Is It Better To Use High Calcium Fly Ash In The Mixing Station Or Low Calcium Fly Ash

By mixing fly ash with other materials, such as cement, sand, and water, a strong and durable concrete can be produced. ... The specific gravity can range from as low as 1.90 for …

According to ASTM C618, a fly ash with at least 18 % CaO is classified as a high-CaO fly ash. A fly ash with less than 18 % Cao is classified as a low-CaO fly ash or Class F fly ash. Theoretically, high-calcium fly ash produced from the combustion of subbituminous or lignite coal has cementing or self-hardening properties [24].

The current study investigates the suitability of low-calcium fly ash (FA) for stabilizing expansive soil using the in-situ deep soil mixing (DSM) technique.

Further, using lime and cement for the soil treatment can result in better improvement but at a high cost (Indiramma et al., 2020, Inkham et al., 2019, Rasmussen et al., 2018, Renjith et al., 2021).Therefore, using FA waste materials as additives in the soil is a more economical alternative for many stabilisation applications than any other additives.

Based on its calcium content, FA can be classified into low-calcium FA (LFA), typically containing less than 10 % calcium oxide (CaO), and high-calcium FA (HFA) [5]. LFA is commonly used in the construction industry as an SCM in concrete mixtures due to its capability to enhance workability, increase long-term strength, and improve durability [7] .

This paper discusses the advantages of using low-calcium fly ash (FA)-based geopolymer concrete (GPC) for precast applications when high early-age strength is required. Heat curing is known to be ...

The carbonation resistance of a blended slag and low-calcium fly ash (FA) geopolymer concrete was investigated. The geopolymer binder studied was composed of 90% low-calcium FA and 10% ground ...

Owing to the presence of a low amount of calcium oxide (CaO) in Class-F fly ash (FA), an alkali environment is required to produce pozzolanic reactions involvingsilica and alumina.

Low and high calcium based fly ash stockpiles, classified according to the ASTM standard C 618 [8] as class F when the content of SiO 2 + Al 2 O 3 + Fe 2 O 3 is greater than 70 wt.% of the total composition of the ash, and class C if the content of SiO 2 + Al 2 O 3 + Fe 2 O 3 is between 50 wt.% and 70 wt.%, can be used for production of geopolymer concretes, …

A well-developed understanding of the use of fly-ash-based and slag-based geopolymers as separate systems has been reached in the literature, specifically regarding their mechanical properties.

DEVELOPMENT AND PROPERTIES OF LOW-CALCIUM FLY ASH-BASED GEOPOLYMER CONCRETE By D. Hardjito and B. V. Rangan Research Report GC 1 Faculty of Engineering Curtin University of Technology Perth, Australia 2005 PREFACE From 2001, we have conducted some important research on the development, manufacture, behaviour, and applications of …

In 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 …

Instead, activating the source materials such as fly ash that are rich in Silicon (Si) and Aluminium (Al) using high alkaline liquids produces the binder required to manufacture the concrete ...

This concrete uses no Portland cement; instead, we use the low-calcium fly ash from a local coal burning power station as a source material to make the binder necessary to manufacture concrete.

As a common industrial solid waste, fly ash requires proper processing and utilization to alleviate environmental pressure. In contrast to earlier low-value treatment methods for fly ash, such as its use in construction materials, it is more practical to explore the high-value utilization of fly ash, considering its elemental ingredient and morphological characteristics.

The low-calcium class-F fly ash-based geopolymer has a high setting time, which can be reduced significantly by using heat curing [25,41] or by adding GGBFS [25,29]. Evaluating the parameters that influence the setting time of these types of geopolymer is essential to control the setting duration and reach a setting that meets the desired time.

Thus, high calcium fly ash is suitable as source materials for making good geopolymer. Proper mixing of initial raw materials is a very important step in any chemical synthesis process. It has …

Their availability, however, varies locally, and several other materials are being researched, based on local availability, such as high calcium fly ash (HCFA), metakaolin, ladle furnace slag (LFS), and rice husk ash . The present research investigates the use of HCFA, a by-product of lignite-fired power plants; LFS, a by-product of the ...

Curtin Research Report on Fly Ash-Based Geopolymer Concrete Develoment and properties of low-calcium fly ash-based geopolymer concrete by Djwantoro Hardjito and B.Vijaya Rangan Research Report GC 1 (103 pages) (dec. 2005), Report GC 2 (107 pages) (mar. 2006) Faculty of Engineering, Curtin University of Technology Perth, Australia

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.

This study investigates the suitability of low-calcium fly ash (FA) for stabilizing expansive soil (ES) using the in-situ deep soil mixing (DSM) technique. The primary objective of the study was to control the swell-shrink behavior of ES and achieve ... The growing use of blends of low- and high-calcium solid precursors in combination with ...

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%.

The durability of SC-mortar has increased with increasing fly ash content, and there was an exceptional increment in water ingression time (T25) with an increase in fly ash content from 25% to 35% ...

Therefore, it appears that the use of Low Calcium (ASTM Class F) fly ash is more preferable than High Calcium (ASTM Class C) fly ash as a source material to make geopolymers. 7 Swanepoel and Strydom (2002), Phair and Van Deventer (2001; 2002), Van Jaarsveld (2002a; 2002b) and Bakharev (2005a; 2005b; 2005c) also presented studies on fly ash as ...

Low calcium fly ash samples were collected from two different coal -powered facilities: an Indonesian fertilizer plant and a Japanese power plant. Several series of tests were conducted using various

LOW-CALCIUM FLY ASH-BASED GEOPOLYMER CONCRETE: LONG-TERM PROPERTIES By S. E. Wallah and B. V. Rangan Research Report GC 2 Faculty of Engineering Curtin University of Technology Perth, Australia 2006 PREFACE From 2001, we have conducted some important research on the development, manufacture, behaviour, and applications of Low-Calcium Fly …

Overall, the use of HVFA mixtures would be ideal for warm weather placements; when compared with the TDOT Class A mixtures, the HVFA mixtures exhibit comparable costs, increased …

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.

In the content of this study it was shown that intermixtures of high and low calcium fly ashes results in an effective, environmental friendly and relatively cheap cementitious …

The high strength geopolymer paste could also be obtained with the use of fine fly ash [32]. In this study, the fly ash used was an as-received one and was rather coarse with the Blaine fineness of 2250 cm 2 /g. However, it was illustrated that the rather coarse high-calcium fly ash geopolymer could be used to produce pervious concrete with ...