Experimental Study on the Impact of Admixture for Concrete Heat of Hydration and Early-Age Contractile Properties

Sun, Jian; Wang, Bo Jun; Zhao, Weiqiang

doi:10.4028/www.scientific.net/amm.253-255.385

Cited by 7 publications

(4 citation statements)

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“…Some concrete products are typically made with a specific class of cement. For instance, concrete in very large foundations will use ggbfs to reduce the heat of hydration and prevent cracking (Sun et al, 2013;Tang et al, 2015). This kind of information is not available for most applications.…”

Section: Mapping Materials Flowmentioning

confidence: 99%

How much cement can we do without? Lessons from cement material flows in the UK

Shanks

Dunant

Drewniok

et al. 2019

Resources, Conservation and Recycling

128

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Cement manufacture is responsible for 5-7 % of world CO 2 emissions. Cement is primarily used in concrete, the most used material on the planet and a critical part of any analysis of emissions reduction strategy. To estimate the potential for reducing demand, this work analyses material flow in the cement industry, using the uk in 2014 as a case study. Combining published data, analytic assumptions, and interviews we estimated the material flow of cement from the production to a breakdown of its use in applications. Having broken down the demand for cement into 25 applications, multiple material efficiency techniques were considered: substituting cement for calcined clay and limestone, reducing the cement content of concrete, post-tensioning floor slabs, using more precast building elements, reducing construction waste, and reducing the overdesign in construction. We produce a final estimate of the total reduction in emissions achievable from material efficiency: 51.3 %. Due to overlap and interactions between the methods, the attribution of the carbon abatement depends on the sequence of application. In this analysis, we have applied the reduction of overdesign last, because it is independent of the others, and would require a cultural change. We show then that cement demand from floors, repairs and maintenance, concrete beams, and applications within the transport sector should be targeted. The substitution of cement with calcined clay and limestone has the biggest potential to reduce cement demand (27 %) and carbon emissions in the uk. Reducing the amount of cement in concrete has the next highest * Corresponding author Preprint submitted to Elsevier today potential (10 %), followed by post-tensioning floor slabs (3 %).

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Section: Mapping Materials Flowmentioning

confidence: 99%

How much cement can we do without? Lessons from cement material flows in the UK

Shanks

Dunant

Drewniok

et al. 2019

Resources, Conservation and Recycling

128

View full text Add to dashboard Cite

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“…is is well explained by equation (16). In the stage of increasing concrete temperature, when the concrete structure is thinner, (Q rise /Q total ) is smaller and (Q lost /Q total ) is larger, so the T max decreases more; at the same time, boundary conditions affect the value of (Q lost /Q total ), so different boundary conditions have different effects.…”

Section: Discussionmentioning

confidence: 97%

“…As an effective means to improve the thermal and mechanical properties of concrete, concrete admixtures have been widely used in engineering [13][14][15]. Commonly used concrete admixtures include water-reducing agents, retarders, air-entraining agents, etc., among which water-reducing agents can reduce the use of water and reduce the heat released by the hydration reaction [16].…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydration Heat Inhibitor on Thermal Stress of Hydraulic Structures with Different Thicknesses

Shen

et al. 2020

Advances in Civil Engineering

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Concrete hydration heat inhibitor can inhibit the early hydration reaction of concrete and reduce the initial heat release of concrete. However, there is no in-depth research on the effect of hydration heat inhibitor on hydraulic structures with different thicknesses and constraints. In this paper, numerical simulation is used to study the change of temperature and stress field after adding hydration heat inhibitor by establishing the finite element models of tunnel lining, sluice, and gravity dam. The results show that the effect of the hydration heat inhibitors on reducing the temperature peak is inversely proportional to the thickness of the structure. A formula is put forward to evaluate their relation in this paper. When the thickness of the structure is about 6 m, there is no peak cutting effect. For the stress field, hydration heat inhibitor can greatly reduce the thermal stress of the thin-walled structure and make the structure meet the temperature control requirements; for the medium wall thickness structure, it can reduce the internal tensile stress about 50% and the surface tensile stress about 20%, and other temperature control measures are still needed to ensure that the surface tensile stress of the structure meets the requirements; for hydraulic structures with large volume and thickness, the application effect of the inhibitor has limitations, which can reduce the internal tensile stress about 30%, but the tensile stress in the surface area will increase about 7% due to the increase of the internal and external temperature difference; therefore, other temperature control measures such as arranging cooling water pipe, strengthening surface insulation, and so on are needed to ensure that temperature cracks do not occur. This paper provides references and suggestions for the research and engineering application of hydration heat inhibitor.

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“…The results showed that fly ash and granulated blast furnace slag significantly increased the workability and compression strength of self-compacting concrete mixtures, and the best resistance to sodium and magnesium sulphate attacks was obtained from a combination of 40% granulated blast furnace slag with 60% cement. In addition, the use of mineral admixtures to replace cement in concrete can effectively save engineering costs, reduce the early hydration heat of concrete, and the thermal expansion coefficient of cement slurry, resulting in the reduction of concrete shrinkage and crack formation [ 16 ]. Zhang et al [ 17 ] evaluated the effect of mineral admixtures on the hydration heat of the binder paste in high-performance concrete and found that mineral admixtures greatly reduced the hydration heat and the exothermic rate and prolonged the arrival time of the highest temperature, particularly when two or three types of mineral admixtures were added at the same time.…”

Section: Introductionmentioning

confidence: 99%

Early-Age Mechanical Characteristics and Microstructure of Concrete Containing Mineral Admixtures under the Environment of Low Humidity and Large Temperature Variation

Guo

Zhang

et al. 2021

Materials

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The application of concrete containing mineral admixtures was attempted in Northwest China in this study, where the environment has the characteristics of low humidity and large temperature variation. The harsh environment was simulated by using an environmental chamber in the laboratory and four types of concrete were prepared, including ordinary concrete and three kinds of mineral admixture concretes with different contents of fly ash and blast-furnace slag. These concretes were cured in the environmental chamber according to the real curing conditions during construction. The compression strength, fracture properties, SEM images, air-void characteristics, and X-ray diffraction features were researched at the early ages of curing before 28 d. The results showed that the addition of fly ash and slag can improve the compression strength and fracture properties of concrete in the environment of low humidity and large temperature variation. The optimal mixing of mineral admixture was 10% fly ash and 20% slag by replacing the cement in concrete, which can improve the compression strength, initial fracture toughness, unstable fracture toughness, and fracture energy by 23.9%, 25.2%, 45.3%, and 22.6%, respectively, compared to ordinary concrete. Through the analysis of the microstructure of concrete, the addition of fly ash and slag can weaken the negative effects of the harsh environment of low humidity and large temperature variation on concrete microstructure and cement hydration.

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Experimental Study on the Impact of Admixture for Concrete Heat of Hydration and Early-Age Contractile Properties

Cited by 7 publications

References 0 publications

How much cement can we do without? Lessons from cement material flows in the UK

How much cement can we do without? Lessons from cement material flows in the UK

Effect of Hydration Heat Inhibitor on Thermal Stress of Hydraulic Structures with Different Thicknesses

Early-Age Mechanical Characteristics and Microstructure of Concrete Containing Mineral Admixtures under the Environment of Low Humidity and Large Temperature Variation

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