Setting Time, Strength, and Bond of High-Calcium Fly Ash …
AbstractIn this paper, setting time, strength and bond of high-calcium fly ash geopolymer concrete were investigated. The high-calcium fly ash was from Mae Moh power plant in northern Thailand. Both sodium silicate solution and sodium hydroxide solution ...
اقرأ أكثر
Calcium wastes as an additive for a low calcium fly ash …
Class F or low-calcium fly ash (LCFA) is generally used as a primary aluminosilicate source; however, heat curing is required to complete the reaction and …
اقرأ أكثر
(PDF) Development and Properties of Low-calcium Fly Ash …
fly 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 ...
اقرأ أكثر
Transforming MSWI fly ash into low-carbon and high …
Transforming MSWI fly ash into low-carbon and high-compatibility composites via designed calcium sulfoaluminate-based binders ... (MSWI FA) is a globally recognized hazardous waste. This study developed a low-carbon and high-compatibility calcium sulfoaluminate-enhanced ternary binders (PCG) composed of calcium sulfoaluminate cement, ordinary ...
اقرأ أكثر
Calcium wastes as an additive for a low calcium fly ash …
High-calcium fly ash (HCFA) from the lignite PCC process of the Mae Moh power plant complied with Class C coal ash specifications and was used for comparison. The minimum combined content of SiO 2, Al 2 O 3, and Fe 2 O 3 of 50% was detected for the Class C fly ash, with a high calcium content of 31.0 wt%.
اقرأ أكثر
Characteristics of Waste Iron Powder as a Fine Filler in a High-Calcium …
For 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.
اقرأ أكثر
Effect of fly ash on Portland cement systems
A high-calcium fly ash (FH, 23% total CaO–5% free CaO), with high SO3 content (4.3%), was studied as additive in mortar, replacing part of the volume either of Portland cement or aggregate.
اقرأ أكثر
Durability Study on High Calcium Fly Ash Based …
The high content of fly ash underwent less geopolymerization and less hydration associated with the calcium as compared to those of less amount of fly ash as indicated by the strength results . Figures 11 and 12 show the density and compressive strength of OPC.
اقرأ أكثر
Evaluation of the Chemical and Mechanical Properties of …
For 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 compositions (high …
اقرأ أكثر
Properties of high-calcium fly ash-based geopolymer …
The 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.
اقرأ أكثر
Dry Mix Slag—High-Calcium Fly Ash Binder. Part One: …
High-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 ...
اقرأ أكثر
Strength, durability, and heat development characteristics of …
High-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. …
اقرأ أكثر
Workability and strength of coarse high calcium fly ash geopolymer
The 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 ...
اقرأ أكثر
Dynamic properties of PVA short fiber reinforced low-calcium fly ash
The 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 ...
اقرأ أكثر
Effects of low- and high-calcium fly ash on magnesium …
In this paper, the performance of MOSC with low-calcium fly ash (L-FA) and high-calcium fly ash (H-FA) was investigated, including the setting times, compressive strengths, shrinkages, compositions and microstructures. The results show that adding FA to MOSC can accelerate the hydration reaction and improve the volume stability of the MOSC paste.
اقرأ أكثر
Effect of fly ash on Portland cement systems: Part II. High-calcium fly …
A 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.
اقرأ أكثر
Geotechnical Properties of Low Calcium and High Calcium Fly Ash …
In this paper, a comparative study has been made for physical and engineering properties of low calcium and high calcium Indian fly ash. The grain size distribution of fly ash is independent of lime content. Fly ash particles of size >75 μm are mostly irregular in shape whereas finer fractions are spherical for low calcium fly ash. For high calcium fly ash, chemical and mineralogical ...
اقرأ أكثر
(PDF) High-calcium fly ash recovery from wet-stored
215 phase in the high calcium class C fly ash is considerably more reactive than that in the low calcium fly 216 ash. [57] Such amorphous form of calcium compound is usually the main constituent ...
اقرأ أكثر
Properties of high-calcium and low-calcium fly ash …
This 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 …
اقرأ أكثر
Enhancing Compressive Strength of Very High Volume Fly Ash …
Fly ash integrates well with cement, demonstrating favorable qualities in concrete such as good workability, high ultimate strength, and durability. ... The pozzolanic reaction of low-calcium fly ash in mixtures activated at 20 °C and 60 °C using 0.14 M NaOH leads to a significant increase in compressive strength at an early age, ...
اقرأ أكثر
Properties of high-calcium and low-calcium fly ash …
The main purpose of the research was to examine the processing possibilities of a low-grade high Ca fly ash (FA) to increase its future utilisation potential.
اقرأ أكثر
Influences of the Ratios of High-Calcium Fly Ash …
The influence of calcium compounds (CaO and Ca(OH)(2)) on the mechanical properties of fly ash based geopolymers has been studied. Calcium compounds were substituted in fly ash at 1, 2 and...
اقرأ أكثر
Evaluation of blends of high and low calcium fly ashes for …
Evaluation of blends of high and low calcium fly ashes for use as supplementary cementing materials ... The fly ash mixtures present good early-age k-values and at 90 days they all exceed the corresponding values of the initial ashes used. It is of special importance to note that the k-value of the blend consisting of equal contributions from ...
اقرأ أكثر
Geotechnical Properties of Low Calcium and High Calcium …
For 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 …
اقرأ أكثر
Comparative mechanical and microstructural properties of high calcium …
The higher compressive strength achieved by OPG synthesised in this study is because of the lower water content in this mix system and the high CaO content in the fly ash used that was able to yield calcium-containing hydrate gel, which was compact and contributed to a better mechanical properties [27]. The finding of this study suggests that ...
اقرأ أكثر
Properties of high-calcium and low-calcium fly ash …
shows 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
اقرأ أكثر
Microstructural Analysis of Low-Calcium Fly Ash-Based …
Geopolymer concretes have emerged as an alternative to traditional Portland cement concretes with high strength, good durability, well corrosion performance and high-temperature resistance, and being a sustainable and environmentally friendly material. In this study, a comprehensive microstructural analysis of low-calcium fly ash-based geopolymer …
اقرأ أكثر
Low cost and sustainable repair material made from alkali …
The 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 …
اقرأ أكثر
Mechanical and microstructural properties of high calcium fly ash …
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 …
اقرأ أكثر
High calcium cementless fly ash binder with low
Hwang and Shahsavari (2019) investigated the optimization of a high calcium cementless fly ash (FA) binder with a low environmental footprint. Their optimized composition comprising of FA and ...
اقرأ أكثر