Pumping of concrete mixtures rheology lubrication layer

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Pumping of Concrete Mixtures: Rheology, Lubrication Layer ...

A four-phase research study was carried out to: (1) improve the existing methodology of rheological characterization of the lubrication layer formed during pumping, (2) evaluate the effect of concrete mixture constituents and proportioning on rheological properties of concrete and the lubrication layer, (3) asses the effect of pumping and ...

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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. Compared to other available placement methods, such as bucket-and-crane or conveyor belts, pumping offers superior placement rates while reducing

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

Pumping of concrete mixtures: rheology, lubrication layer properties and pumping pressure assessment . By Jan Vosahlik. Abstract ...

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Lubrication layer properties during concrete pumping ...

01/03/2013  Pumping of concrete can therefore be considered in most cases as the shearing of an annular layer of unknown thickness and made of a material with unknown rheological properties. Download : Download full-size image Fig. 1. Schematic pattern of concrete flow in the pipe.

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Pumping of Fresh Concrete: Insights and Challenges

Keywords: Pumping; Concrete;Rheology;Lubrication layer ; Pressure 1 Introduction Although the Romans mastered concrete construction in an amazing way (considering the scientific and technological knowledge in that era), we now have about a century of experience of working with modern concrete construction. However, new developments in powder and admixture technology have given a boost to

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Read Download Pumping Of Concrete Mixtures PDF – PDF

A four-phase research study was carried out to: (1) improve the existing methodology of rheological characterization of the lubrication layer formed during pumping, (2) evaluate the effect of concrete mixture constituents and proportioning on rheological properties of concrete and the lubrication layer, (3) asses the effect of pumping and pumping pressure on concrete fresh properties and the ...

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Interactions between rheological properties and pumping of ...

The effects of these ultrafine powders on rheology of the concrete and the properties of the lubrication layer, near the steel pipe–concrete interface, are studied by a portable rheometer and ...

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Read Download Pumping Of Concrete Mixtures PDF – PDF

A four-phase research study was carried out to: (1) improve the existing methodology of rheological characterization of the lubrication layer formed during pumping, (2) evaluate the effect of concrete mixture constituents and proportioning on rheological properties of concrete and the lubrication layer, (3) asses the effect of pumping and pumping pressure on concrete fresh properties and the ...

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Interactions between rheological properties and pumping of ...

The effects of these ultrafine powders on rheology of the concrete and the properties of the lubrication layer, near the steel pipe–concrete interface, are studied by a portable rheometer and ...

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Study on concrete pumpability combining different ...

30/07/2017  For this purpose, the material forming the lubrication layer (LL) is sampled from the various concrete mixtures. The results confirm that in addition to the rheological properties of the bulk of fresh concrete, the properties of the lubrication layer and the roughness of the pipe-wall significantly affect concrete flow in pipes. Based on the composition of the concrete and 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 and thickness of this layer: can it be considered mortar, a micromortar, or is it cement paste ...

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

05/05/2020  The effects of these ultrafine powders on rheology of the concrete and the properties of the lubrication layer, near the steel pipe–concrete interface, are studied by a portable rheometer and tribometer. The thickness of the lubrication layer of each concrete mixture is determined using a microindentation test method. The results show that 1% nanoclay and

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Estimation of Lubrication Layer Thickness and Composition ...

11/04/2020  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]. Absence of this layer would lead to excessive pumping pressures and potentially blocking of the pumpline [2 ...

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Effect of Electromagnetic Pulsation on the Rheological ...

25/08/2019  Moreover, the lubrication layer formed at the interface between pipe and material during pumping, being the main influencing factor on pumping of cementitious materials, will be examined. The effect of the alternating electromagnetic field on the lubrication layer was experimentally simulated with a sliding pipe rheometer. Results for the bulk material and the lubrication layer will be ...

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Viscoelastic Properties of Fresh Cement Paste to Study the ...

Keywords: concrete pumping, lubrication layer, dynamic oscillatory measurement, viscoelastic. 1. Introduction Concrete pumping involves the flow of a complex fluid under high pressure in a pipe, and thus predicting flow behaviors of concrete pumping is challenging research area. For the characterization and prediction of the flow of con-crete pumping, the fundamental understanding of ...

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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. This kind of flow state is known as friction flow and ...

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Pumping of Fresh Concrete: Insights and Challenges RILEM ...

25/11/2016  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 understanding the flow of the material in the pumping pipe, including the behavior of the lubrication layer near the pipe surface. In comparison with traditional

Get price

Estimation of Lubrication Layer Thickness and Composition ...

11/04/2020  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]. Absence of this layer would lead to excessive pumping pressures and potentially blocking of the pumpline [2 ...

Get price

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 and thickness of this layer: can it be considered mortar, a micromortar, or is it cement paste ...

Get price

DigitalConcrete 2018 Pumping

Pumping is a very efficient way of transporting concrete to its final position. Although extensive practical experience is available, pumping modern concrete mixtures can be challenging. 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 ...

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Pumping of Fresh Concrete: Insights and Challenges RILEM ...

25/11/2016  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 understanding the flow of the material in the pumping pipe, including the behavior of the lubrication layer near the pipe surface. In comparison with traditional

Get price

Viscoelastic Properties of Fresh Cement Paste to Study the ...

Keywords: concrete pumping, lubrication layer, dynamic oscillatory measurement, viscoelastic. 1. Introduction Concrete pumping involves the flow of a complex fluid under high pressure in a pipe, and thus predicting flow behaviors of concrete pumping is challenging research area. For the characterization and prediction of the flow of con-crete pumping, the fundamental understanding of ...

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A new method to estimate rheological properties of ...

the piping such as lubrication layer formation and . velocity distribution in the pipe and to analyze the material to be pumped. When concrete is . pumped, a lubricating layer forms between the pipe wall and the inner concrete. According to the . preceding stud. ies on concrete pumping (Alekseev 1952, Browne and Bamforth 1977, Choi . et al. Corresponding author, Professor, E-mail: [email protected] ...

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

05/05/2020  The effects of these ultrafine powders on rheology of the concrete and the properties of the lubrication layer, near the steel pipe–concrete interface, are studied by a portable rheometer and tribometer. The thickness of the lubrication layer of each concrete mixture is determined using a microindentation test method. The results show that 1% nanoclay and

Get price

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. This kind of flow state is known as friction flow and ...

Get price

Rheology of Concrete – Rheological Parameters of Fresh ...

The study of rheology of concrete provides information on properties of fresh concrete such as deformation, behavior of mix, and placement of mixed concrete. Rheology is a term that is mainly used for fluids whose flow properties are complicated in nature, other than fluids like liquids or gases. The term rheology may be defined as the study of the science of the flow and deformation of ...

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

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. As this approach is limited to CVC, a new tribometer and data treatment procedure were recently developed ...

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