Viscosity influence on rising behavior of model air bubbles in fresh mortar

Han, Di; Lee, Gun-Cheol; Yoon, Seung-joe; Kim, Kyoung-Min

doi:10.1016/j.conbuildmat.2014.11.016

Cited by 11 publications

(5 citation statements)

References 10 publications

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“…This motion is facilitated by a combination of factors, including the mixing action, gravity, frictional forces, and the viscosity of cement paste. The greater the frictional force on the tagged particles, the more challenging their motion becomes [ 25 ]. This is similar to the research conclusions drawn by previous scholars on the movement of aggregates and fibers, indicating that the primary mechanism of solid phase movement in cement-based slurries is similar [ 18 , 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Effect of Vibration Procedure on Particle Distribution of Cement Paste

et al. 2023

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Vibration procedures significantly affect the performances of cement-based materials. However, studies on the distribution of certain particles within cement-based materials are limited due to the complexity and difficulty of identifying each specific particle. This paper presents a new method for simulating and quantifying the movements of particles within cement paste through the use of “tagged materials”. By separating the tagged particles from the cement paste after vibration, the distribution of the particles in the cement paste can be calculated statistically. The effect of the vibration time and frequency, fresh behavior, and powder characteristics of cement paste on particle motions are investigated. The results demonstrate that when the vibration exceeds 1800 s, it induces a significant uneven dispersion of microparticles. This effect is more pronounced at low viscosities (<1 Pa·s) of cement paste or high vibration frequencies (>200 Hz). Larger and denser particles exhibit greater dispersion. This method provides a valuable tool for investigating the theory of particle motion in cement paste, which is crucial for understanding the influence of vibration on the properties of cement-based materials.

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Section: Resultsmentioning

confidence: 99%

Effect of Vibration Procedure on Particle Distribution of Cement Paste

et al. 2023

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“…the minimum shear stress required to initiate flow) [25,26], and is generally considered to be sufficient to control the workability of conventional vibrated concrete. Plastic viscosity has been considered to be most relevant for controlling the resistance to segregation and bleeding of highly-flowable concrete [27][28][29], although it has been found that it may also interfere with the migration of air bubbles in mortars [30].…”

Section: Performance Properties Versus Slumpmentioning

confidence: 99%

On the role of compaction in disputes over the quality of the supplied concrete

et al. 2023

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This paper evaluates the effect of poor compaction on the compressive strength, sorptivity, gas permeability and accelerated carbonation resistance of bulk concrete in structures, framed in the scenario of disputes over the quality of the supplied concrete. For that purpose, several real-scale elements (beams, columns and slabs) were cast with concrete incorporating Portland-limestone cement and fly ash addition, covering a wide range of slumps (35–123 mm) and compressive strengths (25–65 MPa). The elements were then subjected to different compaction conditions (standard vibration and no vibration), and later cored for concrete testing. A new compaction indicator that overcomes the main practical limitations associated with the determination of the excess voidage of concrete is proposed, as well as new factors for correcting the effects of on-site compaction in the estimation of the potential carbonation resistance and the compressive strength of concrete. It is also shown that vibration no longer improves the quality of bulk concrete in structures for slumps above ~ 140 mm, which suggests that, in cases of dispute where greater slumps are specified, no correction for compaction should be needed in the estimation of the potential properties of concrete.

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“…Han et al [39] investigated the migration of air bubbles migrate into a vibrated cement mortar (Figure 41). The air bubble movement was modeled using expandable polystyrene (EPS) beads with EPS dispersion.…”

Section: Review Of Air Bubble Injection In Different Mediasmentioning

confidence: 99%

“…Figure 41. A schematic diagram of vibrated cement mortarwith cylinder mold and formulating samples[39] …”

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confidence: 99%

An Examination of Air-Bubble Injection Mechanisms for Optimising Heat Transfer in Industrial Applications

Rashid,

Basem,

Al-Obaidi

et al. 2023

IJHT

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The optimisation of heat transfer, which is the transition of thermal energy from regions of high temperature to those of lower temperature, is a cornerstone in the field of thermal sciences and engineering. It is of vital importance to maximise energy efficiency, ensure system performance, and uphold operational reliability across numerous industrial applications. In this context, recent investigations have explored the modification of heat transfer rates through the turbulence induced by air-bubble injections. The technique has found application in heat exchangers, solar stills, and solar collectors, where it can be employed to either augment or attenuate heat transmission. The majority of the research has been dedicated to enhancing thermal efficiency, with both theoretical models and experimental data underpinning our current understanding. This review provides a critical analysis of over 45 studies from the literature, which have examined the implications of air bubble injection across various realms of industry, including heat exchangers, water desalination systems, solar collectors, and diverse media. Our analysis underscores the profound impact of heat transfer rates on process productivity, efficiency, and costeffectiveness across a gamut of applications. A range of industrial processes, such as cooling, heating, evaporation, and condensation, all rely heavily on efficient heat exchange. Enhancements in heat transfer rates hold the potential to curtail energy losses, reduce fuel consumption, and subsequently lower operational costs in industrial applications like solar thermal systems. Moreover, efficient heat transfer is pivotal in minimising temperature variations, thereby contributing to consistent outcomes.

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Viscosity influence on rising behavior of model air bubbles in fresh mortar

Cited by 11 publications

References 10 publications

Effect of Vibration Procedure on Particle Distribution of Cement Paste

Effect of Vibration Procedure on Particle Distribution of Cement Paste

On the role of compaction in disputes over the quality of the supplied concrete

An Examination of Air-Bubble Injection Mechanisms for Optimising Heat Transfer in Industrial Applications

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