Technological aspects of usage of calcareous fly ash as a main constituent of cements

Gołaszewski, Jacek; Ponikiewski, Tomasz; Kostrzanowska–Siedlarz, Aleksandra; Miera, Patrycja

doi:10.3311/ppci.11164

Cited by 3 publications

(3 citation statements)

References 11 publications

(27 reference statements)

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“…Fly ash can be used as filler to contribute to self-compact backfill material instead of compacted soil or granular filling. Fly ash is also used to replace a part of cement in the concrete mix due to its cementitious features or it may mix with cement clinker and grind by milling [40]. ASTM C618 [41] defines fly ash as " the finely divided residue results from the combustion of ground and powdered coal and that is transported by flue gasses."…”

Section: Fly Ashmentioning

confidence: 99%

Using Cementitious Materials to Enhance Concrete Properties and Improve the Environment: A Review

Jabbar

2023

ejuow

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Cement production significantly contributes to carbon dioxide emissions, which increase global warming. Therefore, reducing cement consumption can support efforts to reduce that risk. On the other hand, the consumption of industrial wastes in concrete production contributes to improving the environment. Industrial waste can be used as supplementary cementitious materials (SCMs) to enhance concrete properties. This paper reviews the effects of SCMs, such as silica fume, fly ash, metakaolin, and ground granulated blast furnace slag (GGBFS), on the properties of fresh and hardened concrete. The findings show that SCMs enhance packing density and reduce permeability. The impact of SCMs on concrete properties appears after a period of curing depending on the availability of calcium hydroxide and activity index. Calcium hydroxide produced from cement hydration reacts with silicates of SCMs to produce additional calcium-silicate hydrates that enhance concrete strength and minimize the relatively large size of calcium hydroxide, which lowers porosity. Silica fume and metakaolin raise water demands and reduce workability, while GGBFS and fly ash improve workability. Silica fume, metakaolin, and (10) μm particle size of GGBFS increase early-age strength, (10-45) μm particle size of GGBFS enhances strength after 28 days, while fly ash raises the strength after 90 days. For low cement content, 10 % or less silica fume, (10-30) % fly ash, (10-20) % GGBFS or metakaolin are considered the perfect percentage to arrive at best strength. For high cement content, (25-30) % silica fume or 40 % fly ash is considered the optimum ratio to reach the highest strength.

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Section: Fly Ashmentioning

confidence: 99%

Using Cementitious Materials to Enhance Concrete Properties and Improve the Environment: A Review

Jabbar

2023

ejuow

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“…At the beginning, FA was mostly utilized as an additive to the admixtures of concrete for the benefits in workability of fresh concrete. Then, replacing various proportions of OPC with an appropriate amount of FA as a binder was found to be efficient to enhance mechanical properties of fly ash concrete (FAC) [1,2]. The actual FA amount used varies widely depending on the application, mechanical and chemical properties of FA, specification limits, as well as on the geographic location and climate.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Probabilistic Investigations of the Effect of Fly Ash Dosage on Concrete Compressive Strength and Stress-strain Relationship

Nguyen

Dang

2022

Period. Polytech. Civil Eng.

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The effect of fly ash (FA) dosage on concrete’s compressive strength and stress-strain relationship is investigated in two steps in this article. First, an experimental program was conducted on concrete mixtures designed with 0% (control batch of 30 MPa mean cylinder compressive strength), 10, 20, 30, and 40% of ordinary Portland cement (OPC) mass replaced by FA, which is taken from a new source in an Asia country. The test results showed that compared to other investigated dosages, concrete using 20%FA/OPC mass-replacement gained the most improvement in the 28-day compressive strength and tensile split strength, as well as the compressive strength development. Second, a probabilistic investigation was conducted using Dropout Neural Network, Bayesian Neural Network, and Gaussian Process models. These artificial intelligence-based models were compared to other models reviewed from the literature, showing relatively good results in terms of the statistical metric R2, which are 0.92, 0.9, and 0.88, respectively. The three models were tested and validated with a dataset of 1032 experimental results on FAC collected from the literature. When testing with the experimental results obtained in the first step, a good correlation between the predicted values and the experimental results was observed within the confidence interval of (5%, 95%), showing the reliability of the proposed models. Thus, the stress-strain relationship of fly ash concrete can also be investigated in a probabilistic manner. It is proved in this study that among the proposed models, Dropout Neural Network has the best balance between performance and time complexity.

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“…Therefore, it is imperative to solve the problem of coal ash properly [3][4][5]. At present, the utilization technology of fly ash as an admixture in the civil engineering and building materials industry is quite mature and has been popularized across China [6][7][8][9], whereas it is evidently not economically suitable to use the fly ash accumulated at substantial power plants as an admixture. Treating it as a kind of foundation material and as an artificial stratum can not only maximize the utilization of resources, but also solve the problem of accumulated fly ash that occupies land.…”

Section: Introductionmentioning

confidence: 99%

Model Test of Bearing Characteristics of Fly Ash Foundation under Cyclic Loading

et al. 2022

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Based on the vertical cyclic model test of the cement-fly ash mixing pile (CFMP) composite foundation, the effects of different dynamic load ratios on the long-term bearing characteristics of the composite foundation were studied. From the perspectives of foundation cumulative settlement, dynamic stiffness, pile axial force, and pile lateral friction, etc., the bearing mechanism of the CFMP fly ash composite foundation under cyclic load was investigated. By virtue of the assay herein, the authors discovered that the cumulative settlement under different load ratios exhibited the “threshold effect”, which could be divided into the attenuation type and destruction type. When the peak value of the cyclic load was close to the ultimate bearing capacity, the dynamic failure of the pile foundation occurred. The cyclic displacement ratio ranged from 1.05 to 1.23, satisfying the relation of quadratic equation. The cyclic load settlement could be predicted by the static load displacement. During cyclic loading, the proportion of the pile side sharing the upper load decreased persistently, and the fatigue degradation of side friction resistance occurred. The degradation could be alleviated by reducing the water content of fly ash and taking waterproof measures during construction.

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Technological aspects of usage of calcareous fly ash as a main constituent of cements

Cited by 3 publications

References 11 publications

Using Cementitious Materials to Enhance Concrete Properties and Improve the Environment: A Review

Using Cementitious Materials to Enhance Concrete Properties and Improve the Environment: A Review

Experimental and Probabilistic Investigations of the Effect of Fly Ash Dosage on Concrete Compressive Strength and Stress-strain Relationship

Model Test of Bearing Characteristics of Fly Ash Foundation under Cyclic Loading

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