Can High Calcium Fly Ash Concrete Be Used

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Utilization of High Calcium Content Fly Ash: Flexural …

This paper presents the study of flexural strength of geopolymer concrete beam using high calcium content fly ash in marine environment, without high heat curing. From test results after 28 days of curing, it can be concluded that sea water has almost no effect on compressive and splitting tensile strength of fly ash-based geopolymer concrete.

Prediction of Scaling Resistance of Concrete Modified with High-calcium

Keywords: high calcium ï¬‚y ash, freeze-thaw resistance, scaling resistance, machine learning, classiï¬ ca- tion, durability prediction 1 Introduction The application of high calcium ï¬‚y ash (HCFA) for partial replacement of Portland cement in concrete could provide a number of environmental beneï¬ ts (reduced CO2 emissions during ...

Factors Affecting the Workability and Strength of Alkali-Activated High

The mechanical properties like compressive strength, split tensile strength, flexural strength of activated fly ash concrete and flexural strength of activated fly ash reinforced concrete beams are studied. For this project work, the chemicals like sodium silicate, calcium oxide are used to activate the fly ash in the ratio 1:8.

Utilization of Calcium Carbide Residue-Fly Ash Mixture as a …

This research utilizes the high calcium content in the fly ash to produce concrete with a commonly used method (just add the water without any alkali activator) and investigates how the water-to ...

A study on high strength concrete prepared with large volumes …

Low calcium fly ash (ASTM Class F) has been widely used as a replacement of cement in normal and high strength concrete [1], [2].In normal strength concrete, the replacement level can be more than 50% [3], [4], while in high strength concrete, the replacement level is usually limited to 15–25% [2].The main objectives of using fly ash in high …

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 ...

Low-Calcium, Fly-Ash-Based Geopolymer Concrete

26.12 Concluding Remarks This chapter presented information on heat-cured, fly-ash-based geopolymer concrete. Low-calcium fly ash (ASTM Class F) is used as the source material instead of the Portland cement to make concrete. Lowcalcium, fly-ash-based geopolymer concrete has excellent compressive strength and is suitable for structural applications.

Optimizing the Use of Fly Ash in Concrete

There is a low risk of ASR expansion occurring in the field when very high-volume fly ash concrete with 50% or more fly ash is used, however, testing is recommended when high-calcium fly ash is used. High-alkali fly ashes (> 5% Na2Oeq) are not recommended for use with potentially reactive aggregates.

Influence of rice husk ash on mechanical properties and fire …

In contrast, geopolymers made from high-calcium fly ash (HCF) are able to set and harden without heat curing. With moderate contents of calcium in the fly ash, higher geopolymer strength can be obtained when cured at room temperature (Provis, 2018). This helps expand the application of fly ash geopolymers beyond precast elements to the building ...

Compensating for Concrete Shrinkage with High-Calcium Fly Ash

The purpose of this work is to develop and study an expanding agent to concrete, including high-calcium fly ash and calcium nitrate as an expansion activator. The content of Ca(NO3)2 can be used to regulate the degree of expansion of the additive itself during hydration and, accordingly, to control shrinkage, thus obtaining shrinkage-free or ...

Assessment of equivalent substrate stiffness and mechanical …

High-calcium fly ash (HFA) and commercial silica fume (SF) were used as the precursors for producing the alkali-activated high-calcium fly ash concrete (AAHFAC). Sodium hydroxide (SH) and sodium silicate (SS) solutions were used as alkaline activator solutions with the constant SS/SH ratio of 1.0 and liquid-binder (L/B) ratio of 0.50.

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.

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

Fly ash can be utilised as a cement replacement, reducing cement usage, thus environmentally and economically beneficial. Fly ash makes concrete workable; increasing its …

Using Fly Ash in Concrete

A superplasticizer combined with fly ash can be used to make high-performance and high-strength concrete. Concrete containing fly ash generally performs better than plain …

Fire resistance of fly ash-based geopolymer concrete blended with

This paper presents a study on the high-temperature performance of fly ash-based geopolymer concrete cured at ambient temperature. Compression tests were carried out on geopolymer mortars at ...

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 widely ...

Properties of Cold-Bonded Lightweight Aggregate Based on High Calcium …

The object of research is a cold-bonded fly ash aggregate based on high-calcium fly ash from Berezovskaya GRES (Russia). The study presents a developed lightweight aggregate for concrete, consisting of high-calcium fly ash, microsilica and MgCl 2 and Ca(NO 3) 2 additives. The physical and mechanical properties of the filler were experimentally …

Chapter 3

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 …

Fly Ash Concrete and ICFs

More precisely, fly ash reacts with calcium hydroxide to form calcium silica hydrate, the substance that actually makes concrete hard. It allows the mix designer to substitute fly ash—available from the power …

Influence of recycled aggregate on fly ash geopolymer concrete …

We tested fly ash geopolymer concrete containing recycled concrete aggregate (RCA). • RCA can be used as a coarse aggregate in high calcium fly ash geopolymer concrete. • Relatively high compressive strengths of 30.6–38.4 MPa were obtained. • Durability of RCA geopolymer concretes were similar to normal limestone geopolymer concrete.

High calcium fly ash geopolymer mortar containing Portland cement …

The high calcium fly ash geopolymer mixture can be cured at room temperature as a result of the reaction of calcium in the system. However, the geopolymerization of high calcium fly ash without additives is still slow at ambient condition [10], [11], therefore, low strength is normally obtained.

Workability and strength of coarse high calcium fly ash geopolymer

In this paper, the basic properties viz., workability and strength of geopolymer mortar made from coarse lignite high calcium fly ash were investigated. The geopolymer was activated with sodium hydroxide (NaOH), sodium silicate and heat. The results revealed that the workable flow of geopolymer mortar was in the range of 110 ± 5%–135 ± 5% and was …

PERFORMANCE OF HIGH CALCIUM FLY ASH BASED GEOPOLYMER CONCRETE …

Download Citation | On Oct 1, 2020, Nur Ahmad Husin published PERFORMANCE OF HIGH CALCIUM FLY ASH BASED GEOPOLYMER CONCRETE IN CHLORIDE ENVIRONMENT | Find, read and cite all the research you need ...

Chapter 5

Flowable fills can use non-concrete grade fly ash, which may be obtained at a reduced cost. However, when sand is more economical, fly ash can be limited to 300 or fewer kilograms per cubic meter (500 or fewer pounds per cubic yard). ... * High calcium fly ash is used in lower amounts than low calcium fly ash. **Equal to 227 liters (60 gallons)

Novel Analytical Method for Mix Design and Performance

The geopolymer concrete mix proportions based on the ANN algorithm model and contour plots developed were experimentally validated. Thus, the proposed method can be used to determine mix designs for high calcium fly ash geopolymer concrete in the range 25–45 MPa at 28 days.

High Early Strength Fly Ash Concrete for …

1970s made Class C (high calcium) fly ash more readily available. Class C fly ash has a higher lime con tent than Class F fly ash and possesses some cementitious properties of its own. Therefore, this Class C fly ash can be used in higher proportions than the 15 to 20 percent range typically used for the Class F fly ash for structural

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

Fly ash for use in concrete: 2015: United Kingdom: BS EN 450-1: Fly ash for concrete. Definition, specifications and conformity criteria: 2012: BS EN 450-2: ... The use of law and high calcium FAs at up to 70 % volume resulted in a self-consolidating concrete with an acceptable CS (Şahmaran et al., 2009). According to this study the HVFA self ...

What Is Fly Ash and How Is It Used in Concrete?

However, the danger to humans, wildlife, and the environment presented by fly ash production can be mitigated by using fly ash to improve the composition of concrete. Since fly ash contains aluminous and siliceous components, it may form cement when mixed with water if the calcium content of the fly ash is high enough. Similarly, mixing fly ash ...

Chloride-induced corrosion of reinforcement in low-calcium fly ash

Low-calcium fly ash-based (Class F) GPC has been reported by some researchers to have lower chloride diffusion coefficients, chloride content and porosity compared to high-calcium (Class C) fly ash-based GPC and PCC [22], while others have found that the exact raw materials and mixture design can result in varying performance [23].Lloyd et al. [24] concluded …

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 replacing a portion of the HCF with LCF.

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