Measuring Rheological Properties of Cement Pastes: Most common Techniques, Procedures and Challenges

Feys, Dimitri; Cepurītis, Rolands; Jacobsen, Stefan; Lesage, Karel; Secrieru, Egor; Yahia, Ammar

doi:10.21809/rilemtechlett.2017.43

Cited by 103 publications

(62 citation statements)

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“…The science of rheology is increasingly used to describe the properties of fresh cement paste. Compared to standard workability tests, rheological properties allow carrying out more fundamental investigation, more precise phenomenological description of flow properties and serving as input for numerical simulations [16]. However, when the cement researchers use rheometers the results depend very much on choice of protocol and tested material.…”

Section: The Choice Of the Diagnostic Methods For Injection Mortars Rhmentioning

confidence: 99%

Diagnostics and regulation of rheological characteristics for injection mortars by electromechanical sensors

et al. 2020

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In the article the diagnostic and regulation problems are considered for the rheological characteristics of mortars which are used for pumping into the interpipe gaps or cracks during repairing the pipelines, tunnels, and other objects. It is important to obtain the necessary mortar viscosity which allows providing a complete hole filling. For this aim the experimental dependencies have been determined between the injection mortar viscosity, the water-cement ratio, and the additives quantity in the mortars. According to the Poiseuille's flow law the theoretical dependencies have been obtained between the penetration depth of the injection mortar and viscosity under the different water-cement ratios. The said dependencies are a base during the development of the functioning algorithm the diagnostic and regulation system of the injection cement mortars rheological characteristics. The description of this functioning system is given. The mentioned system application allows increasing the cementation quality, corrosion resistance and durability of the repaired pipeline sections as well as decreasing of the work duration and labor costs.

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Section: The Choice Of the Diagnostic Methods For Injection Mortars Rhmentioning

confidence: 99%

Diagnostics and regulation of rheological characteristics for injection mortars by electromechanical sensors

et al. 2020

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“…Ωr h (25) wherer is the radial position, Ω is the angular velocity of the rotating plate, and h is the gap between plates. The chosen rheometer geometry was selected for the reason that it is typically used in the field [41], and it is part of the experimental setup currently being used by the authors to conduct experimental studies whose results are pending publication. Other common geometries (such as the concentric cylinders configuration) can be incorporated into the model after replacing the previous equation with a suitable shear profile.…”

Section: γ(R) =mentioning

confidence: 99%

Numerical Validation of a Population Balance Model Describing Cement Paste Rheology

Gallo-Molina

Lesage

2020

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Rheology control is essential during the period in which cement and concrete pastes are encountered in the fresh state, due to the fact that it directly affects workability, initial placement and the structural performance of the hardened material. Optimizations of clinker formulations and reductions in cement-to-water ratios induced by economic and environmental considerations have a significant effect in rheology, which invokes the need for mechanistic models capable of describing the effect of multiple relevant phenomena on the observed paste flow. In this work, the population balance framework was implemented to develop a model able to relate the transient microstructural evolution of cement pastes under typical experimental conditions with its macroscopic rheological responses. Numerical details and performance are assessed and discussed. It was found that the model is capable of reproducing experimentally observed flow curves by using measured cluster size distribution information. It is also able to predict the complex rheological characteristics typically found in cement pastes. Furthermore, a spatially resolved scheme was proposed to investigate the nature of flow inside a parallel-plates rheometer geometry with the objective of assessing the ability of the model of qualitatively predicting experimentally observed behavior and to gain insight into the effect of possible secondary flows.

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“…Inaccuracy increases as the tested sample leaves the Newtonian region. Absolute parameters using parallel-plate or cone-plate geometries provide reliable data on rheological properties, although they are only available for suspensions without coarse aggregates [39]. With cement as reactive phase and the associated structural buildup taking place as soon as the sample is at rest, the overall procedure and time steps affect the final rheological measurement.…”

Section: Rheological Measurementsmentioning

confidence: 99%

“…the last 2 s of each step. The shear stress was calculated from the torque value following geometric basics according to the Reiner-Riwlin equation [39,54]. The yield stress τ 0,B for each flow curve was calculated following the Bingham regression for the steady state between 20 rpm and 60 rpm.…”

Section: Rheological Measurementsmentioning

confidence: 99%

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L-Box Form Filling of Thixotropic Cementitious Paste and Mortar

et al. 2020

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Rheological properties of cementitious pastes and mortar affect the casting, placement, and setting properties of fresh concrete. Fundamental rheological knowledge thus helps in predicting concrete flowability and workability. Empirical equations correlate actual rheological parameters based on physical material characteristics to workability tests. Still, these equations generally only take the dynamic yield stress of the material into account. This is not sufficient for thixotropic cementitious pastes or mortars, which possess structural buildup at rest. Workability predictions regarding the flow of concrete are thus more complicated with thixotropic materials. During form-filling in L-shaped formworks, the flow velocity of concrete slows down, wherefore rheological parameters change with time. At initial fast flow, high shear rates without structural buildup can be assumed. Dynamic yield stress and a steady state viscosity thus are proper parameters for empirical equations describing concrete flowability. During low shear rates, partial structural buildup takes place. Viscosity and yield stress increase due to agglomeration and affect the flowability of concrete tremendously. Rheological parameters of various cementitious pastes and mortars varying in their solid volume fraction and flowability were investigated in a vane-in-cup rheometer. The workability of the same mixtures was investigated by measuring the flow length in an L-shaped formwork. The effect of yield stress, viscosity, and thixotropic structural buildup on flow length was investigated. Subsequently correlations and discrepancies between flowability parameters and workability equations were analyzed.

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Measuring Rheological Properties of Cement Pastes: Most common Techniques, Procedures and Challenges

Cited by 103 publications

References 50 publications

Diagnostics and regulation of rheological characteristics for injection mortars by electromechanical sensors

Diagnostics and regulation of rheological characteristics for injection mortars by electromechanical sensors

Numerical Validation of a Population Balance Model Describing Cement Paste Rheology

L-Box Form Filling of Thixotropic Cementitious Paste and Mortar

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