Test Method for Measuring the Rheological Properties of Cementitious Materials Using a Coaxial Rotational Rheometer

2020 ◽  
Author(s):  
Keyword(s):  
Rheological Properties ◽  
Cementitious Materials ◽  
Test Method ◽  
Rotational Rheometer

scholarly journals Evaluation of Micro-Mechanism and High- and Low-Temperature Rheological Properties of Disintegrated High Volume Crumb Rubber Asphalt (DHVRA)

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1145
Author(s):  
Wei Li ◽  
Sen Han ◽  
Xiaokang Fu ◽  
Ke Huang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Rheological Properties ◽  
Particle Diameter ◽  
Gel Permeation Chromatography ◽  
High Volume ◽  
Crumb Rubber ◽  
Test Method ◽  
Polar Component ◽  
Temperature Performance

The aims of this paper are to prepare disintegrated high volume crumb rubber asphalt (DHVRA) with low viscosity, good workability and low-temperature performance by adding disintegrating agent (DA) in the preparation process, and to further analyze the disintegrating mechanism and evaluated high-temperature and low-temperature rheological properties. To obtain DHVRA with excellent comprehensive performance, the optimum DA dosage was determined. Based on long-term disintegrating tests and the Fluorescence Microscopy (FM) method, the correlations between key indexes and crumb rubber (CR) particle diameter was analyzed, and the evaluation indicator and disintegrating stage division standard were put forward. Furthermore, Fourier transform infrared spectroscopy (FT-IR) and Gel Permeation Chromatography (GPC) was used to reveal the reaction mechanism, and the contact angle test method was adopted to evaluate the surface free energy (SFE). In addition, the high-temperature and low-temperature rheological properties were measured, and the optimum CR content was proposed. Results indicated that the optimum DA dosage was 7.5‰, and the addition of DA promoted the melt decomposition of CR, reduced the viscosity and improved the storage stability. The 135 °C rotational viscosity (RV) of DHVRA from mixing for 3 h could be reduced to 1.475 Pa·s, and the softening point difference was even less than 2 °C. The linear correlation between 135 °C RV and the diameter of CR particle in rubber asphalt system was as high as 0.968, and the viscosity decay rate (VDR) was used as the standard to divide the disintegrating process into a fast disintegrating stage, stable disintegrating stage and slight disintegrating stage. Compared to common rubber asphalt (CRA), DHVRA has an absorption peak at 960 cm−1 caused by trans olefin = C-H, and higher molecular weight and polar component of surface energy. Compared with CRA, although the high-temperature performance of DHVRA decreases slightly, the low-temperature relaxation ability can be greatly improved.

scholarly journals Laboratory Test to Evaluate the Resistance of Cementitious Materials to Biodeterioration in Sewer Network Conditions

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 686
Author(s):  
Amr Aboulela ◽  
Matthieu Peyre Lavigne ◽  
Amaury Buvignier ◽  
Marlène Fourré ◽  
Maud Schiettekatte ◽  
...  
Keyword(s):  
Calcium Aluminate ◽  
Standardized Test ◽  
Performance Indicator ◽  
Cementitious Materials ◽  
Test Method ◽  
Sustainable Construction ◽  
Public Health Issue ◽  
Sulfur Source ◽  
Test Protocol ◽  
Wide Range

The biodeterioration of cementitious materials in sewer networks has become a major economic, ecological, and public health issue. Establishing a suitable standardized test is essential if sustainable construction materials are to be developed and qualified for sewerage environments. Since purely chemical tests are proven to not be representative of the actual deterioration phenomena in real sewer conditions, a biological test–named the Biogenic Acid Concrete (BAC) test–was developed at the University of Toulouse to reproduce the biological reactions involved in the process of concrete biodeterioration in sewers. The test consists in trickling a solution containing a safe reduced sulfur source onto the surface of cementitious substrates previously covered with a high diversity microbial consortium. In these conditions, a sulfur-oxidizing metabolism naturally develops in the biofilm and leads to the production of biogenic sulfuric acid on the surface of the material. The representativeness of the test in terms of deterioration mechanisms has been validated in previous studies. A wide range of cementitious materials have been exposed to the biodeterioration test during half a decade. On the basis of this large database and the expertise gained, the purpose of this paper is (i) to propose a simple and robust performance criterion for the test (standardized leached calcium as a function of sulfate produced by the biofilm), and (ii) to demonstrate the repeatability, reproducibility, and discriminability of the test method. In only a 3-month period, the test was able to highlight the differences in the performances of common cement-based materials (CEM I, CEM III, and CEM V) and special calcium aluminate cement (CAC) binders with different nature of aggregates (natural silica and synthetic calcium aluminate). The proposed performance indicator (relative standardized leached calcium) allowed the materials to be classified according to their resistance to biogenic acid attack in sewer conditions. The repeatability of the test was confirmed using three different specimens of the same material within the same experiment and the reproducibility of the results was demonstrated by standardizing the results using a reference material from 5 different test campaigns. Furthermore, developing post-testing processing and calculation methods constituted a first step toward a standardized test protocol.

scholarly journals Use of helical ribbon mixer for measurement of rheological properties of fruit pulps

2013 ◽  
Vol 19 (No. 4) ◽  
pp. 148-153 ◽  
Author(s):  
P. Novotná ◽  
A. Landfeld ◽  
K. Kýhos ◽  
M. Houška ◽  
J. Strohalm
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Flow Behaviour ◽  
Rotational Rheometer ◽  
Shear Rates ◽  
Coaxial Cylinders ◽  
Helical Ribbon ◽  
Flow Behaviour Index ◽  
Average Shear ◽  
Behaviour Index

Fruit pulps contain fine particles of the flesh of the original fruit that are suspended in the fruit juice. This suspension has a tendency to settling or separation during measurements of its rheological properties in the rotational rheometer with coaxial cylinders (especially if the greater gap is used). In this case the use of a mixer is convenient. The mixer can serve as a tool for measurement of rheological properties and at the same time it can prevent the settling and it is not sensitive to the occurrence of greater particles in the measured fluid. The helical ribbon mixer was used in this work for measurement of five samples of fruit pulp. The mixer was calibrated by the use of Newtonian fluid of known viscosity (honey). The radius of the inner cylinder of hypothetical rotational rheometer was predicted from the assumption that mixer and cylinder exhibit the same torque necessary for the rotation at the same rotational speed. The average shear rate in the mixed pulp was predicted by using the relation valid for power law fluids and rheometer with coaxial cylinders. The radius (where the average shear rate was calculated) was chosen by the requirement that the shear rate would be almost independent of changes in the flow behaviour index valid for measured pulps. Firstly the flow behaviour index was predicted as a slope of torque vs. rotational speed dependence in log-log co-ordinates. It was found that the flow behaviour index varies in the range 0.2–0.3. The radius was predicted from a graph where shear rates for 0.2 and 0.3 are the same. Then the average shear rates were calculated from rotational speeds for individual flow behaviour indexes. Rheological properties measured by using a mixer correspond to those measured with a rotational rheometer with coaxial cylinders satisfactorily only in the case that the creeping flow regime was kept in the mixed fluid. The fruit pulps are strongly non-Newtonian fluids with very low values of the flow behaviour index around 0.2.

The Effect of Sulfonated Graphene on the Rheological Properties of Cement Paste

2020 ◽  
Vol 20 (12) ◽  
pp. 7495-7505
Author(s):  
Jia-Ming Wu ◽  
Guo-Jian Jing ◽  
Xiao-Lei Lu ◽  
Tian-Yu Lei ◽  
Shu-Xian Wang ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Cement Paste ◽  
Chemical Interaction ◽  
Cementitious Materials ◽  
Rheological Parameters ◽  
Physical Interaction ◽  
Mechanical And Thermal Properties ◽  
Practical Application ◽  
Sulfonated Graphene ◽  
Modified Graphene

With unique 2D nanostructures and excellent properties, graphene and its derivatives are a class of advanced nanosized reinforcements for cementitious materials. Sulfonated graphene (SG), one of the most important modified graphene materials, possesses sulfonate groups on the surface and significantly improves the mechanical and thermal properties of cement-based composites. It is important to investigate the influence of SG on cement-based materials as it is a prerequisite for practical applications. Herein, SG was prepared and introduced into cement paste to investigate its influence on the rheological properties of cement paste. With the increased addition of SG, a stable slurry was gradually obtained with low fluidity and high rheological parameters. The mechanism of the SG effect on the rheological properties of cement paste was also illustrated. Because of the high specific surface area and sulfonate groups of SG nanosheets, a large amount of flocculated structure was created by the complexing effect, chemical interaction, physical interaction and mechanical interlocking between SG and hydrated/unhydrated cement particles. Furthermore, polycarboxylate ether (PCE) superplasticizer was introduced to ensure fluidity and transportability in the practical application of SG. The results in this work lay a foundation for the practical application of modified graphene in cementitious materials.

Rheological properties of starch suspensions using a rotational rheometer fitted with a starch stirrer cell

2014 ◽  
Vol 53 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Anne Matignon ◽  
Fabrice Ducept ◽  
Jean-Marc Sieffermann ◽  
Philippe Barey ◽  
Marc Desprairies ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Rotational Rheometer
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