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Fly ash effects: III. The microaggregate effect of fly ash ...

2004-11-1  (1) The microaggregate effect of fly ash is strengthened with the increase of the fly ash content. From the micromechanics viewpoint, it is because of the increase of the amount of microaggregate. In the center particle hypothesis, increase in the fly ash content means increase in the amount of center particles and decrease of the space of center particles.

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Fly ash effects: III. The microaggregate effect of fly ash ...

It is pointed out that the microaggregate effect is an important effect of fly ash. It is strengthened with the increase of content of fly ash, but weakened with age. At early age, fly ash cannot fine the pore structure. At late age, fly ash may fine the pore structure. However, in general, the fining role is

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FLY ASH EFFECTS: III. THE MICROAGGREGATE EFFECT

THE MICROAGGREGATE EFFECT OF FLY ASH. Unreacted fly ash particle can still contribute to the properties of cement stone; this is known as the microaggregate effect of fly ash. In this article, the authors report on a systematic study of the microaggregate effects of fly ash; the study includes micromechanics, the hypothesis of center particle and pore size distribution.

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Fly ash effects: I. The morphological effect of fly ash ...

2003-12-1  In 1981, Danshen and Yinji and Danshen summarized the previous research results and put forward the hypothesis of “fly ash effects.” They considered that fly ash has three effects in concrete, i.e., morphological, activated and microaggregate effects. The three effects are relative each other.

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Fly ash effects: II. The active effect of fly ash ...

2004-11-1  In the base, the active effect of fly ash is studied. The studied results show that the active effect includes two aspects: (1) Fly ash has stronger pozzolanic activity and can react with Ca(OH) 2, and (2) it can promote the hydration of cement. When the content of fly ash is less, its pozzolanic activity can exert well, but its promoting role to the hydration of cement is weaker.

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Effect of Fly Ash with Different Particle Size ...

2020-9-15  On the other hand, fly ash plays a main role in the effect of microaggregates, and the hydration products form densely due to its good dispersion. Fly ash with different particle size distributions has a certain influence on the hydration reaction and the hydration reaction with S. Tsivilis distribution is improved.

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Effect of Fly Ash, Sinking Beads and Metakaolin on the ...

2018-1-20  Wang, A.Q.; Zhang, C.Z.; Sun, W.: Fly ash effects-III. The microaggregate effect of fly ash. Cem. Concr. Res. 34(11), 2061–2066 (2004) Article Google Scholar 2. Poon, C.S.; Wong, Y.L.; Lam, L.: The influence of different curing conditions onthe pore structure and related properties of fly-ash cement pastes and mortars. Constr.

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The analysis on strength and fly ash effect of roller ...

2000-1-1  The research results show that: (1) The strength at early ages of HFRCC is poor, while the fly ash effect is low or negative. (2) The strength of HFRCC increases rapidly following its curing age; meanwhile, the fly ash effect gradually improves and is more beneficial to raising flexural strength.

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Effect of fly ash on drying shrinkage of thermal ...

2017-12-14  Wang Aiqin, Zhang Chengzhi, Sun Wei. Fly Ash Effects: The Microaggregate Effect of Fly Ash[J]. Cement and concrete research, 2004, 34(11): 2 061–2 066. Article Google Scholar [10] Yu Zhuqing, Ye Guang. The Pore Structure of Cement Paste Blended with Fly Ash[J]. Construction and Building Materials, 2013, 45(8): 30–35

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A Novel Class F Fly Ash-Based Geopolymer and Its ...

2020-11-17  The positive effect fly ash content has on the fluidity of materials mainly results from (1) the microaggregate effect of fly ash: the standard for the fineness of cement is 325 mesh, and among all the fly ash, 47.03% of the fly ash particles (from

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Effect of Fly Ash, Sinking Beads and Metakaolin on the ...

2018-1-20  Wang, A.Q.; Zhang, C.Z.; Sun, W.: Fly ash effects-III. The microaggregate effect of fly ash. Cem. Concr. Res. 34(11), 2061–2066 (2004) Article Google Scholar 2. Poon, C.S.; Wong, Y.L.; Lam, L.: The influence of different curing conditions onthe pore structure and related properties of fly-ash cement pastes and mortars. Constr.

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Study of Durability of Concrete with Fly Ash as Fine ...

2019-4-16  Part of fly ash acts as a cementitious material and has a microaggregate effect, while the rest provides a volcanic ash effect, which is attributed to the presence of SiO 2 and Al 2 O 3.

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Effects of Fly Ash and Ground Granulated Blast

The fly ash and GGBFS can improve HSC’s resistance to chloride ion penetration significantly. However, the effects of fly ash and GGBFS on freezing-hawing resistance of HSC are not obvious. Besides, the fly ash will reduce freezing-hawing resistance of HSC only when the content of mineral powder is up to 36%.

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Mechanical properties of fly ash concrete composite ...

the usage rate, large quantities of fly ash are proposed to be incorporated in the structural and paving concrete mixes. The main effect of fly ash in concrete covers three aspects, often called morphologic effect, pozzolanic effect and microaggregate effect6. Morphologic effect in dicates there are many microbeads in fly ash working as

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Current Status and Prospect of Fly Ash Utilization in China

2014-6-25  morphological effect, active effect and microaggregate effect , fly ash can be used to produce concrete, as is another main utilization way of fly ash. About 48 Mt fly ash is consumed in

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Experimental Investigation and Quantitative

Therefore, the filling effect and the microaggregate effect are the major effects when the fly ash amount increases and the pozzolanic reaction is relatively weak. Figure 2 Effect of fly ash incorporation on the degree of the fly ash reaction.

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Microaggregate definition of microaggregate by

Therefore, the filling effect and the microaggregate effect are the major effects when the fly ash amount increases and the pozzolanic reaction is relatively weak. Experimental Investigation and Quantitative Calculation of the Degree of Hydration and Products in Fly Ash-Cement Mixtures.

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Application of Low-Field NMR to the Pore Structure of ...

2020-9-2  This trend shows that the appropriate amount of fly ash (no more than 30% in this paper) is helpful to reduce the porosity of concrete. However, when the FA content exceeded a critical value, too much fly ash weakened the microaggregate effect and slowed the hydration rate of the binder system so that the hydration products were reduced and there was not enough to fill the pores.

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A Novel Class F Fly Ash-Based Geopolymer and Its ...

2020-11-17  The positive effect fly ash content has on the fluidity of materials mainly results from (1) the microaggregate effect of fly ash: the standard for the fineness of cement is 325 mesh, and among all the fly ash, 47.03% of the fly ash particles (from

More

Mechanical properties of fly ash concrete composite ...

hence it benefits the fluidity. The microaggregate effect indicates that the microbeads in fly ash can disperse well in concrete and combine firmly with gel produced in cement hydration, and thus promote concrete density. The pozzolanic effect indicates that the unfixed Si02 and A1203 in fly ash can be activated by Ca(OH)2 product of

More

Effects of Fly Ash and Ground Granulated Blast

The fly ash and GGBFS can improve HSC’s resistance to chloride ion penetration significantly. However, the effects of fly ash and GGBFS on freezing-hawing resistance of HSC are not obvious. Besides, the fly ash will reduce freezing-hawing resistance of HSC only when the content of mineral powder is up to 36%.

More

Current Status and Prospect of Fly Ash Utilization in China

2014-6-25  morphological effect, active effect and microaggregate effect , fly ash can be used to produce concrete, as is another main utilization way of fly ash. About 48 Mt fly ash is consumed in

More

Experimental Investigation and Quantitative

Therefore, the filling effect and the microaggregate effect are the major effects when the fly ash amount increases and the pozzolanic reaction is relatively weak. Figure 2 Effect of fly ash incorporation on the degree of the fly ash reaction.

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Experimental Research on Foamed Mixture Lightweight

2019-7-30  paragraph is called ball effect or microaggregate effect of fly-ash.Withtheballeffect(e.g.,[29–33]),thestructure betweensphericalparticlesoffly-ashandcementparticles canbecloser,thusimprovingthewetdensityandunconfined compressivestrengthofFMLSFtoacertainextent.However, whenthefly

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Modelling chloride diffusion in concrete: Effect of fly ...

1999-4-1  Journal Article Copeland, K - Ash at Work. Because virtually all durability aspects of concrete are improved with a reduction in permeability, the use of fly ash improves concrete durability. Concrete water demand is typically reduced when using fly ash leading to a lower water cementitious ratio.

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Microaggregates definition of Microaggregates by

The contribution of ground fly ash to the strength before 3 days is mainly due to filling effect and microaggregate effect. The Influence of Ground Fly Ash on Cement Hydration and Mechanical Property of Mortar. Czegley et al., ...

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Internal Curing by SAP in Ultra-High Strength Concrete ...

2020-10-13  and fly ash demonstrated positive synergistic effects on the compressive strength. At the early age of hydration, the effectiveness of internal curing first increases and then decreases with the increase of fly ash and silica fume content. However, at the later age of hydration, the effectiveness of internal curing by SAP

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Effect of Fly Ash on Physical Properties of Ultisols from ...

2006-8-20  Application of fly ash at high rates (30 and 50%) to the Soil 1 (Typic Plinthudult) caused a significant change in microaggregate size distribution of soil, while nonsignificant differences were observed in the rates of 5, 10, and 20% of fly ash. But no apparent effect of fly ash application on soil microaggregate

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Mechanical properties of fly ash concrete composite ...

hence it benefits the fluidity. The microaggregate effect indicates that the microbeads in fly ash can disperse well in concrete and combine firmly with gel produced in cement hydration, and thus promote concrete density. The pozzolanic effect indicates that the unfixed Si02 and A1203 in fly ash can be activated by Ca(OH)2 product of

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Fly ash, silica fume, slag, and natural pozzolans in ...

2 天前  Fifty-eight concrete batches were made to study the effects of fly ash, silica fume, and aggregate type on mechanical properties and permeability of concretes. Class F fly ash was used at the levels of 10 to 50% as cement replacement on an equal weight basis. Silica fume was used at the levels of 5 to 15%.

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Mechanical Properties of High-Volume Fly Ash Strain ...

2019-8-16  Fly ash proved to be beneficial in the improvement of tensile and flexural ductility, but an extremely high volume of fly ash can provide only limited improvement. The HVFA-SHCC mix FA3.2 (with fly ash to binder ratio of about 76% by weight) designed in this

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Modelling chloride diffusion in concrete: Effect of fly ...

1999-4-1  Journal Article Copeland, K - Ash at Work. Because virtually all durability aspects of concrete are improved with a reduction in permeability, the use of fly ash improves concrete durability. Concrete water demand is typically reduced when using fly ash leading to a lower water cementitious ratio.

More

粉煤灰掺量对混凝土性能的影响-【维普期刊官网】- 中文期刊 ...

The experiment results show that adding of 15% fly ash can obviously improve the concrete strength, and has less effect on the carbonation of concrete depth under full maintenance, nevertheless, 30% fly ash has lesser improvement on strength, and has greater

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Microaggregates definition of Microaggregates by

The contribution of ground fly ash to the strength before 3 days is mainly due to filling effect and microaggregate effect. The Influence of Ground Fly Ash on Cement Hydration and Mechanical Property of Mortar. Czegley et al., ...

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Experimental Study on Coal Fly Ash-Based Gas

Gas-sealing coatings on coal mine roadway walls can effectively repress gas emission and are of importance to the safe operation of coal mining. In this study, the performance of coal fly ash (CFA)-based gas-sealing coatings was investigated, including the aspects of drying time, air tightness, impermeability, flame retardancy and antistatic properties.

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Internal Curing by SAP in Ultra-High Strength Concrete ...

2020-10-13  and fly ash demonstrated positive synergistic effects on the compressive strength. At the early age of hydration, the effectiveness of internal curing first increases and then decreases with the increase of fly ash and silica fume content. However, at the later age of hydration, the effectiveness of internal curing by SAP

More

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