Pumping of concrete: Understanding a common placement method with lots of challenges

Feys, Dimitri; Schutter, Geert De; Fataei, Shirin; Martys, Nicos; Mechtcherine, Viktor

doi:10.1016/j.cemconres.2022.106720

Cited by 44 publications

(17 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The robustness of this approach improves with increasing volume fraction of spheres as a less detailed knowledge of flow of the background fluid is needed. Indeed, it has been found that at volume fractions of approximately 40 % and higher, the flows produced are reasonably consistent with fully detailed simulations [28]. This is due to the fact that, at higher volume fractions, the surfaces of the solid inclusions are close enough such that the lubrication forces dominate over the long-range hydrodynamics of the background fluid [29].…”

Section: A Simulation Detailssupporting

confidence: 65%

Ordered domains in sheared dense suspensions: the link to viscosity and the disruptive effect of friction

Goyal¹,

Gado²,

Jones³

et al. 2022

Preprint

View full text Add to dashboard Cite

Monodisperse suspensions of Brownian colloidal spheres crystallize at high densities, and ordering under shear has been observed at densities below the crystallization threshold. We perform largescale simulations of a model suspension containing over 10 5 particles to quantitatively study the ordering under shear and to investigate its link to the rheological properties of the suspension. We find that at high rates, for P e > 1, the shear flow induces an ordering transition that significantly decreases the measured viscosity. This ordering is analyzed in terms of the development of layering and planar order, and we determine that particles are packed into hexagonal crystal layers (with numerous defects) that slide past each other. By computing local ψ6 and ψ4 order parameters, we determine that the defects correspond to chains of particles in a square-like lattice. We compute the individual particle contributions to the stress tensor and discover that the largest contributors to the shear stress are primarily located in these lower density, defect regions. The defect structure enables the formation of compressed chains of particles to resist the shear, but these chains are transient and short-lived. The inclusion of a contact friction force allows the stress-bearing structures to grow into a system-spanning network, thereby disrupting the order and drastically increasing the suspension viscosity.

show abstract

Section: A Simulation Detailssupporting

confidence: 65%

Ordered domains in sheared dense suspensions: the link to viscosity and the disruptive effect of friction

Goyal¹,

Gado²,

Jones³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…The flow of concrete through closed pipes results in the formation of multiple flow zones, such as a lubricating layer, a shear zone, and a plug flow in the central area of the pipe, as shown in Figure 1. This comprehensive characterization of concrete flow behavior is considered stateof-the-art [1]. As concrete flows through a pipe, friction between the concrete and the pipe wall causes a non-uniform distribution of shear stresses across the pipe's cross-section.…”

Section: Flow Of Concrete In Pipes 21 General Description Of Concrete...mentioning

confidence: 99%

Multiphase granular suspension flow of fresh concrete during pumping in complex geometries

Mikhalev,

Kluwe,

Schwarze

et al. 2023

ce papers

Self Cite

View full text Add to dashboard Cite

During the pumping process of multiphase granular suspensions, such as concrete, through pipe systems, many parameters can influence the material's ability to flow. To understand the hydrodynamics and particle mechanics in granular, non‐Newtonian suspensions under nonlinear flow conditions, the authors have been working on a joint project within the Priority Program SPP 2005 “Opus Fluidum Futurum ‐ Rheology of Reactive, Multiscale, Multiphase Construction Materials” funded by the German Research Foundation (DFG). Based on the results obtained, it is possible to describe the relationships between concrete composition and the rheological properties of the fresh mixture for pumping applications. The effects of particle geometry and flow conditions on flow‐induced particle migration (FIPM), subsequently the formation of a lubricating layer (LL), and eventually on pumping pressure were also shown. While the behavior of concrete and other complex, multiscale suspensions in generic flows (Couette, Poiseuille) is still part of current research and only partially understood, the behavior in complex geometries is even less explored so far. Here, additional effects based on the curvature of streamlines and mass inertia of the particle phase come into play. In the framework of the project, these effects have been investigated experimentally and numerically. Various experimental approaches have been developed to observe the behavior of particles within their carrier fluid in an opaque, dense, and enclosed moving system, yielding insightful results. Currently, models are being developed and experimentally validated to describe particle migration quantitatively, allowing conclusions about the local rheological behavior to be drawn. This information is essential to predict the flow behavior necessary for modern processes such as 3D printing and energy‐optimized pumping.

show abstract

“…Domestic and foreign scholars have launched a series of research endeavours, such as rheological behaviour analysis (Le et al 2015;Xiao-Fang et al 2006;Kwon et al 2016;Feys et al 2022), pumping model construction (Hao et al 2021;Lianjun et al 2016), and pressure loss impact analysis (Chen et al 2019;Kim et al 2018;A et al 2022), focused on the rheological characteristics of concrete aggregate particles during pumping (Hu et al 2011;Geiker et al 2002;Sung et al 2014;. In terms of rheological behaviour analysis, Jo et al (2012) considered that aggregates and mortar generate a nonuniform shear field under the combined effect of the pumping pressure and pipe wall friction.…”

Section: Introductionmentioning

confidence: 99%

One-Dimensional Modelling of the Pressure Loss in Concrete Pumping and Experimental Verification

Zhao,

Gao,

Wan

et al. 2024

Preprint

View full text Add to dashboard Cite

An accurate formula with high precision for calculating the pressure loss in concrete pumping plays a significant guiding role in the design and service process of pump trucks. Based on the flow characteristics of concrete pumping, a one-dimensional model for the pressure loss was developed in which both the viscous force of the mortar in the lubrication layer and the blocking effect of coarse aggregate particles were considered. First, the complex geometrical shapes of the aggregate particles were reconstructed by using a HandySCAN noncontact 3D laser scanner and the inverse modelling software Geomagic Design X. Then, the equivalent spherical size of uneven aggregate particles was calculated according to the equal hydraulic radius principle. The blocking effect of the aggregate particles was converted into the wall roughness. Finally, an explicit expression for the pressure loss in concrete pumping was deduced by using Modi’s formula, Bernoulli’s equation and Darcy’s formula, and the calculated value was compared with the measured value at a corresponding experimental site. The results indicated that the pressure loss values calculated with the one-dimensional flow model, which are closer to the actual pumping pressure loss values, are more accurate than those obtained with a theoretical empirical formula.

show abstract

Pumping of concrete: Understanding a common placement method with lots of challenges

Cited by 44 publications

References 54 publications

Ordered domains in sheared dense suspensions: the link to viscosity and the disruptive effect of friction

Ordered domains in sheared dense suspensions: the link to viscosity and the disruptive effect of friction

Multiphase granular suspension flow of fresh concrete during pumping in complex geometries

One-Dimensional Modelling of the Pressure Loss in Concrete Pumping and Experimental Verification

Contact Info

Product

Resources

About