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Pumping of concrete mixtures: rheology, lubrication layer ...

Pumping is the most utilized placement technique to deliver fresh concrete from the concrete mixer to the formwork on construction site. Compared to other available placement methods, such as bucket-and-crane or conveyor belts, pumping offers superior placement rates while reducing the required labor cost. Despite the fact that concrete pumping has been utilized on job sites around the world ...

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Lubrication layer properties during concrete pumping ...

Mar 01, 2013  This layer is often called in literature lubrication layer or sometimes slippage layer. Its existence was first suggested by Aleekseev and Weber .Morinaga noted that, from a theoretical point of view, considering the rheological parameters of the material, pumping of concrete would not be possible without the formation of this lubrication layer. . Sakuta et al. went further and showed that the ...

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Lubrication layer properties during concrete pumping ...

Abstract. In order to progress in the understanding of the physical phenomena involved in the pumping process of concrete, we study in this work the properties of the lubrication layer, which forms between the pipe and the bulk material. Using ultrasonic velocity profiler, we measure the

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Lubrication layer properties during concrete pumping ...

Pumping of concrete is impossible without the formation of a lubrication layer [22,23]. The shear-induced particle migration, the bleeding tendency of concrete, and the wall effect were considered ...

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Changes in fresh properties of flowable concrete induced ...

PUMPING AND COMPOSITION OF THE LUBRICATION LAYER by ALEXIS SALINAS A THESIS Presented to the Faculty of the Graduate School of the ... Rheology is better tool to evaluate the behavior of concrete. Pumping is a process that induces considerable shearing in the concrete that can impact its rheological properties. Therefore, the magnitude of these ...

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Formation of lubricating layer and flow type during ...

Jul 30, 2018  The existence of the lubricating layer (LL) and its high relevance to concrete pumping behaviour have been intensively discussed , , , , . The LL can be defined as a thin (a few millimetres) and dilute layer at the interface between concrete bulk and pipe wall subject to a pronounced velocity gradient induced by pumping pressure.

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(PDF) Effect of lubrication layer on velocity profile of ...

The stiffer the concrete, the more important the effect of the lubrication layer on the overall velocity profile. In most cases, the lubrication layer is the dominant effect for pumping of ...

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Pumping of Fresh Concrete: Insights and Challenges

4 Lubrication layer formation While pumping, the fresh concrete does not remain homogenous, due to the formation of a lubrication layer near the pipe wall (sometimes also misleadingly called ‘slip layer’ while no slip between concrete and surface occurs - [19-20] provide evidence of negligible flow velocity near the pipe wall).

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Avoidance of Blockages in Concrete Pumping Process ...

The concrete pump is often used in commercial construction and is particularly helpful where access is difficult (for example, in tunnels). ... Pumping of concrete mixtures: rheology, lubrication layer properties and pumping pressure assessment. J. Vosahlik; Materials Science ... Relationships between

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Rheological and pumping behaviour of 3D printable ...

Jan 01, 2021  Similar low yield stress values for the lubrication layer as compared to bulk concrete have been reported in the literature, though those studies were conducted on CVC and SCC [17,19,68]. The increase in yield stress of the lubrication layer is about 47% over the range of a/b investigated.

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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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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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A Review on the Pumping Behavior of Modern Concrete

facilitates the formation of lubrication layer (Secrieru et al. 2018a). The lubrication layer is a mortar-like layer formed on the pipe wall during the pumping process. The pumping resistance is in essence determined by the fric-tion between the pipe and the lubrication layer (Kwon

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Pumping of Fresh Concrete: Insights and Challenges

4 Lubrication layer formation While pumping, the fresh concrete does not remain homogenous, due to the formation of a lubrication layer near the pipe wall (sometimes also misleadingly called ‘slip layer’ while no slip between concrete and surface occurs - [19-20] provide evidence of negligible flow velocity near the pipe wall).

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Effect of lubrication layer on velocity profile of concrete ...

ORIGINAL ARTICLE Effect of lubrication layer on velocity profile of concrete in a pumping pipe H. D. Le • E. H. Kadri • S. Aggoun • J. Vierendeels • P. Troch • G. De Schutter Received ...

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Prediction of Concrete Pumping: Part I-Development of New ...

Request PDF Prediction of Concrete Pumping: Part I-Development of New Tribometer for Analysis of Lubricating Layer The character of the lubricating layer formed near the wall of a pipe during ...

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Estimation of Lubrication Layer Thickness and Composition ...

Apr 11, 2020  Abstract: 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

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KR20180096489A - Activation of Lubrication Layer and ...

According to an embodiment of the present invention, provided are an apparatus and a method for activation of a lubrication layer in a concrete conveying pipe, wherein the apparatus comprises: a liquid chemical injection unit injecting liquid chemicals for activating the flow of concrete into an inner circumferential surface of the concrete conveying pipe in a ring shape; a liquid chemical ...

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KR101853301B1 - Activation of Lubrication Layer and ...

The present invention relates to an apparatus for activating lubrication layer of a concrete pneumatic pipeline and a method for activating lubrication layer. The apparatus for activating lubrication layer of a concrete pneumatic pipeline and a method for activating lubrication layer according to the present invention comprises: a chemical liquid injecting unit for injecting chemical liquid ...

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Effects of Ultrafine Powders on the Properties of the ...

May 05, 2020  The thickness of the lubrication layer of each concrete mixture is determined using a microindentation test method. The results show that 1% nanoclay and nano-CaCO 3 replacement increases the rheological parameter values (e.g., yield stress, viscosity) of both bulk concrete and the lubrication layer. However, 1% marble powder replacement ...

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Rheological Control of 3D Printable Cement Paste and Mortars

Rheological Control of 3D Printable Cement Paste and Mortars Scott Z. Jones1, Dale P. Bentz1, Nicos S. Martys1, William L. George1, and Austin Thomas1,2 1National Institute of Standards and Technology 2University of New Haven [email protected]

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Research on Pump Primers for Friction Reduction of Wet-Mix ...

Mar 05, 2017  The solution with new concrete pump primers prepared (about 100 L solution with 2 kg primers for 100 m pipes according to the average 5 mm thickness of lubrication layer reported in [13, 14]) was firstly pumped through steel pipes to precreate the lubricating layer before pumping fresh concrete.

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Comparative Study of Different Measurement Methods for ...

The lubrication layer plays a governing role in predicting the pumpability of fresh concrete. To determine the effect of measurement methods on the characterization of the rheological properties of the lubrication layer, different measurement systems, including Sliper, tribometer, and

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A rheology-based quasi-static shape retention model for ...

Sep 10, 2020  A custom-built concrete extruder illustrated in Fig. 13 is used for this research, as the current SU 3D concrete printer is incapable of extruding large square cross-sectional filament layers. The concrete is fed into the rotating pump screw by pressure from the pneumatic controlled compressor plate.

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Prediction of Concrete Pumping Using Various Rheological ...

Jul 08, 2014  When concrete is being transported through a pipe, the lubrication layer is formed at the interface between concrete and the pipe wall and is the major factor facilitating concrete pumping. A possible mechanism that illustrates to the formation of the layer is the shear-induced particle migration and determining the rheological parameters is a paramount factor to simulate the concrete flow in ...

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Effect of lubrication layer on velocity profile of ...

The bulk of the concrete is sheared and/or shows a plug flow, depending on the yield stress of the concrete. The stiffer the concrete, the more important the effect of the lubrication layer on the overall velocity profile. In most cases, the lubrication layer is the dominant effect for pumping of concrete.

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"Changes in fresh properties of flowable concrete induced ...

The results showed that the fresh concrete properties are affected in diverse ways by pumping, with the results being dependent on the concrete fresh properties, and pumping parameters. Additionally, an attempt was performed to reverse engineer the composition of the so called 'lubrication layer' through the

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Prediction of Concrete Pumping: Part II—Analytical ...

Prediction of Concrete Pumping: Part II—Analytical Prediction and Experimental Verification. The primary objective of this study is to verify if the rheological properties of the lubricating layer obtained from the newly developed tribometer can give a good prediction of the real flow rates of pumped concrete.

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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. By means of experimental research in combination with advanced numerical simulations, the lubrication ...

Get Price

Effects of Ultrafine Powders on the Properties of the ...

May 05, 2020  The thickness of the lubrication layer of each concrete mixture is determined using a microindentation test method. The results show that 1% nanoclay and nano-CaCO 3 replacement increases the rheological parameter values (e.g., yield stress, viscosity) of both bulk concrete and the lubrication layer. However, 1% marble powder replacement ...

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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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A review on the pumping behavior of modern concrete — TU ...

This paper presents a comprehensive overview on the state of the art of concrete pumping. The models and methods used for characterizing the concrete pumpability and lubrication layer are described. The factors influencing the pumping behavior are discussed. A couple of ultra-high pumping engineering of concrete conducted in China are introduced.

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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

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Estimation of the Pumping Pressure from Concrete ...

A new method is proposed to estimate pumping pressure based on concrete composition without experimental measurements. Previous studies show that the pumping pressure depends on the interface friction between concrete and the wall of the pumping pipes. This friction is determined by the thickness and the rheology of the boundary layer formed at the interface.

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Lubricating suspension for pumping concrete - Sika AG ...

Nov 25, 1992  What is claimed is: 1. In a method comprising pumping concrete or mortar through a concrete or mortar pumping system, introducing a lubricating phase into the pumping system prior to the introduction of, or downstream relative to the front edge flow boundry, of said concrete or mortar, wherein said lubricating phase comprises an aqueous suspension of (i) at least one water-dispersed polymer ...

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DigitalConcrete 2018 Pumping

In this lecture, the basics for pumping concrete are introduced. The flow mechanisms in a pumping pipe are linked with the rheological properties of the concrete. The major role of the lubrication layer is explained, besides the shear and plug flow in the bulk of the pipe. Required pumping pressures are typically estimated based on design charts.

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Prediction of Pumping Pressure by Means of New Tribometer ...

Abstract. Predicting pressure during pumping has received special attention in recent years. For conventional vibrated concrete (CVC), Kaplan et al. developed a tribometer to characterize the properties of the lubrication layer that is formed when concrete flows in a pipeline, to predict pressure.

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3D Concrete Printing: A Systematic Review of Rheology, Mix ...

This paper provides a state-of-the-art report on the up-to-date research on the emerging 3D concrete printing technology from the concrete materials perspective. It reviews the recent research focused on understanding and characterizing the rheological ...

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