scholarly journals Study of cement pastes rheological behavior using dynamic shear rheometer

2014 ◽  
Vol 7 (6) ◽  
pp. 922-939
Author(s):  
J. E. S. L. Teixeira ◽  
V. Y. Sato ◽  
L. G. Azolin ◽  
F. A. Tristão ◽  
G. L. Vieira ◽  
...  
Keyword(s):  
Rheological Behavior ◽  
Scientific Community ◽  
Flow Characteristics ◽  
Bingham Fluid ◽  
Material Behavior ◽  
Rheological Parameters ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Flow Test ◽  
Fresh State

Concrete, in its fresh state, has flow characteristics that are crucial to its proper launch and densification. These characteristics are usually measured through empirical testing as the slump test, but this test does not quantify completely the material behavior. Since this material is characterized as a Bingham fluid, it is essential the study of its rheological behavior to verify its properties even in fresh state. The use of classical rheology has been employed by the scientific community to obtain rheological parameters determinants to characterize this material, such as yield stress, plastic viscosity and evolution of shear stress to shear rate. Thus, this present study aims to determine the rheological behavior of different cement pastes produced with cement CP III 40 RS, varying between them the hydration periods (20 and 60 min), the water-cement ratio (0.40, 0.45 and 0.50) and the use or not of additive. Samples were assayed by flow test to determine the rheological parameters showing the effect of the variables mentioned above in these parameters.

scholarly journals Contribution to the rheological study of cementitious pastes with addition of residues from the processing of ornamental rocks

2018 ◽  
Vol 11 (6) ◽  
pp. 1284-1307 ◽  
Author(s):  
V. Y. SATO ◽  
A. P. L. GALINA ◽  
J. E. S. L. TEIXEIRA
Keyword(s):  
Rheological Parameters ◽  
Cement Matrix ◽  
Rheological Characterization ◽  
Cement Pastes ◽  
Rheological Study ◽  
Mineral Addition ◽  
Flow Test ◽  
Ornamental Stones ◽  
Thixotropic Fluid

Abstract Brazil is one of the world's largest producers and exporters in the field of ornamental stones. On the other hand, the production and processing of ornamental stones result in a large volume of unused material in the form of sludge, usually discarded inappropriately in sedimentation ponds or landfills. Several researches have been carried out aiming the reuse of this material in cementitious matrixes. In the field of rheology, there are still incipient national studies that use the rheological parameters obtained experimentally to determine the behavior of cement matrix based on Portland cement. Thus, the objective of this work is to characterize rheologically the behavior of cementitious pastes with and without addition of ornamental rock processing residue (RBRO) in its natural condition. Cement pastes were prepared with three a/c ratios (0.45, 0.55, 0.65) and four residue addition contents (0%, 5%, 10%, 15%) and submitted to the flow test. In tests for characterization of the residue, the RBRO presented as a material of specific fineness and mass near the cement, having low reactive activity, indicating that the residue can be used as an inert mineral addition in the cementitious matrix. In the rheological characterization tests of the pulps studied, it was observed in the flow tests that the samples behaved as a non-Newtonian, pseudoplastic and thixotropic fluid.

scholarly journals Properties of Polymer Modified Concrete in Fresh and Hardened State

2013 ◽  
Vol 687 ◽  
pp. 204-212 ◽  
Author(s):  
Ioana Ion ◽  
José Barroso Aguiar ◽  
Nicolae Angelescu ◽  
Darius Stanciu
Keyword(s):  
Flexural Strength ◽  
Compression Strength ◽  
Rheological Behavior ◽  
Epoxy Resins ◽  
Microstructure Formation ◽  
Cement Ratio ◽  
Strength Tests ◽  
Fresh State ◽  
Hardened State ◽  
Polymer Modified Concrete

It was carried out a study on the properties of polymer modified concrete (PCM) in fresh and hardened state. It was used three types of polymers: epoxy resins, polyurethane and methylcellulose in different percentages and different water cement ratio. The main objectives was to improve workability and rheological behavior of these mixtures in fresh state and mechanical strength tests on hard concrete. Has been investigated the polymer influence on compression strength and flexural strength and analyzing the time evolution of these strengths and participation of polymer in the microstructure formation.

scholarly journals Evaluating the applicability of rheometry in steel fiber reinforced self-compacting concretes

2016 ◽  
Vol 9 (6) ◽  
pp. 969-988 ◽  
Author(s):  
R. S. Alferes Filho ◽  
◽  
F. K. Motezuki ◽  
R. C. O. Romano ◽  
R. G. Pileggi ◽  
...  
Keyword(s):  
Construction Industry ◽  
Steel Fiber ◽  
Rheological Parameters ◽  
Experimental Program ◽  
Test Results ◽  
Slump Flow ◽  
Flow Test ◽  
Conventional Tests ◽  
Fresh State ◽  
Passing Ability

ABSTRACT The use of self-compacting concrete in civil construction industry presents various advantages, since the material shows adequate workability during fresh state. When fiber reinforcement is used, there are changes in its behavior that require attention. This study aimed to evaluate the applicability of rheological tests and the correlation between its results and those obtained with regular tests used to control SCCs. In that sense, different mixtures of SCC with different steel fiber contents were produced in order to be analyzed in the experimental program described. Rotational rheology tests and slump flow and L-box tests were performed. The results showed that slump flow test did not present good correlations with rheological parameters. On the other hand, this test was able to point out the risk of segregation of the mixtures with higher fiber contents. A good correlation was obtained between the L-box test results and rheological parameters. The L-box was also able to show loss in the passing ability of SCC related to the rise of plastic viscosity and yield stress. These tests also presented a good correlation with the rheological parameters when lower fiber contents were used. Although the rheometry test was unable to evaluate these problems, this kind of test gave more objective and reliable data on variations in rheological parameters related to the increase of fiber content, and proved to be a more reliable test to this kind of application, especially when applied together with the conventional tests.

scholarly journals Towards an optimization of the formulation of geopolymers in the fresh state: Rheological approach

2019 ◽  
Vol 29 (1) ◽  
pp. 94-104
Author(s):  
Nouha Lahlou ◽  
Mohamed Ouazzani Touhami ◽  
Rabii Hattaf ◽  
Redouane Moussa
Keyword(s):  
Rheological Behavior ◽  
Setting Time ◽  
Structural Identification ◽  
Critical Values ◽  
Rheological Parameters ◽  
Alkaline Activation ◽  
Fresh State ◽  
Kinetics Of

Abstract In this work, we are interested in describing the evolution of the rheological behavior of geopolymer materials since their elaboration until the start of their kinetics of setting. We considered the case where these materials are obtained from the dissolution of a quantity S of metakaolin in a quantity L of alkaline activation solution (sodium-based). In this context and for all the values of the structural identification parameters P = (% Na2O) and R3 = (L/S) in our experiments, it has been established that the rheological behavior is described by the viscoplastic Herschel-Bulkley model. In particular, we have been able to determine how rheological parameters of the model are affected by variations of P and / or R3. For the considered formulations, this analysis is of importance insofar as it was at the base of the identification of critical values of P and R3. Moreover, we verified that for these values, the setting time is maximum. This result is retained to define the optimized formulation of our materials.

The rheological behavior of fresh cement pastes

1988 ◽  
Vol 18 (3) ◽  
pp. 327-341 ◽  
Author(s):  
Richard Shaughnessy ◽  
Peter E. Clark
Keyword(s):  
Rheological Behavior ◽  
Cement Pastes

Assessment of Hydration Degree of Cement in the Fly Ash-Cement Pastes Based on the Calcium Hydroxide Content

2014 ◽  
Vol 875-877 ◽  
pp. 177-182 ◽  
Author(s):  
Xiang Li ◽  
Hua Quan Yang ◽  
Ming Xia Li
Keyword(s):  
Fly Ash ◽  
Calcium Hydroxide ◽  
Cement Hydration ◽  
Ash Content ◽  
Content Increase ◽  
Hydration Degree ◽  
Equilibrium Calculation ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio

The hydration degree of fly ash and the calcium hydroxide (CH) content were measured. Combined with the equilibrium calculation of cement hydration, a new method for assessment of the hydration degree of cement in the fly ash-cement (FC) pastes based on the CH content was developed. The results reveal that as the fly ash content increase, the hydration degree of fly ash and the CH content decrease gradually; at the same time, the hydration degree of cement increase. The hydration degree of cement in the FC pastes containing a high content of fly ash (more than 35%) at 360 days is as high as 80%, even some of which hydrates nearly completely. The effect of water-cement ratio to the hydration degree of cement in the FC pastes is far less distinct than that of the content of fly ash.

scholarly journals Rheological Behavior of Fresh Cement Pastes

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 106 ◽  
Author(s):  
Francisco-José Rubio-Hernández
Keyword(s):  
Rheological Behavior ◽  
Flow Behavior ◽  
Viscoelastic Behavior ◽  
Alternative Methods ◽  
Chemical Additives ◽  
Research Activity ◽  
Cement Pastes ◽  
Blended Cements ◽  
Flow Models ◽  
Mineral Additions

Rheology of a concrete is mainly controlled by the rheological behavior of its cement paste. This is the main practical reason for the extensive research activity observed during 70 years in this research subfield. In this brief review, some areas of the research on the rheological behavior of fresh cement pastes (mixture method influence, microstructure analysis, mineral additions influence, chemical additives influence, blended cements behavior, viscoelastic behavior, flow models, and flow behavior analysis with alternative methods) are examined.

Modelling Liquid Flow Through Carbon Nanotubes

2013 ◽  
pp. 297-309
Author(s):  
Faig Bakhman Ogli Naghiyev
Keyword(s):  
Mass Transfer ◽  
Continuum Hypothesis ◽  
Flow Characteristics ◽  
Bingham Fluid ◽  
Length Scale ◽  
Review Of The Literature ◽  
Nanoscale Systems ◽  
Flow Through ◽  
Intermolecular Distances ◽  
Moving Fluid

In this paper, the structure of a liquid and character of its flow in carbon nanotube is investigated. A review of the literature and the results of experiments show that the simulation of fluid flow for nanoscale systems should be based on the continuum hypothesis taking into account the quantized character of the liquid in the length scale of intermolecular distances. Consideration of the flow characteristics allowed construction of the analogy of behavior of the liquid in a nanotube with a flow of a viscoplastic Bingham fluid. A model of mass transfer of liquid in a nanotube, based on the possibility of forming an empty interlayer between the moving fluid particles and the particles of the wall of the nanotube, is presented.

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