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2.1. Materials. High calcium fly ash was used as the primary binder in this investigation. The chemical components of the high calcium fly ash used were detected by X-Ray fluorescence (XRF) and presented in Table 1.The fly ash was acquired from the Manjung Power Plant in Perak, Malaysia as a source of aluminosilicate materials for the production of one-part …
WhatsApp: +86 18221755073High-CaO fly ash is more highly reactive than low-CaO fly ash, probably because of its higher contents of highly active calcium aluminosilicate glass and crystalline compounds. …
WhatsApp: +86 18221755073Fly ash utilization, especially in concrete, has significant environmental benefits including: (1) increasing the life of concrete roads and structures by improving concrete …
WhatsApp: +86 18221755073A high-calcium fly ash (FH, 23% total CaO–5% free CaO), with high SO 3 content (4.3%), was studied as additive in mortar, replacing part of the volume either of Portland cement or aggregate. The development of the strength, porosity, bound water, and calcium hydroxide content was measured.
WhatsApp: +86 18221755073The strength increases with an increase in the curing time. A good strength of 48.5 ... This is rather unexpected as the literatures on the case of low calcium fly ash indicated that the high sodium silicate to NaOH ratio provided a higher compressive strength [4]. The variation in the ratio of sodium silicate to NaOH ratio affects the pH ...
WhatsApp: +86 18221755073This study investigated the performance of alkali-activated, cement-based controlled low-strength materials (CLSMs). The CLSM was produced by mixing fly ash, steel slag, sodium hydroxide, and ...
WhatsApp: +86 18221755073In this work, a study on a low cost and sustainable repair material made from alkali-activated high-calcium fly ash (FA) incorporated with calcium carbide residue (CCR) is reported. The FA was partially replaced with CCR (additional calcium source) at the dosages of 0%, 10%, 20%, and 30% by weight of binder.
WhatsApp: +86 18221755073shows a high early strength (Xie and Kayali, 2016). Fly ash is an aluminosilicate material that is widely used for the preparation of geopolymer composites, especially low-calcium fly ash (LCF)(NathandSarker,2017).Infact,oneofthemostimportantbenefits of using fly ash forgeopolymersynthesisis itseasyavailabilitycompared
WhatsApp: +86 18221755073The fly ash used in the study, which has very high-calcium (≈43%), has not good results for 10 M concentration. The compressive strength results and the microstructure images of the pastes support the results.
WhatsApp: +86 18221755073To expand the application range of magnesium oxysulfate cement (MOSC) and the utilization of fly ash, the water resistance of MOSC mixed with low-calcium fly ash (L-FA) or high-calcium fly ash (H ...
WhatsApp: +86 18221755073This work reports on an investigation of changes in physical and chemical properties of high calcium fly ash after recovering from the wet-stored conditions.
WhatsApp: +86 18221755073A subsequent Research Report GC3 covers the behaviour and strength of reinforced geopolymer concrete structural beams and columns.Heat-cured low-calcium fly ash-based geopolymer concrete has excellent compressive strength, suffers very little drying shrinkage and low creep, excellent resistance to sulfate attack, and good acid resistance.
WhatsApp: +86 18221755073Part II: a fundamental estimation of the efficiency factor. Cem Concr Res 2002;32(10):1533–8. [23] Antiohos S., Tsimas S. Investigating the role of reactive silica in the hydration mechanisms of high-calcium fly ash/cement systems. Cem. Concr. Comp. In press. [25] Papadakis VG. Effect of fly ash on Portland cement systems. Part II: high ...
WhatsApp: +86 18221755073For concrete containing high-calcium fly ash (FH, CaO more than 10%), the investigations are relatively insufficient. Due to the problems associated with the FH chemical …
WhatsApp: +86 18221755073The results of the XRF test are reported in Table 3.Both fly ash samples were found to be high calcium fly ash (class C), with total content of SiO 2 + Al 2 O 3 + Fe 2 O 3 of 67.8% and 66.29% for FA1 and FA2, respectively, and the CaO level of more than 10% and with a very low loss on ignition (LOI) value. FA2 has higher CaO content than FA1.
WhatsApp: +86 18221755073Read Setting Time, Strength, and Bond of High-Calcium Fly Ash Geopolymer Concrete ... low permeability, good chemical resistance, and excellent fire resistance. To study the sulfuric acid corrosion resistance of geopolymer concrete (GPC) with different binding materials and concentrations of sodium hydroxide solution (NaOH), metakaolin, high ...
WhatsApp: +86 18221755073The micromorphology of low-calcium fly ash and blast furnace slag is presented in Fig. 18. Low-calcium fly ash shows a complete spherical structure under SEM (Fig. 18 a), so fly ash can be used as an additive to improve the fluidity of concrete materials when preparing concrete. However, the spherical structure has a negative impact on concrete ...
WhatsApp: +86 18221755073For the preliminary study, using of high NaOH concentration (10 M) with high-calcium fly ash resulted in the fast setting of paste due to the reaction between NaOH and CaO. Therefore, lower NaOH concentration of 8 M was selected to overcome this problem and provide the more workability of paste.
WhatsApp: +86 18221755073High-calcium fly ash produced from low-temperature combustion of fuel, like in circulating fluidized bed technology, reacts with water readily and is itself a good hardening activator for GGBFS ...
WhatsApp: +86 18221755073This study presents the properties of a recycled aggregate geopolymer mortar made with a blend of high-calcium fly ash (HCF) and low-calcium fly ash (LCF). An experimental study was divided into two series. In series I, an effort was made to produce a more durable HCF geopolymer by partially replaci …
WhatsApp: +86 18221755073In this study, the effects of low-calcium fly ash (LFA) and high-calcium fly ash (HFA) on C–S–H structure, hydration products, hydration heat, and compressive strength of …
WhatsApp: +86 18221755073< 3.0 low good . 3.0 to 5 ... The results show that mortar and concrete made with portland cement-free activated fly ash develop a high mechanical strength in short periods of time, have a ...
WhatsApp: +86 18221755073An x-ray fluorescence (XRF) analysis may be used to determine the chemical composition of the fly ash. Low-calcium fly ash has been used successfully to manufacture geopolymer concrete for which the silicon and aluminum oxides constituted about 80% …
WhatsApp: +86 18221755073fly ash or high-calcium fly ash, as it typically contains more than 20 percent of C aO. On the other hand, fly ash from the bituminous a nd anthracite c o als is referred a s ASTM Class F fly ash ...
WhatsApp: +86 18221755073For high calcium fly ash, chemical and mineralogical differences have been observed for different size fractions. Compared to low calcium fly ash, optimum moisture content is low and …
WhatsApp: +86 18221755073The low cementitious capability in alkali-activated high-calcium fly ash may be attributed to the unstable N-C-A-S-H gel structure with concurrent high Na and Ca contents.
WhatsApp: +86 18221755073Evidence included in this investigation reveal that quicklime presence accelerated the reaction rate of high-calcium fly ash, whereas in the case of lower-calcium fly ash, quicklime had a …
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WhatsApp: +86 18221755073In this paper, we propose a novel mix design methodology for alkali-activated high-calcium fly ash concrete (AAHFAC) in a rational approach. It should be noted that the method is easy to use because it is based on the ACI …
WhatsApp: +86 18221755073The AA high-calcium FA has been used as an alternative repair material [16], [17], [18], [29] because of its fast setting and excellent mechanical properties. However, its strength is still lower than that of alkali-activated slag incorporated with low calcium FA [24].Many researchers have used the reactive CaO as additives for developing its strength when cured at …
WhatsApp: +86 18221755073Keywords: geopolymer; high-calcium fly ash; low-calcium fly ash; drying shrinkage; setting time. Abstract. N ew types of binders are b eing d eveloped as an alternative to traditional cement.
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