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How much is bulk concrete sheared during pumping Feys Dimitri

"How Much is Bulk Concrete Sheared during Pumping?" by

Generally, SCC is said to be sheared during pumping, while for CVC, the shearing is only concentrated in the lubrication layer and the bulk concrete flows as a plug. This paper discusses the factors affecting the shear rate in the bulk concrete, and the additional flow rate caused by shearing the bulk concrete.

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Guide to Tremie Concrete for Deep Foundations

Dimitri Feys Missouri University of Science and Technology Figure 19 Simulations presenting flow of bulk concrete in a quarter of a diaphragm wall panel, shown Figure D.3 Schematic of a concrete vent due to loss in concrete mix workability during tremie placement (according to Figure 9.13, FHWA GEC10), where an interface layer can

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Parameters influencing pressure during pumping of self

When focus-QC J1K 2R1, Canada e-mail: [email protected] ing on the properties in fresh state, there is still a research gap between the characterisation of the fresh G. De Schutter concrete properties when it leaves the mixer or the Magnel Laboratory for Concrete Research, Department concrete truck and the flow of concrete in the of

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Cement & Concrete Composites

bulk concrete not undergoing any shearing, and the case where both the lubricating layer and the concrete undergoing some shearing, respectively. During the flow of concrete in a pipe, if the wall shear stress (s w) is smaller than the concrete yield stress (s 0), the bulk concrete is …

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Comparative Study of Different Measurement Methods for

During actual pumping, the concrete is sheared at high speed to form a lubrication layer. The general range of the maximum shear rate in the pipe flow of pumped concrete is from 107 1/s to 653.2 1/s for the pipe with a diameter of 127 mm and 73.6 1/s to 445 1/s for the pipe with a diameter of 152 mm [ 39 ].

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How much is bulk concrete sheared during pumping

The amount of shearing in the bulk concrete is affected by η LL /μ p and τ 0 /μ p. Mixtures with higher w/cm and with fly ash are less prone to shear-induced changes. In specific conditions, Conventional Vibrated Concrete can be sheared inside pipes.

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Changes in concrete properties during pumping and

Jun 01, 2018 · The hydraulic pressure gradient within concrete during pumping triggers the formation of the lubricating layer mainly due to flow-induced particle migration [12,13], but also due to the separation of water from the fines paste . The water separation is …

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Parameters influencing pressure during pumping of self

Jul 27, 2012 · The main difference between conventional vibrated concrete (CVC) and self-compacting concrete (SCC) is observed in the fresh state, as SCC has a significantly lower yield stress. On the other hand, the placement of SCC by means of pumping is done with the same equipment and following the same practical guidelines developed for CVC. It can be questioned whether the flow behaviour in pipes …

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How Much is Bulk Concrete Sheared during Pumping? - CORE

By Dimitri Feys. Cite . BibTex; Generally, SCC is said to be sheared during pumping, while for CVC, the shearing is only concentrated in the lubrication layer and the bulk concrete flows as a plug. This paper discusses the factors affecting the shear rate in the bulk concrete, and the additional flow rate caused by shearing the bulk concrete.

Learn More

How Much is Bulk Concrete Sheared during Pumping? - CORE

By Dimitri Feys. Cite . BibTex; Generally, SCC is said to be sheared during pumping, while for CVC, the shearing is only concentrated in the lubrication layer and the bulk concrete flows as a plug. This paper discusses the factors affecting the shear rate in the bulk concrete, and the additional flow rate caused by shearing the bulk concrete.

Learn More

How much is bulk concrete sheared during pumping?

Download Citation | How much is bulk concrete sheared during pumping? | Pumping is an efficient procedure to place concrete inside formworks. Practical guidelines have been developed to facilitate

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Experimental Insights into Concrete Flow-Regimes Subject

In this paper, the authors have focused on shear-induced particle migration (SIPM), its effect on concrete flow patterns, and lubricating layer formation during pumping. For this purpose, various volume-fractions ϕ of aggregates were selected. The particle migration was analyzed by applying two methods: sampling hardened concrete exposed to pumping and performing X-ray microcomputed

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Parameters influencing pressure during pumping of self

Jul 27, 2012 · As stated above, the shear rate in the sheared part of the concrete during pumping can reach up to 60 s −1 (or even higher if a higher discharge rate is applied), resulting in a discrepancy in the range of shear rate between the rheometer and the flow in the pipes. On the other hand, the maximum shear rate obtained in the Tattersall Mk-II rheometer is already a very high value for a concrete …

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Viscoelastic Properties of Fresh Cement Paste to Study the

Jun 28, 2016 · During concrete pumping, the migration and redistribution of particles occur in a pipe and the lubrication layer that forms between the bulk concrete and the pipe wall is the governing factor determining the flow behavior. In order to identify flow behavior of pumping, in this study, the viscoelastic properties related to the microstructural behavior of a flocculated suspension were examined

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How much is bulk concrete sheared during pumping

Oct 30, 2019 · , developed by Kaplan,, valid when a part of the bulk concrete is sheared: (1) Δ p = 2 R Q π R 2-R 4 μ p τ 0, L L + R 3 μ p τ 0 1 + R η LL 4 μ p η LL + τ 0, L L. When exposed to more extended pumping times, the fresh properties of the concrete change,, . Typically, viscosity is reduced, but the effect of pumping on yield stress is not fully clear yet.

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Materials | Free Full-Text | Estimation of Lubrication

It is well known from literature that pumping of concrete requires the formation of a lubrication layer [].Absence of this layer would lead to excessive pumping pressures and potentially blocking of the pumpline [].Many studies have been performed to predict pumping pressures of concrete, whether through the use of interface rheometers [1,3,4,5,6,7], the Sliper [8,9,10,11], or by measuring the

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Pumping of Fresh Concrete: Insights and Challenges

G. De Schutter, D. Feys, RILEM Technical Letters (2016) 1: 76 – 80 78 shear rates in the bulk concrete in pipe lines may be an order of magnitude larger than in a typical concrete rheometer [4-5]. As SCC has typically higher viscosity compared to CVC, higher pressures may be required to pump SCC, even if the

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Delft University of Technology A review on the pumping

Pumping is the most common technique used to transport fresh concrete in 15 construction sites. The large-scale use of concrete all over the world makes the pumping 16 increasingly important. A wide variety of additives and admixtures are incorporated into 17 modern concrete in order for sustainable development. The performance of modern concrete

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SelectedWorks - Dimitri Feys

Dr. Dimitri Feys is an Associate Professor, Materials Engineering, in the department of Civil, Architectural and Environmental Engineering at Missouri University of Science and Technology. How Much is Bulk Concrete Sheared during Pumping? Construction and Building Materials (2019) Dimitri Feys. Pumping is an efficient procedure to place

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Cement & Concrete Composites

bulk concrete not undergoing any shearing, and the case where both the lubricating layer and the concrete undergoing some shearing, respectively. During the flow of concrete in a pipe, if the wall shear stress (s w) is smaller than the concrete yield stress (s 0), the bulk concrete is …

Learn More