scholarly journals Energy Consumption of Self-Compacting Concrete during Mixing and Its Impact on the Yield Stress Measured in the Ready-Mix Concrete Plant

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
V. Arularasi ◽  
P. Thamilselvi ◽  
Siva Avudaiappan ◽  
Erick I. Saavedra Flores
Keyword(s):  
Yield Stress ◽  
Coaxial Cylinder ◽  
Rheological Parameters ◽  
Power Relationship ◽  
Rheological Parameter ◽  
Self Compacting Concrete ◽  
Power Requirement ◽  
The Cost ◽  
Ready Mixed Concrete ◽  
Cylinder Viscometer

To find the energy required during the mixing process of self-compacting concrete in a ready-mixed concrete plant and correlate the results with the yield stress of concrete. Power consumption required during the mixing of concrete is measured with a wattmeter connected to the mixing unit’s power supply. A coaxial cylinder viscometer is used to measure the yield stress of concrete. The clamp meter measures the power when the impeller rotates inside the coaxial cylinder viscometer, which is filled with concrete. When the impeller rotates in a coaxial cylinder filled with concrete, the power is measured by a clamp meter. Torque is obtained through the power relationship, which is an essential factor in determining the yield stress. The cost of a rheometer is so high that all construction industries, research institutions, and researchers cannot measure rheological parameters. Nowadays, all rheometers are automated; hence, the cost is very high. Tattersall’s approach of power requirement in mixing the concrete and calculating the yield stress reduces the complexity in determining the rheological parameter.

Influence of Superplasticizer and Water Cement Ratio on Rheological Characteristics of Fresh Self-Compacting Concrete

2014 ◽  
Vol 893 ◽  
pp. 602-605
Author(s):  
Yang Zhou ◽  
Jian Jun Shi ◽  
Quan Liu ◽  
Jian Xin Li
Keyword(s):  
Yield Stress ◽  
Rheological Parameters ◽  
Rheological Characteristics ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Basic Parameters ◽  
The Relationship ◽  
Optimum Water

Yield stress and plastic viscosity are two basic parameters to describe the rheological characteristics of self-compacting concrete which would reflect the workability of self-compacting concrete quantificationally, the relationship between workability test results and rheological parameters was summarized, and the influence of superplasticizer and water cement ratio on rheological characteristics and of self-compacting concrete was studied by series experiments, the optimum water cement ratio and mixing amount of superplasticizer was proposed, this would guide the design and application of self-compacting concrete.

Thermorheological Characterization of Elastoviscoplastic Carbopol Ultrez 20 Gel

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. A. Hassan ◽  
Manabendra Pathak ◽  
Mohd. Kaleem Khan
Keyword(s):  
Experimental Investigation ◽  
Yield Stress ◽  
Elastic Properties ◽  
Viscous Dissipation ◽  
Power Law ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Frequency Range ◽  
Power Law Index

The temperature and concentration play an important role on rheological parameters of the gel. In this work, an experimental investigation of thermorheological properties of aqueous gel Carbopol Ultrez 20 for various concentrations and temperatures has been presented. Both controlled stress ramps and controlled stress oscillatory sweeps were performed for obtaining the rheological data to find out the effect of temperature and concentration. The hysteresis or thixotropic seemed to have negligible effect. Yield stress, consistency factor, and power law index were found to vary with temperature as well as concentration. With gel concentration, the elastic effect was found to increase whereas viscous dissipation effect was found to decrease. Further, the change in elastic properties was insignificant with temperature in higher frequency range of oscillatory stress sweeps.

Effect of chemical admixtures on the sulfate requirement of cement

1980 ◽  
Vol 7 (2) ◽  
pp. 256-263 ◽  
Author(s):  
M. A. Ward ◽  
S. M. Khalil ◽  
B. W. Langan
Keyword(s):  
Portland Cement ◽  
Initial Temperature ◽  
Precast Concrete ◽  
Steam Curing ◽  
Sulfate Content ◽  
Chemical Admixtures ◽  
Cost Of Energy ◽  
Hot Weather ◽  
The Cost ◽  
Ready Mixed Concrete

As the cost of energy and hence the cost of producing Portland cement increase, the question arises as to whether we are obtaining optimum performance from the admixtures we use. As an example, data are presented indicating that a significant improvement in strength and shrinkage can be achieved by optimizing the sulfate content of the cement for given cement–admixture combinations. It is shown that the optimum SO3 is clearly a function of the initial temperature of the concrete, particularly during the first 24 h after casting, a characteristic of considerable importance in hot weather concreting and steam curing of concrete products. It is recommended that more attention be directed towards optimizing the effectiveness of chemical admixtures in both the ready-mixed concrete and precast concrete industries.

Influence of Ground Slag on the Rheology of Mortar

2013 ◽  
Vol 438-439 ◽  
pp. 67-71
Author(s):  
Qian Qian Zhang ◽  
Jian Zhong Liu ◽  
Jia Ping Liu
Keyword(s):  
Film Thickness ◽  
Specific Surface ◽  
Yield Stress ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Film ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Water Film Thickness ◽  
Binder Ratio

The effects of ground slag with different specific surface area on the rheology of mortar at water-binder ratio of 0.25, 0.28 and 0.30 were investigated, and the combined effects of packing density and solid surface area on the rheology of mortar were evaluated in terms of the water film thickness. The results show that with the increasing of specific surface area of slag (220 m2/kg-784 m2/kg), plastic viscosity and yield stress decrease. The correlations of yield stress and plastic viscosity to the water film thickness are basically linear with high correlation R2 values. The action of the ground slag on the rheology of mortar can be characterized by water film thickness, and with the increasing of water film thickness the rheological parameters decrease.

A rotational double coaxial cylinder viscometer

1972 ◽  
Vol 11 (3-4) ◽  
pp. 275-285 ◽  
Author(s):  
B. Enoksson
Keyword(s):  
Coaxial Cylinder ◽  
Cylinder Viscometer

scholarly journals Effect of Pre-Shear on Agglomeration and Rheological Parameters of Cement Paste

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2173
Author(s):  
Mareike Thiedeitz ◽  
Inka Dressler ◽  
Thomas Kränkel ◽  
Christoph Gehlen ◽  
Dirk Lowke
Keyword(s):  
Yield Stress ◽  
Mixing Time ◽  
Length Distribution ◽  
Chord Length ◽  
Rheological Parameters ◽  
Reflectance Measurement ◽  
Time Dynamic ◽  
Chord Length Distribution ◽  
In Situ Investigation

Cementitious pastes are multiphase suspensions that are rheologically characterized by viscosity and yield stress. They tend to flocculate during rest due to attractive interparticle forces, and desagglomerate when shear is induced. The shear history, e.g., mixing energy and time, determines the apparent state of flocculation and accordingly the particle size distribution of the cement in the suspension, which itself affects suspension’s plastic viscosity and yield stress. Thus, it is crucial to understand the effect of the mixing procedure of cementitious suspensions before starting rheological measurements. However, the measurement of the in-situ particle agglomeration status is difficult, due to rapidly changing particle network structuration. The focused beam reflectance measurement (FBRM) technique offers an opportunity for the in-situ investigation of the chord length distribution. This enables to detect the state of flocculation of the particles during shear. Cementitious pastes differing in their solid fraction and superplasticizer content were analyzed after various pre-shear histories, i.e., mixing times. Yield stress and viscosity were measured in a parallel-plate-rheometer and related to in-situ measurements of the chord length distribution with the FBRM-probe to characterize the agglomeration status. With increasing mixing time agglomerates were increasingly broken up in dependence of pre-shear: After 300 s of pre-shear the agglomerate sizes decreased by 10 µm to 15 µm compared to a 30 s pre-shear. At the same time dynamic yield stress and viscosity decreased up to 30% until a state of equilibrium was almost reached. The investigations show a correlation between mean chord length and the corresponding rheological parameters affected by the duration of pre-shear.

Workability tests and rheological parameters in self-compacting concrete

2008 ◽  
Vol 42 (7) ◽  
pp. 947-960 ◽  
Author(s):  
R. Zerbino ◽  
B. Barragán ◽  
T. Garcia ◽  
L. Agulló ◽  
R. Gettu
Keyword(s):  
Rheological Parameters ◽  
Self Compacting Concrete

Flow behaviour of low solids fresh cheeses

1993 ◽  
Vol 60 (4) ◽  
pp. 593-601 ◽  
Author(s):  
Jozef Korolczuk
Keyword(s):  
Shear Rate ◽  
Initial Level ◽  
Coaxial Cylinder ◽  
Initial Value ◽  
Exponential Equation ◽  
Final Stress ◽  
Final Yield ◽  
Time Required ◽  
Rate Relation ◽  
Cylinder Viscometer

SummaryA computerized, coaxial cylinder viscometer, controlled by a function synthesizer, was used to study the stress characteristics of acid fresh cheeses containing 7·5–8·5% protein and 0–20% fat in total solids, as a function of shearing time (0–3600 s) and of shear rate (0–4·5 s–1). For a given shear rate the stress diminished with time, following an exponential equation. The hypothetical final stress level (Sf for the shearing time t = ∞) represented about half its initial value (Si). For four cheese samples, the time required for the stress to become equal to Sf + (Sf – Sf)/e was 340–560 s. The stress-shear rate relation indicated shear thinning behaviour. The effect of shearing time showed that the material was thixotropic. The cheeses exhibited plastic flow. The initial and final stress levels were hyperbolic functions of the shear rate. Bingham final yield stress (for t = ∞) was 14–50 Pa. It was 15–25% higher for increasing than for decreasing shear rate. Bingham viscosity (for t = ∞) was between 2 and 6 Pa s. It was 10–20% higher for decreasing shear rate. The initial level of Bingham viscosity was ˜ 30% higher than its final value.

Sensory Evaluation and Rheological Behavior of Commercial Mayonnaise

2007 ◽  
Vol 3 (1) ◽  
Author(s):  
Dayane Izidoro ◽  
Maria-Rita Sierakowski ◽  
Nina Waszczynskyj ◽  
Charles W. I. Haminiuk ◽  
Agnes de Paula Scheer
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Sensory Evaluation ◽  
Rheological Behavior ◽  
Oil Content ◽  
Sensory Attributes ◽  
Rheological Parameters ◽  
Low Fat ◽  
Concentric Cylinder ◽  
Rheological Characterization

The effects of ingredients on the sensory evaluation and rheological behavior of two brands of mayonnaise were examined in this work. Mayonnaise samples were examined by Analytical Descriptive Test and Ranking Test of Preference. The rheological parameters were determined at 25°C using a concentric cylinder Brookfield rheometer with a spindle SC4-34. The results showed that standard mayonnaise as opposed to low-fat mayonnaise gained higher grades for most sensory attributes. All samples were found to exhibit non-Newtonian pseudoplastic behavior described by Herschel–Bulkley model. A decrease in the yield stress, viscosity and shear stress with the decrease in oil content was observed in all products, which confirm that the rheological characterization is capable of distinguishing rather well between mayonnaises made with different formulation.

Sign in / Sign up

Export Citation Format

Share Document