Effect of initial moisture of wet fly ash on the workability and compressive strength of mortar and concrete

Nguyen, Thuy Bich Thi; Saengsoy, Warangkana; Tangtermsirikul, Somnuk

doi:10.1016/j.conbuildmat.2018.06.192

Cited by 28 publications

(12 citation statements)

References 17 publications

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“…Therefore, it was noted that FA-based blends need more water to maintain the required flow value. A similar trend was reported by Nguyen et al [45].…”

Section: Workability Of Fresh Mortarsupporting

confidence: 91%

Sustainable Masonry Mortars with Fly Ash, Blast Furnace Granulated Slag and Wheat Straw Ash

et al. 2021

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Due to greenhouse gas emissions, the production of cement clinker is considered unsustainable and many attempts are being made to replace cement with alternative materials sourced from agriculture, industry and other urban practices, such as construction and demolition works. The aim of this paper is to analyze the effects of cement substitution by locally available waste materials in Serbia, such as fly ash (FA), blast furnace granulated slag (BFGS) and wheat straw ash (WSA), up to the 50% replacement volume rate in cement–lime mortars. As the effective application of supplementary cementitious materials (SCMs) in cement-based materials requires a comprehensive insight into their properties, a characterization of materials involving all relevant physical, chemical and mechanical tests is conducted. Ten different mortar mixed with ingredients of a volume ratio 1:2:4 (cementitious powder/lime/sand) were designed and their consistency, bulk density, capillary water absorption, flexural strength, compressive strength and thermal analysis (TGA/DTA) results were examined to determine the influence of the abovementioned SCMs on mortar properties. Research findings highlight the possibility of replacing cement with slag (50%), fly ash (30%) or wheat straw ash (30%) while maintaining its performance and improving the economic and environmental impacts of masonry mortar production.

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“…Therefore, it was noted that FA-based blends need more water to maintain the required flow value. A similar trend was reported by Nguyen et al [45].…”

Section: Workability Of Fresh Mortarsupporting

confidence: 91%

Sustainable Masonry Mortars with Fly Ash, Blast Furnace Granulated Slag and Wheat Straw Ash

et al. 2021

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“…Third, the mixing process of mortars containing wet bottom ashes is equivalent to a double mixing process where the first water of the double mixing equals the amount of surface water of the fine aggregates together with a part of the retained water in the bottom ashes [26]. According to the previous reasons, this water is higher in expansive mortars with the use of bottom ashes.…”

Section: Workabilitymentioning

confidence: 99%

Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Nguyen¹,

Saengsoy²,

Tangtermsirikul³

2019

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This study investigates the influence of bottom ashes with different water retainabilities as an internal curing material on the performances of mixtures containing an expansive additive and fly ash. Two series of experiments were conducted: mortar containing expansive agent (expansive mortar) with a controlled w/b ratio and concrete containing expansive agent (expansive concrete) with a controlled initial slump. Test results indicate that workability of expansive mortar is improved due to retained water of bottom ash. Compressive strength of expansive mortar with bottom ash decreases. Total shrinkage of the expansive mortars, with a constant w/b, increases with the use of bottom ashes that have high water retainability in the condition of 7 days of water curing and then air curing. However, by using bottom ashes, compressive strength increases when the slump of the expansive concrete is controlled due to decrease of w/b ratio. The internal curing ability of bottom ashes leads to enhanced expansion of expansive mortars with sealed curing and expansive concretes with moist curing, reducing total shrinkage of expansive mortars with air curing. It was found by DTG analysis that expansive concretes with higher expansion containing bottom ash with higher water retainability had a higher amount of ettringite.

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“…Fly ash is widely used as a supplementary cementitious material (SCM) in concrete due to its pozzolanic reaction. Higher workability of concrete mixture with a higher volume of fly ash was reported in many previous studies [8][9][10][11][12]. The compressive strength of fly ash concrete increases in the long term when compared to that of conventional concrete due to the pozzolanic reaction generating denser pore structure in concrete [13][14][15].…”

Section: Introductionmentioning

confidence: 70%

Influence of Initial Temperature of Fresh Concrete on Compressive Strength of Concrete

Nguyen¹

2023

GEOMATE

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This paper aims to evaluate the influence of initial temperature of fresh concrete on compressive strength and degree of reactions of binder in concrete with and without fly ash. The aggregates are cooled before being used to mix the concrete to achieve the temperatures of fresh concrete of 18°C, 25°C, and 30°C. After 24 hours in the mould, the concrete specimens are continually cured in water at 28 ± 2°C. Test results indicate that the compressive strength of the concrete at an early age decreases when the initial temperature of the fresh concrete decreases. However, the compressive strength of concrete at 91 days increases in the case of low initial temperature of fresh concrete. The effect of initial cooling is more obvious in concrete with higher fly ash content. The bound water, degree of reactions, and C-S-H content, the paste samples were analyzed by TGA. The lower initial temperature of fresh concrete leads to a lower rate of the degree of reaction and produces less amount of C-S-H at an early age. The degree of reaction of the binder at an early age affects early strength and long-term pozzolanic reaction that causes long-term strength. A lower initial temperature of fresh concrete reduces the early hydration of cement and delays the start of the pozzolanic reaction, resulting in an enhancement of the compressive strength at later ages. The degree of reaction and C-S-H content correlated well with the compressive strength of the concrete at early and long-term ages.

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Effect of initial moisture of wet fly ash on the workability and compressive strength of mortar and concrete

Cited by 28 publications

References 17 publications

Sustainable Masonry Mortars with Fly Ash, Blast Furnace Granulated Slag and Wheat Straw Ash

Sustainable Masonry Mortars with Fly Ash, Blast Furnace Granulated Slag and Wheat Straw Ash

Influence of Bottom Ashes with Different Water Retainabilities on Properties of Expansive Mortars and Expansive Concretes

Influence of Initial Temperature of Fresh Concrete on Compressive Strength of Concrete

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