize concrete mixtures. The present work a number of tests were carried ...
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The results indicate that lithium-slag and fly-ash can ameliorate the workability, setting time and improve the compressive strength of alkali-activated slag concrete,and when 40% or 60% slag ...
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2.1. The Process of Producing Recycled Aggregates (RA), Recycled Cement Mortar (RCM), and Fly–Ash Slag (FAS) The preparation of cement composites, due to the two types of waste used (fly–ash slag and concrete rubble), was based on two main types of treatment: (1) the process of producing recycled coarse aggregate (RCA) and recycled …
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Therefore, the binary alkali-activated fly ash/slag (AAFS) system can overcome the shortcomings of alkali-activated concrete based on a single precursor material and is more suitable for application in aggressive environments. ... Chloride ions in concrete generally exist in two forms: free chloride ions in the pore solution, and bound …
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Alkali-activated slag and fly ash (AASF) materials are emerging as promising alternatives to conventional Portland cement. Despite the superior mechanical properties of AASF materials, they are known to show large autogenous shrinkage, which hinders the wide application of these eco-friendly materials in infrastructure. To mitigate …
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Fly ash-based geopolymer concrete (FAGPC) presents a viable alternative to traditional Portland cement-based concrete for rural road construction. Unlike conventional concrete, which relies on Portland cement, FAGPC utilizes fly ash—a byproduct of coal combustion at power stations—as its primary binder. This shift results in a concrete with …
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The global warming potential of concrete is reduced by 22-30.6% and 44-51.4% when fly ash, regardless of type, is used at 25% and 50%, respectively, in comparison with pure cement concrete. High ...
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Aiming at the problems of long construction time and easy shrinkage cracking of pavement base, the slow-setting and expansive cement (SEC) was prepared using circulating fluidized bed ash and slag (CFBA and CFBS), S95 ground granulated blast furnace slag (GGBFS), and silica fume (SF) as supplementary cementitious material in this paper.
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Three types of cementitious materials are compared: OPC ( cement), slag-blended OPC (slag/cement mass ratio at 65/35) and alkali-activated slag/fly ash pastes (slag/fly ash mass ratio at 50/50).
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Both fly ash and slag can improve concrete's resistance to chloride attack [45], an important long-term durability attribute of concrete. Although fly ash and slag are considered avoided wastes [43, 46], certain processing and preparation of these materials may necessitate additional energy and emissions, which must also be quantified [45]. As ...
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Fly ash use in concrete improves the workability of plastic concrete, and the strength and durability of hardened concrete. Fly ash use is also cost effective. When fly ash is added to concrete, the amount of portland cement may be reduced. Benefits to Fresh Concrete. Generally, fly ash benefits fresh concrete by reducing the mixing …
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Another difference between slag and fly ash is that while fly ash will rarely surpass 35% of the cement content, slag can substitute 50% of the cement content, or even higher for different applications. This …
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First tests were performed on untreated clay soil, and its OMC, dry density, and UCS values were calculated. Then, clay sample was treated with fly ash + cement and fly ash + GGBS blends with 8, 12, 16, and 20%. Similarly, tests were done when clay then gets replaced by 50% of recycled aggregates.
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The fly ash is classified as Class F since its calcium oxide (CaO) content was 2.21% (<10%). The slag used in this study was classified as S105. The particle size distribution of slag and fly ash is presented in Fig. 1. River sand was chosen as the fine aggregate, with a maximum particle size of 4.7 mm and a fineness modulus of 2.91.
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Before we compare slag vs fly ash, let's first understand what they are. Slag is a byproduct that results from the smelting process of various ores, such as iron, copper, and lead. When these ores are heated to extract the desired metal, slag is formed as molten, which is later cooled and solidified. On the other hand, fly as…
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From those results, two main phases (C-AS -H and N-AS -H gels) are detected in slag/fly ash blended systems and with increase in fly ash content, the amount of the C-AS -H gel decreases and the ...
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This is because slag is easier to be activated compared with fly ash and more hydration products formed at lower value of CCFA/GBFS ratio. In the presence of OH − provided by activator, slag is dissolved, while Fly ash does not dissolve but decompose (Bijen, 1996). The dissolved slag and decomposed fly ash reacts with slaked lime to …
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This study investigated the influences of ultrafine fly ash (UFA) and ultrafine slag powder (USL) on the compressive strengths, autogenous shrinkage, phase assemblage, and microstructure of magnesium potassium phosphate cement (MKPC). The findings indicate that the aluminosilicate fractions present in both ultrafine fly ash and …
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Although slag and fly ash cement concrete are characterized as brittle composite materials, slag and fly ash exhibit a slower reaction rate in concrete compared to cement clinkers [11]. ... The images of the two sides of the specimens were taken after 3, 7, 14, and 28 cycles of healing. 3. Results and discussion3.1. Characterization of the HP
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Class C fly ash and a typical Class F fly ash. You will note that the GGBFS and the two fly ashes have the same kinds of oxides as the cement, which means that when GGBFS or …
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You will note that the GGBFS and the two fly ashes have the same kinds of oxides as the cement, which means that when GGBFS or fly ash is added to concrete, materials similar to Portland cement are being introduced into the system. Table 2: Slag Activity Index Requirements of ASTM C989 Chemical Constituents (as Oxides) Type I Cement Type …
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Slag cement and fly ash are the two most common SCMs used in concrete. Most concrete produced today includes one or both of these materials. For this reason their …
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Ground granulated blast furnace slag (GGBS) and fly ash (FA) are the two most often encountered aluminosilicate ingredients used when manufacturing geopolymer concrete (GPC).
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Fly ash can be separated into two main types, known as Class F and Class C. Class F fly ash contains particles covered in a type of melted glass allowing it to reduce the risk of concrete expansion and increase resistance to sulphates and alkali-aggregate reactions. ... In most situations, using fly ash cement instead of Portland cement to ...
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The Influence and Application of Slag, Fly Ash, and Limestone Flour on Compressive Strength of Concrete Based on the Concrete Compressive Strength Development Over Time (CCSDOT) Model
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The binder material used in the study was fly ash and slag. Fly ash is a byproduct of the combustion of coal, normally in the form of spherical particles . Slag, derived from blast furnace slag, is a byproduct of the ironmaking process . The utilized fly ash was Class II, F, with a sieve residue of 19.9% in the 45 μm sieve and a loss on ...
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In all mixtures, the mass ratio of fly ash to slag was kept constant equal to 1.0. The mass ratio of solid activator to geopolymer precursors (fly ash + slag) was also kept constant equal to 0.1. The water-to-geopolymer-solids ratio (W/GP-solids) of each mixture as defined by Hardjito et al. was also kept constant equal to 0.367. The mass …
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With cement being the costliest ingredient, substituting fly ash or slag can help maintain a stronger mix at a lower cost. Fly ash and Slag will typically be 18% cheaper than Portland cement. When a mix includes 20% fly …
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Fly ash has been widely used as a cement substitute to improve the sustainability of concrete. Although the advantages of fly ash have been extensively documented, there is a gap in understanding ...
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