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Concrete remains a widely used material in construction. As structures become more optimised, a deeper understanding of the rheology of the concrete mixture is necessary. This paper aims to numerically simulate the flow of fresh concrete in the L-box apparatus, with the objective of gaining insights into its rheological behaviour and predicting its properties. The fresh concrete flowing through the L-box test is simulated from the moment that the gate is lifted until the stoppage and the material takes its final shape. The flow in this tool occurs on a free surface. In this work, a three-dimensional model has been developed using the computational fluid dynamics technique for simulation. The flow behaviour of fresh concrete was assumed to be non-Newtonian following the Bingham law, characterised by a non-linear shear stress–shear rate ratio, yield stress and plastic viscosity. A set of numerical simulations by varying workability were conducted. Furthermore, a parametric study was conducted to examine the impact of introduced parameters in the concrete flow, including the effect of yield stress, viscosity and density. [ABSTRACT FROM AUTHOR]

The objective of this work was to study fresh concrete flow in the L-box test, predict the final deposit shape after flow stoppage and estimate the yield stress. This is very useful for controlling concrete casting in real structures, detecting problems and developing solutions on time. Concrete rheometers used for measuring the rheological parameters of concrete are expensive, not always available and can lead to measurement disparity. To overcome these issues, an effective method is to analyse concrete flow phenomena physically and solve the problem analytically based on L-box measurements. In the first part of this work, fresh concrete was considered as a homogeneous yield stress fluid moving under the effect of its self-weight. By developing momentum equations for an incompressible fluid, a theoretical approach was used to study three probable final shapes depending on the concrete rheology. Expressions were established for predicting the final shape and the yield stress. In the second part, the results obtained were compared with those of previous models and good agreement was found, thus validating the proposed approach. This study provides a consolidation of rheometer results, allowing evaluation and perhaps a calibration to reinforce their validity. [ABSTRACT FROM AUTHOR]

Abstract: This contribution is concerned with the development of a computational method for simulating the propagation of a liquefied soil, modelled as a Bingham material, while evaluating its effects on adjacent structures. The method is based upon the existence of a minimum principle for the velocity field governing the instantaneous evolution of the liquefied soil mass, which is solved by resorting to a specific numerical algorithm implemented within the context of a finite element formulation. Making use of simplifying assumptions, the calculation of the drag force induced by the moving soil mass on structures schematized as rigid obstacles, can be performed independently, exploiting the same numerical tool. The whole procedure is illustrated on the typical example of a liquefied soil embankment interacting with a single row of regularly spaced foundation piles placed across the propagating soil mass. [Copyright &y& Elsevier]