is it better to use high calcium fly ash in the mixing station or low calcium fly ash

A study on the synthesis and performance evaluation of fly …

Different supplementary cementitious materials (SCMs) like fly ash (FA), silica fume (SF), and slag are used to partially replace traditional raw materials like …

Fly ash for sustainable construction: A review of fly ash …

Fly ash makes concrete workable; increasing its levels may reduce water demand and superplasticizer needs. • Fly ash can improve mechanical and durability …

Alkali-activated aerated blends: interaction effect of slag with low …

Most of the studies adopted low-calcium Class-F fly ash as the binder, noticeably due to the negative effect of high calcium Class-C fly ash on the workability and setting time . Class-C Fly ash performed better when added in moderate rather than as a sole binder and performed well at lower (mostly ambient) curing temperature [12, 13].

The Influence of Fly Ash and Slag on the Mechanical …

The use of geopolymer as a cementitious material for geopolymer concrete (GPC) is beneficial for the sustainable development and green transformation of the …

A STUDY ON FACTORS AFFECTING …

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

Phase Analysis of Alkali-Activated Slag Hybridized with Low-Calcium …

This paper investigates the hydrated phase assemblage, microstructure, and gel composition of sodium hydroxide (NaOH)-activated fly ash–slag blends with either low-calcium or high-calcium fly ash. The results show that the nature of precipitated calcium–aluminosilicate–hydrate (C-A-S-H) and alkali aluminosilicate-hydrate (N-A-S …

Influence of fly ash on concrete – A systematic review

A mechanical mixer is used for mixing and vibrator for compaction. Super-plasticizer is used. 35%, 45%, and 55% of cement are replaced. w/c ratio of 0.4, 0.45 and 0.5 is used for each batch. ... the mechanical and physical properties of high calcium fly ash geopolymer concrete for pervious concrete is studied. The concrete comprises of …

Development of angular-shaped lightweight coarse aggregate with low

Low-calcium fly ash is the least commonly used fly ash among low and high-calcium fly ashes, owing to its lack of self-cementitious capabilities [4]. Producing environment-friendly fly ash aggregate using a sustainable and low-cost technique is the best solution to overcome the problems related to safe disposal of low-calcium fly ash …

The effects of calcium content of fly ash on hydration and

According to the difference in calcium content, fly ash is divided into high-calcium fly ash (C-class FA, abbreviated to HFA) and low-calcium fly ash (F-class FA, abbreviated to LFA) during actual engineering practice (Du et al., 2022). In general, HFA possessed higher reactivity than LFA in the hydration process of cement, which was …

A comprehensive review on the applications of coal fly ash

Coal fly ash is one of the most complex of the materials that can be characterized. Approximately 316 individual minerals and 188 mineral groups have been identified in various ash samples (Vassilev and Vassileva, 1997, Vassilev et al., 2003, Vassilev and Vassileva, 2005).The major components are metallic oxides with varying …

Suitability of heat-cured low-calcium fly ash-based …

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 ...

Alkali-Activated Controlled Low-Strength Material Utilizing High …

AbstractThis 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 water with bottom ash (BA) aggregate. Properties of ...

Materials | Free Full-Text | Experimental Investigation on …

The challenges of handling user-hostile alkaline solutions in the conventional alkali-activated binders (AAB) have initiated the development of "just add water" or one-part solid-based AAB systems. This paper aims to present a preliminary investigation on the development of one-part ambient-cured alkali-activated binders produced by …

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. ... (1–2% fly ash by weight) was added. After mixing, the geopolymer samples were left at ambient temperature for 1 h before heat curing ...

Characteristics and applications of fly ash as a sustainable

Fly ash is a man-made volcanic material. The definition of volcanic fly ash is "silicate or aluminosilicate material, which possesses weak or non-self-cementing ability, but in the finely divided state and damp environments at room temperature, it reacts with Ca(OH) 2 to form gel products" (Dunstan, 1989).There are many factors affecting the …

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 …

High-calcium fly ash recovery from wet-stored condition …

Evaluation of the material properties is considerably essential. This work reports on an investigation of changes in physical and chemical properties of high calcium fly ash after recovering from the wet-stored conditions. Herein the high calcium lignite fly ash with calcium oxide constituent in a range of 20%–30% is the focus of this study.

Drying shrinkage, strength and microstructure of alkali-activated high

This paper aims to investigate drying shrinkage, strength and microstructure of alkali-activated high-calcium fly ash (AAHF) paste by using FGD-gypsum (FGD) and dolomite (DLM) as expansive additives. The 10 M sodium hydroxide combined with sodium silicate solutions were used as alkaline activator for all mixes. …

Chapter 3

The use of fly ash in portland cement concrete (PCC) has many benefits and improves concrete performance in both the fresh and hardened state. 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.

Influence of low calcium fly ash on compressive strength and hydration

On the other hand, the feature of FTIR for CFA indicated the mostly presences of anhydrite (CaSO 4) and portlandite (Ca(OH) 2) transformed from the reaction of free lime (f-CaO) and vaporized water in air [22, 23].Indeed, the information of CaSO 4 detected in FTIR spectrum of the CFA included a strong band centered around 1138 cm …

Flexural Behavior of Low Calcium Fly Ash Based …

The main parameters affecting the fly ash geo-polymer mixtures are the content of cilium, concentrations of alkaline solutions, and curing method. In GPC, the low calcium fly ash is preferred because high calcium poses the risk of flash setting before casting the elements (Antoni et al., 2020).

Synthesis of high strength ambient cured geopolymer composite by using

In this work, low-calcium fly ash, treated by a wet-grinding process, named wet-grinding ultrafine fly ash (WUFA) was used as an Al supplement to replace some of the phosphorus slag, and the wet ...

Strength Characteristics of Low Calcium Fly Ash Based …

Based on the mixture design process eighty one test cubes of 150x150x150mm of low-calcium fly ash-based geopolymer concrete were cast to study the effect of various parameters on compressive strength of low-calcium fly ash-based geopolymer concrete. Keywords: - Geopolymer concrete, Characteristic strength, Fly ash, Superplasticizer. I. …

Stabilization of Soft Clay by a Low-Calcium Fly Ash …

The current study investigated the stabilization efficacy of low-calcium fly ash (FA) geopolymer for soft clay. The influence of FA content, initial water content, and curing time on stabilization efficacy was investigated. ... The results indicated that the mechanical performance of the soft clay at high water content was greatly improved by ...

Effect of High-Speed Mixing on Properties of High …

This research studied the effect of mixing when used a high-speed mixer (1,000rpm) at various mixing time on the setting time, compressive strength, mineral composition, …

A review on fly ash utilization

Bond coat of NiCr was deposited on the steel substrate prior to fly ash coatings alone. Fly ash coated specimens shown micro hardness of 1100 HV compared to that of 230 HV of uncoated specimen. From the study, it is also evident that improvement in thermal wear resistance of tested steel samples at 1500 °C by using fly ash-based …

Fly Ash

Sometimes fly ashes may also contain many small spherical particles within a large glassy sphere, called pherospheres. The exterior surfaces of the solid and hollow spherical particles of low-calcium oxide fly ashes are generally smooth and better defined than those of high-calcium oxide fly ashes which may have surface coatings of …

Effect of High-Speed Mixing on Properties of High Calcium …

This research studies the effects of mixing time, with a high-speed centrifuge mixer (1,000 rpm), on the setting and hardening properties of high calcium fly ash …

Fly Ash Pollutants, Treatment and Recycling | SpringerLink

3.2.1 Coal Fly Ash. Coal FA is a predominantly inorganic residue obtained from the flue gases of furnaces at pulverised coal power plants. When coal is burnt, the minerals entrained in the coal are thermally transformed into chemical species that are reactive or could be chemically activated, for example, by the addition of calcium …

Review A review on fly ash high-value synthesis utilization …

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 …