INFLUENCE OF VISCOSITY ENHANCING AGENT ON RHEOLOGY AND COMPRESSIVE STRENGTH OF SUPERPLASTICIZED MORTARS

2009 ◽  
Vol 15 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Jacek Gołaszewski
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Plastic Viscosity ◽  
Basic Relation ◽  
Rheological Parameters ◽  
Bingham Model ◽  
Yield Value

The results of investigation into the influence of Viscosity Enhancing Agents (VEA) on the rheological properties of mortars, different in cement and superplasticizer properties, are presented and discussed. Rheology results have been evaluated according to the Bingham model, which describes the rheology with 2 parameters: yield value and plastic viscosity. Rheological parameters were measured using Two‐Point Workability Test (TPWT). Additionally, the influence of VEA on compressive strength of mortars is presented. It was found that effects of VEA addition on rheological properties of mortars, as well as on compressive strength of mortars, significantly depend on cement and superplasticizer properties. Basic relation of influence of VEA on rheological properties and compressive strength of mortars in respect to cement and superplasticizer properties were presented and discussed. It is concluded that addition of VEA influences compatibility between cement and superplasticizer. Because addition of VEA may cause decrease in compressive strength, the assessment of compatibility of VEA ‐ cement ‐ superplasticizer system should be performed in relation not only to rheological properties, but also to compressive strength. Santrauka Straipsnyje pateikta ir išanalizuota klampą didinančių priedų įtaka skiedinių reologinėms savybėms. Skiediniai buvo ruošiami su įvairių savybių cementais ir superplastikliais. Reologijos tyrimų rezultatai įvertinti remiantis Binghamo modeliu. Reologinės savybės buvo tiriamos dviejų parametrų reometru (TPWT). Taip sudarytas naturalus šviežio skiedinio ir betono mišinio reologinės elgsenos būvis. Straipsnyje taip pat pateikti klampą didinančių priedų įtakos betono stipriui giuždant rezultatai. Nustatyta, kad klampą didinančių priedų poveikio efektas skiedinių reologinėms savybėms ir stipriui gniuždant iš esmės priklauso nuo cemento ir superplastiklių savybių.

scholarly journals Influence of polymer fibers on rheological properties of cement mortars

2017 ◽  
Vol 7 (1) ◽  
pp. 228-236 ◽  
Author(s):  
Dorota Malaszkiewicz
Keyword(s):  
Rheological Properties ◽  
Volume Fraction ◽  
Fiber Type ◽  
Cementitious Materials ◽  
Plastic Viscosity ◽  
Synthetic Fiber ◽  
Rheological Parameters ◽  
Model Parameters ◽  
Fine Aggregate ◽  
Bingham Model

AbstractThe reinforcing effect of fibers in cement composites often results in the improvement of the brittle nature of cementitious materials. But the decrease in the workability of fresh concrete is often the disadvantage of fibers addition. Conventional single-point workability tests cannot characterize workability of concrete in terms of fundamental rheological parameters. To this end, this paper describes an investigation of the influence of synthetic fiber additions (fiber length in the range 12–50 mm and volume fraction in the range 0–4%) on the rheological properties of fiber reinforced fresh mortar (FRFM) and development of these properties over time. The rheometer Viskomat XL was used in this study. Within the limitations of the instrument and testing procedure it is shown that FRFMs conform to the Bingham model. Natural postglacial sand 0/4 mm was used as a fine aggregate and cement CEMI 42.5 R was used as a binder. Three commercial synthetic fibers were selected for these examinations. Rheological properties were expressed in terms of Bingham model parameters g (yield value ) and h (plastic viscosity). Based on the test results it was found out that the fiber type and volume fraction affected both the yield stress and plastic viscosity.

scholarly journals Effect of Calcareous Fly-ash Processing Methods on Rheological Properties of Mortars

2018 ◽  
Author(s):  
Jacek Gołaszewski ◽  
Zbigniew Giergiczny ◽  
Tomasz Ponikiewski ◽  
Aleksandra Kostrzanowska-Siedlarz ◽  
Patrycja Miera
Keyword(s):  
Fly Ash ◽  
Rheological Properties ◽  
Negative Influence ◽  
Plastic Viscosity ◽  
Processing Methods ◽  
Yield Value ◽  
Selective Collection

The paper presents the results of research into the influence of calcareous fly ash (CFA) processing methods on the rheological properties of mortars. The study consisted of a comparison of changes of the rheological properties (plastic viscosity and yield value) of the mortars during 90 minutes when CFA, unprocessed or processed by grinding, grain separation, or selective collection from the filter, was used as a substitute for a part of the cement. The results show that processing of CFA decreases its negative influence on the rheological properties; the efficient methods are separation or grinding, while the effect of selective collection is almost insignificant.

Influences of Micropowder Gradation on Rheological Properties of Cement-Based Composite Pastes

2007 ◽  
Vol 353-358 ◽  
pp. 1398-1401
Author(s):  
Jian Qing Gong ◽  
Han Ning Xiao ◽  
Zheng Yu Huang ◽  
Jiu Su Li ◽  
Jing Nie ◽  
...  
Keyword(s):  
Shear Stress ◽  
Rheological Properties ◽  
Packing Density ◽  
High Performance ◽  
High Performance Concrete ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Ultra High Performance Concrete ◽  
Cement Pastes ◽  
Compressible Packing Model

The rheological parameters of cement pastes were investigated by varying the type and content of micropowders and the ratio of water to binder. Compressible packing model was used to calculate the packing density and to evaluate the influence of micropowders gradation on the rheological properties of fresh cement pastes. Results indicate that the higher the packing density is, the lower the yielding shear stress and plastic viscosity will be. When the ratio of water to binder is less than 0.20, the cement paste with 15% UFA and 15% SF has highest packing density and lowest yielding shear stress and plastic viscosity, which is beneficial to the workability of ultra-high performance concrete.

scholarly journals CRITERIONAL FEATURES OF STRUCTURAL CHARACTERISTICS OF FINE TEXTILE MEAT

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
М. П. Сичевський ◽  
Л Войцехівська ◽  
К В Копилова ◽  
C Б Вербицький ◽  
Ю І Охріменко
Keyword(s):  
Shear Stress ◽  
Rheological Properties ◽  
Maximum Shear Stress ◽  
Fat Content ◽  
Plastic Viscosity ◽  
Poultry Meat ◽  
Rheological Parameters ◽  
Limit Values ◽  
Mechanically Separated Meat ◽  
Minced Meat

Poultry meat mechanically separated from broiler carcasses and compared with minced meat from manual deboning was studied. It has been found that an increase in the free moisture content of mechanically separated meat by 10-15% causes a reduction in shear characteristics by almost 2 times. The shear stress values ​​in hand-rolled meat samples were, on average, 1.3 times higher than in physico-chemically similar samples of mechanically separated meat. The samples of hand-rolled meat differed by 1.4 times the values ​​of plastic viscosity, as well as larger, on average 1.5 times, the values ​​of the coefficient of consistency. A set of rheological parameters and their limit values, close to the characteristics of minced meat from manual deboning, namely: the maximum shear stress (penetration) - from 1.9 kPa to 2.2 kPa; plastic viscosity - from 33 Pa • s to 45 Pa • s; coefficient of consistency - from 1.4 to 1.7. It has been established that the most important factors influencing the difference between the rheological parameters of mechanically separated meat and hand-rolled meat are the fat content and the degree of grinding. The reduction of fat content, processing pressure, as well as the speed of grinding of raw materials allows to bring the rheological characteristics of mechanically separated meat to the characteristics of manual deboning meat. The nature of the change in the rheological properties of meat mechanically separated over time is revealed: during the first stage (lasts about 2-3 hours) the structure remains unchanged, the second stage is the period of growth of all indicators to the maximum value, this is the period of critical aging. Further aging (third period) is characterized by a decrease in the numerical values ​​of all indicators, due to a decrease in the strength of the structure under the action of a complex of microbiological and biochemical processes. The study of the rheological properties of mechanically separated meat of broiler chickens and the comparison of the obtained indicators with the corresponding characteristics of minced meat formed by mincing hand-rolled meat, gave grounds for concluding on the possibility and expediency of mechanically separated meat in meat products.

scholarly journals Analysis of the Effect of Various Types of Limestone as a Main Constituent of Cement on the Chosen Properties of Cement Pastes and Mortars

2019 ◽  
Vol 65 (3) ◽  
pp. 75-86
Author(s):  
J. Gołaszewski ◽  
G. Cygan ◽  
M. Gołaszewska
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Yield Stress ◽  
Drying Shrinkage ◽  
Plastic Viscosity ◽  
Main Constituent ◽  
Cement Pastes ◽  
Mortar Strength ◽  
The Impact

AbstractThe article is an attempt to compare the impact of the use of various types of limestone as the main constituent of cement on selected mortar properties. Four different limestones were added in amount of 15, 30, 40% to CEM I 42.5 R to obtain limestone cemens. Rheological properties (yield stress, plastic viscosity) of fresh mortar, tensile and compressive mortar strength, early shrinkage, and drying shrinkage were tested. Obtained results indicate that both tensile and compressive strength decreases with the increase of the limestone content in cement. Limestone can worsen or improve workability, depending on distribution of limestone grains. The addition of limestone increases the early shrinkage, but reduces the shrinkage after 28 days. Studies show that the granulation of limestone plays an important role in determining the influence of limestone on mortar properties.

scholarly journals Effect of Silica Fume on the Rheological Properties of Cement Paste with Ultra-Low Water Binder Ratio

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 554
Author(s):  
Juan He ◽  
Congmi Cheng ◽  
Xiaofen Zhu ◽  
Xiaosen Li
Keyword(s):  
Hysteresis Loop ◽  
Rheological Properties ◽  
Yield Stress ◽  
Silica Fume ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Loop Area ◽  
Binder Ratio ◽  
Hysteresis Loop Area ◽  
Water Binder Ratio

The effect of silica fume on the rheological properties of a cement–silica fume–high range water reducer–water mixture with ultra-low water binder ratio (CSHWM) was studied. The results indicate that the W/B ratio and silica fume content have different effects on the rheological parameters, including the yield stress, plastic viscosity, and hysteresis loop area. The shear-thickening influence of CSHWM decreased with the increased silica fume content. When the silica fume content increased from 0% to 35%, the mixture with W/B ratio of 0.19 and 0.23 changed from a dilatant fluid to a Newtonian fluid, and then to a pseudoplastic fluid. When the silica fume content was less than 15%, the yield stress was close to 0. With the increase of silica fume content, the yield stress increased rapidly. The plastic viscosity and hysteresis loop area decreased slightly with the addition of a small amount of silica fume, but increased significantly with the continuous increase of silica fume. Compared with the Bingham and modified Bingham models, the Herschel–Buckley model is more applicable for this CSHWM.

Experimental Research on Rheological Properties of Cemented Mortar in Tail Void Grouting of Shield Tunnel

2011 ◽  
Vol 261-263 ◽  
pp. 1201-1205 ◽  
Author(s):  
Xiao Hui Yuan ◽  
Yue Wang Han
Keyword(s):  
Rheological Properties ◽  
Flow Pattern ◽  
Yield Stress ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Shear Yield Stress ◽  
Shear Yield ◽  
Binder Ratio ◽  
Water Ratio ◽  
Water Binder Ratio

Grout flow pattern and rheological parameters determine grouting pressure transfer process in annular tail void and filling rate for shield tail void. However, cemented mortar is a mixture of cement, fly ash, sand, bentonite and water, which lead to grout rheological properties and rheological parameters are difficultly determined. Based on orthogonal experimental design method, grout rheological properties were tested by rotational viscometer. Utilizing variance and poly-nonlinear regression analysis, the qualitative and quantitative relationships between mix ratios and rheological parameters were obtained respectively. It is shown that cemented mortar flow pattern commonly agree with Bingham fluid type, and plastic viscosity varies between 1 and 4Pa•s, and shear yield stress varies between 10 to 40Pa respectively. Water-binder ratio and bentonite-water ratio are key influencing factors for grout rheological parameters. With the water-binder ratio increasing and bentonite-water ratio decreasing, plastic viscosity and shear yield stress present reducing tendency.

scholarly journals The Effect of the Activator/Precursor Ratio on the Rheological Properties of the Alkali-activated Mining Waste Mud Paste

2020 ◽  
Author(s):  
Abdelhakim Benhamouda ◽  
João Castro-Gomes ◽  
Luiz Pereira-de-Oliveira
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Rheological Properties ◽  
Yield Stress ◽  
Rheological Behaviour ◽  
Mining Waste ◽  
Bingham Model ◽  
Precursor Ratio ◽  
Alkali Activated ◽  
The Ideal

To determine the properties of paste, mortar or concrete, it is necessary to understand its rheological behaviour first. This study discusses the effect of the activator/precursor ratio on the rheological properties of the alkali-activated paste. The pastes consisted of a mix of 70 % of tungsten mining waste mud, 15% waste glass and 15% of metakaolin. This mix was activated by combining sodium hydroxide and sodium silicate. Five activator/precursor (a/p) ratios were studied: 0.37, 0.38, 0.39, 0.40 and 0.41. The result obtained shows that the rheology of the pastes is affected by the activator/precursor ratio. The rheological behaviour of the paste fits the Bingham model. The yield stress (τ0) and plastic viscosity (μ) increase inversely with the activator/precursor ratio (e.g. a/p=0.37 gives τ0=84.19 and μ=0.4185; a/p=0.41 gives τ0=30.389 and μ=0.2937). The workability increases proportionally with the activator/precursor ratio (e.g. a/p=0.37 gives a slump=133 mm; a/p=0.41 gives a slump=158 mm). The compressive strength decreases when the activator/precursor ratio increases (e.g. at 28 days for a/p=0.37, the compressive strength was 19.6 MPa; for a/p=0.41, the compressive strength was 13 MPa). Finally, the ideal ratios were 0.38 and 0.39.

scholarly journals Thermophysical and rheological properties of dulce de leche with and without coconut flakes as a function of temperature

2013 ◽  
Vol 33 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Vanessa Camarinha Barbosa ◽  
Edwin Elard Garcia-Rojas ◽  
Jane Sélia dos Reis Coimbra ◽  
Paula de Aguiar Cipriano ◽  
Eduardo Basílio de Oliveira ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Rheological Properties ◽  
Plastic Viscosity ◽  
Specific Mass ◽  
Bingham Model ◽  
Total Solids ◽  
Newtonian Behavior

Dulce de leche (DL), a dairy dessert highly appreciated in Brazil, is a concentrated product containing about 70% m/m of total solids. Thermophysical and rheological properties of two industrial Brazilian Dulce de leche formulations (classic Dulce de leche and Dulce de leche added with coconut flakes 1.5% m/m) were determined at temperatures comprised between 28.4 and 76.4 °C. In general, no significant differences (p < 0.05) were observed in the presence of coconut flakes in the two formulations. Heat capacity varied from 2633.2 to 3101.8 J/kg.°C; thermal conductivity from 0.383 to 0.452 W/m.°C; specific mass from 1350.7 to 1310.7 kg/m³; and, thermal diffusivity from (1.082 × 10-7 to 1.130 × 10-7) m²/s. The Bingham model was used to properly describe the non-Newtonian behavior of both formulations, with yielding stress values varying from 27.3 to 17.6 Pa and plastic viscosity from 19.9 to 5.9 Pa.s.

scholarly journals The effect of calcite and blast furnace slag on the rheology properties of self-compacting concrete in meso and macro scales

2021 ◽  
Vol 20 (1) ◽  
pp. 190-204
Author(s):  
Murat Gokce ◽  
◽  
Osman Şimşek ◽  
Keyword(s):  
Blast Furnace ◽  
Rheological Properties ◽  
Blast Furnace Slag ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Self Compacting Concrete ◽  
Slump Flow ◽  
Macro Scale ◽  
Furnace Slag ◽  
Flow Consistency

In this study, the effects of blast furnace slag (BFS) and calcite on rheological properties of self-compacting concrete (SSC) in meso and macro scales were investigated. During the preparation of replicate samples, while BFS was replaced with the cement at the rate of 10%, 20%, 30%, and 40% by weight, calcite was added to the cement at the rate of 10%, 15%, 20%, and 25% by weight. The rheological properties (plastic viscosity and yield point) and mini-slump flow values of the cement paste prepared in meso scales were determined. The fresh flow consistency of concrete prepared in macro-scale was tested with L-box flowing test. As a result, upon evaluating the rheological parameters of the pastes according to the Bingham model, while the pastes with a plastic viscosity value close to 1 Pa·s (±100 MPa·s) and a mini-slump flow rate higher than 200 mm were observed to be more resistant to segregation and form a homogeneous flow consistency, their L-box flowing rates were determined to be homogeneous and high. Ideal SSCs were made by adding 20% and 25% calcite to 30% BFS and 40% BFS replaced mixtures respectively in this study. It was also concluded that ideal SCC could be produced with paste mixtures having 1 Pa·s (±100 MPa·s) viscosity and mini-slump flow diameter higher than 200 mm. With the increase in calcite addition rates in SSCs, the passing rate for the L box test has increased

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