(PDF) Effect of lubrication layer on velocity profile of

The rheology of concrete is predominant for the required pressures in a pumping pipe. However, more detailed information is required on the formation and the properties of the lubrication layer

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Changes in rheology of self-consolidating concrete induced

Up to12%cash back · Feb 02, 2016 · As previously stated by the authors in, for self-consolidating concrete (SCC), shear rate values could reach 30–60 s −1 during pumping, in the bulk concrete. Assuming the lubrication layer has 10 times lower viscosity, the shear rate in this layer would be several 100 s −1. As shearing can significantly affect concrete rheology, SCC properties should be largely affected by pumping.

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Changes in rheology of self-consolidating concrete induced

dating concrete (SCC), shear rate values could reach 30–60 s-1 during pumping, in the bulk concrete. Assuming the lubrication layer has 10 times lower viscosity, the shear rate in this layer would be several 100 s-1. As shearing can significantly affect concrete rheology, SCC properties should be largely affected by pumping.

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Influence of pumping on the resistivity evolution of high

Oct 04, 2021 · The maximum shear rate applied to bulk concrete can be calculated as following : (3) γ ̇ p = τ b-τ 0 ' μ p = Δ p R b 2-τ 0 ' μ p where τ b is the shear stress at the boundary between the lubrication layer and bulk concrete (Pa), Δ p is the pressure loss per unit length (kPa/m), μ p is the plastic viscosity (Pa·s), and R b is the

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Effect of lubrication layer on velocity profile of

Jan 22, 2015 · The rheology of concrete is predominant for the required pressures in a pumping pipe. However, more detailed information is required on the formation and the properties of the lubrication layer near the pipe surface, in order to be able to accurately predict the pressure-discharge relation. By means of experimental research in combination with advanced numerical simulations, the lubrication

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Estimation of Lubrication Layer Thickness and Composition

During concrete pumping, a lubrication layer is formed near the pipe wall. Extensive research has been performed on measuring and modeling the properties of this layer and using these values to predict pumping pressures. However, there are numerous discussions in the literature about the composition …

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Estimation of Lubrication Layer Thickness and Composition

During concrete pumping, a lubrication layer is formed near the pipe wall. Extensive research has been performed on measuring and modeling the properties of this layer and using these values to predict pumping pressures. However, there are numerous discussions in the literature about the composition …

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Pumping of concrete mixtures: rheology, lubrication layer

Pumping of Concrete Mixtures: Rheology, Lubrication Layer Properties and Pumping Pressure Assessment Pumping is the most utilized placement technique to deliver fresh concrete from the concrete mixer to the formwork on construction site.

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Estimation of Lubrication Layer Thickness and Composition

it seems that the lubrication layer is composed of a mortar with a maximum particle size of around 1 to 2 mm. Keywords: lubrication layer; interface rheometer; rheology; concrete; mortar; viscosity; yield stress; pumping. 1. Introduction. It is well known from literature that pumping of concrete requires the formation of a lubrication layer [1].

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How do concrete rheology, tribology, flow rate and pipe

Feb 01, 2016 · The thickness of this layer is approximately 1.5–2 mm for a variety of concrete mixtures and pumping conditions, . With the recent developments in assessing the thickness of the lubrication layer, pumping pressure in straight pipes can be calculated if the rheological properties of the micro-mortar and concrete are known.

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Estimation of Lubrication Layer Thickness and Composition

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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Investigations on the Influence of Binders toward

Mar 03, 2020 · The lubrication layer of concrete plays a vital role in the pumping of concrete. In the present study, the influence of different types of binders ordinary portland cement (OPC), Portland pozzolana cement (PPC), portland slag cement (PSC), and solid volume fraction on the flow properties of the lubrication layer (cementitious pastes) corresponding to 3 grades (M30, M40, and M50) of concrete

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On rheology of mortar with recycled fine aggregate for 3D

1.Introduction. The intensive labor consumption as well as huge construction and demolition waste (CDW) are two main problems impeding the sustainable development of conventional construction industry,, .On the one hand, as a kind of digital manufacturing method, 3D concrete printing (3DCP) can linearly deposit cementitious mixtures layer upon layer to form structures without formworks, and

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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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Effect of lubrication layer on velocity profile of

The rheology of concrete is predominant for the required pressures in a pumping pipe. However, more detailed information is required on the formation and the properties of the lubrication layer near the pipe surface, in order to be able to accurately predict the pressure-discharge relation.

Learn More

Asphalt Mixing Plant For Sale - Asphalt Batch Plant

LB1000 asphalt mixing plant in Russia. Type: LB1000: Production Capacity(t/h) 80: Drying roller drive(KW) 5.5×4 So customer can choose types of hot mix asphalt according to their projects. Intermittent forced asphalt mixing plant. the batch type asphalt plant has different asphalt batch mix plant price.

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Pumping of Fresh Concrete: Insights and Challenges | RILEM

Nov 25, 2016 · Pumping of fresh concrete is of utmost importance for concrete practice. Required pumping pressures are typically estimated based on design charts. However, with the increased use of chemical admixtures and the development of more flowable concrete mixtures, the accuracy of traditional design charts is questioned. In recent years, significant progress has been obtained in …

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1. Introduction

Besides, the lubrication layer is of vital importance in concrete pumping process, which relates to the shear-induced migration of particle inside the pumping pipe [12]. Based on the theory of tribology, the rheological properties of the lubricating layer can be obtained, and the friction on the boundary can be calculated accurately [13]. In

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A Review on the Pumping Behavior of Modern Concrete

flow rate of concrete mixture is larger, the pumping pressure is higher. Then the shear stress near the inner wall of the pump pipe may exceed the yield stress of the fresh concrete. In addition to the formation of lubrication layer and block zone, the fresh concrete will also form a shear zone between block zone and lubrication layer.

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State of the Art on Prediction of Concrete Pumping

Large scale constructions needs to estimate a possibility for pumping concrete. In this paper, the state of the art on prediction of concrete pumping including analytical and experimental works is presented. The existing methods to measure the rheological properties of slip layer (or called lubricating layer…

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