A Study on the Evaluation of Field Application of High-Fluidity Concrete Containing High Volume Fly Ash

Choi, Yun-Wang; Park, Man‐Seok; Choi, Byung-Keol; Oh, Soo-Cheol

doi:10.1155/2015/507018

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…The mortar with high fly ash content (replacing up to 80% of fly ash) that meets the minimum compressive strength at an early age (R3 ≥ 13MPa, 3 days old) and (R28 ≥ 40MPa, 28 days old) will make an important contribution in sustainable development, reducing CO2 emissions by replacing Portland cement with fly ash, saving natural resources, and limiting environmental pollution on the impact of thermal power coal ash and construction industry using Portland cement. Moreover, with such required strength, it is suitable for the actual construction of civil works, or prefabricated components that need to be demoulded early and is equivalent to commercial products with the same compressive strength [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Early strength enhancement of high-volume fly ash mortar using accelerating admixtures

Vu Viet,

Le Van

2024

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High-volume fly ash mortar is considered a "green" material, a sustainable development solution for the construction industry, in which the fly ash replacement Portland cement content is over 50%. However, this material has the major disadvantage of slow strength development, especially at an early age, which limits its applicability. To overcome the above disadvantage, the individual or combined addition of lime Ca(OH)2, silica fume, and/or accelerating admixtures including sodium thiocyanate (NaSCN), diethanolamine (DEA), and glycerol (Gly), etc. have been interested recently. In this study, to enhance the early strength of mortars with fly ash content to replace 60÷80% of Portland cement, a three-component accelerating admixture of NaSCN, DEA, and Gly (2:1:0.5 by the mass) was used with different ratios of 0.21÷0.49 % by the total powder mass, combined with a reasonable amount of lime, silica fume supplement as presented in previous research. Experimental results showed that the optimal accelerating admixture content is 0.35% by weight of powder, combined with 6% silica fume and the additional amount of lime is 5%; 10%; and 15% corresponding to mortars using fly ash of 60%; 70% and 80%, respectively to improve early strength of mortars that are suitable for structural use (R3 ≥ 13MPa, 3 days old). In addition, the influence of the additives used on the initial setting time of high-volume fly ash mortars was also discussed.

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Section: Introductionmentioning

confidence: 99%

Early strength enhancement of high-volume fly ash mortar using accelerating admixtures

Vu Viet,

Le Van

2024

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“…The aim is to accelerate the hydration of both fly ash and cement and enhance the positive effects of fly ash on the refinement of pores and improvements in the microstructure and interfacial transition zones [29,31]. A study by Choi et al [32] indicated that by admixing superplasticizer and an air-entraining agent with a decreased water dosage and increased content of binders, a high-fluidity concrete with 50% fly ash content ensured early strength and reached the target strength at a curing age of 28 days. Yu et al [33] reported that by lowering the water-to-binder ratio and properly combining raw materials, concrete with 40-70% fly ash content had adequate strength and workability, and the mechanical properties could be improved by admixing a small amount of silica fume.…”

Section: Introductionmentioning

confidence: 99%

Case Study on the Performance of High-Flowing Steel-Fiber-Reinforced Mixed-Sand Concrete

Geng,

Zhang,

Wang

et al. 2023

Crystals

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To promote the efficient utilization of bulk solid wastes, including superfine river sand and fly ash, high-flowing steel-fiber-reinforced mixed-sand concrete (SFRMC) was developed in this study. Superfine river sand and coarse manufactured sand were mixed in a proportion of 4:6 to make the mixed sand. Fly ash, with a content of 30~75%, was blended with 0~12% silica fume on the premise of equivalent activity. The water dosage and sand ratio were adjusted with the volume fraction of steel fiber, which varied from 0.4 to 1.6%, to ensure the high flowability of fresh SFRMC. The mechanical properties, including cubic and axial compressive strengths, modulus of elasticity, splitting tensile strength, and flexural strength and toughness of the SFRMC, were analyzed, accounting for the influences of the contents of fly ash and steel fiber. The predictive formulas for the splitting tensile strength, modulus of elasticity, and flexural strength were proposed by introducing the influencing factors of steel fiber. The SFRMC showed an increased modulus of elasticity with increases in the steel fiber factor, and flexural toughness was enhanced with increased contents of both steel fiber and fly ash.

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“…Fly ash is a by-product of coal combustion in power stations, which presents as tiny grains with a certain pozzolanic activity. As one of the industrial solid wastes, fly ash has attracted much more attention on its comprehensive utilization to protect the environment (Wu and Lian, 1999;Choi et al, 2015;Amran et al, 2021). Based on its chemical composition, grain fineness, and pozzolanic activity, fly ash is classified into different types and is most widely used as a mineral admixture of cement and concrete (Wu and Lian, 1999;Li et al, 2013;GB/T1596-2017GB/T1596- , 2017.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve economic benefits from effective utilization of fly ash, studies have been done to improve the applicability of FAC with large content of fly ash. With the replacement of 50% cement by fly ash containing 6.49% calcium oxide, the high-fluidity FAC was made by admixing the superplasticizer and air-entraining agent; the early strength was ensured by decreasing the water dosage and increasing the content of binders, and then the strength at the curing age of 28 days reached the target (Choi et al, 2015). In case of the replacement of 20%-80% cement by fly ash, the flowability of fly ash cement composites is improved at paste and concrete level (Thiyagarajan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Preparation and Performance of Concrete With Large Content of Fly Ash

Geng

Zhou

et al. 2022

Front. Mater.

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Producing concrete with large content of fly ash attracts increasing attention in low carbon building materials. In this paper, the fly-ash concrete (FAC) with a content of fly ash no less than 50% total weight of binders was developed. The adaptability of fly ash used for concrete was firstly examined by testing the water requirement of normal consistency and the setting time for cement fly-ash paste, and the strengths of cement fly-ash mortar at the curing age of 7 and 28 days. The factors of water-to-binder ratio from 0.3 to 0.5, the content of fly-ash from 40% to 80%, and the excitation measures with additional Ca(OH)2 and steam curing at initial were considered. After that, the FAC was designed by adding an excessive content of fly ash to reduce the water-to-binder ratio from 0.50 to 0.26, and the content of fly-ash varied from 52% to 60%. Results show that the cement fly-ash paste presented a reduction of water requirement and an elongation of setting time with the increased content of fly ash. This provides a foundation of maintaining the workability of fresh FAC with a decreased water-to-binder ratio by adding the excessive content of fly ash. The cement fly-ash mortar had a lower early strength due to the slow reaction of fly-ash with Ca(OH)2, which could be improved by steam curing at the initial 24 h due to the excitation of fly-ash activity. At curing age of 28 days, the FAC had the expected axial compressive strength and modulus of elasticity, but the tensile strength was lower than predicted. At the curing age of 56 days, all the basic mechanical properties of FAC reached the prediction. The resistances of FAC to chloride ion penetration and carbonization were realized at a very high level as specified in codes.

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A Study on the Evaluation of Field Application of High-Fluidity Concrete Containing High Volume Fly Ash

Cited by 5 publications

References 7 publications

Early strength enhancement of high-volume fly ash mortar using accelerating admixtures

Early strength enhancement of high-volume fly ash mortar using accelerating admixtures

Case Study on the Performance of High-Flowing Steel-Fiber-Reinforced Mixed-Sand Concrete

Experimental Study on Preparation and Performance of Concrete With Large Content of Fly Ash

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