1、Designation: C1749 17aStandard Guide forMeasurement of the Rheological Properties of HydraulicCementious Paste Using a Rotational Rheometer1This standard is issued under the fixed designation C1749; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This guide covers description of several methods tomeasure the rheological properties of
3、fresh hydraulic cementpaste. All methods are designed to determine the yield stressand plastic viscosity of the material using commerciallyavailable instruments and the Bingham model. Knowledge ofthese properties gives useful information on performance ofcement pastes in concrete.1.2 The values stat
4、ed in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action. This document cannot replace education orexperience and shoul
5、d be used in conjunction with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor should thisdocument be ap
6、plied without consideration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
7、 is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization
8、 established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C305 Practice for Mechanical Mixing of Hydraulic CementPa
9、stes and Mortars of Plastic ConsistencyC511 Specification for Mixing Rooms, Moist Cabinets,Moist Rooms, and Water Storage Tanks Used in theTesting of Hydraulic Cements and ConcretesC1738 Practice for High-Shear Mixing of Hydraulic CementPastesE2975 Test Method for Calibration or Calibration Verifica
10、-tion of Concentric Cylinder Rotational Viscometers2.2 Other Standards:API Recommended Practice 10B Testing Well Cements,American Petroleum Institute, Washington, DC (1997)ISO 10426-2 (2003) Petroleum and Natural Gas IndustriesCements and Materials for Well CementingPart 2:Testing of Well CementsSec
11、tion 5.23. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology C125 and C219.3.2 Definitions of Terms Specific to This Standard:3,43.2.1 apparent viscosity, nthe shear stress divided by rateof shear, in units of Pa.s.3.2.2 plastic viscosity, nin the plast
12、ic (Bingham) model,the slope of the shear stress shear rate curve, in units of Pa.s.3.2.3 thixotropy, na decrease of the apparent viscosityunder constant shear stress or shear rate followed by a gradualrecovery when the stress or shear rate is removed.3.2.4 yield stress, nthe stress corresponding to
13、 the transi-tion from elastic to plastic deformation, in units of Pa; it is alsoreferred to as the stress needed to initiate flow. It would becalculated using the Bingham model in this guide.1This guide is under the jurisdiction of ASTM Committee C01 on Cement andis the direct responsibility of Subc
14、ommittee C01.22 on Workability.Current edition approved May 1, 2017. Published May 2017. Originallyapproved in 2012. Last previous edition approved in 2017 as C1749 17. DOI:10.1520/C1749-17A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
15、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3H.A. Barnes, J.F. Hutton and K. Walters, An Introduction to Rheology, Elsevier(1989).4Hackley V.A., Ferraris C.F., “The Use of Nomenclature in Dispersion Scienceand Tech
16、nology” NIST Recommended Practice Guide, SP 960-3, 2001.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with inter
17、nationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.5 Bingham model, na rheological model for ma
18、terialswith non-zero yield stress and a linear relationship betweenshear rate and shear stress, following the equation: = B+pl; where BYield stress in Pa, Shear rate in 1/s, Shearstress in Pa, and plPlastic viscosity in Pa.s.4. Significance and Use4.1 Rheological properties determined using this gui
19、de in-clude plastic viscosity and yield stress as defined by theBingham model and apparent viscosity.4.2 Rheological properties provide information about theworkability of hydraulic cementitious paste. As an example,the yield stress and plastic viscosity indicate the behavior of aspecific cement pas
20、te composition. As another example, theapparent viscosity indicates what energy is required to movethe suspension at a given strain rate. This test may be used tomeasure flowability of a cement paste or the influence of aspecific material or combination of materials on flowability.4.3 Rheological pr
21、operties may be sensitive to the proce-dure being used. This guide describes procedures that areexpected to provide reproducible results.5. Summary of Guide5.1 This guide provides procedures for the determination ofrheological properties of fresh cement paste using a rotationalrheometer with geometr
22、ies, such as parallel plate, narrow-gapand wide gap concentric cylinders.6. Interferences6.1 Rheological properties may be sensitive to theprocedure, so a comparison of properties obtained usingdifferent procedures is not recommended, unless relative vis-cosity (ratio between the plastic viscosity o
23、f a materials and theplastic viscosity of a reference material, both measured usingthe same rheometer) is considered.6.2 Rheological properties may be sensitive to the shearhistory of the sample, so comparison of properties usingdifferent mixing procedures is not recommended.6.3 Paste mixtures (wate
24、r and cement particles) that are veryfluid may yield erroneous data using this procedure due tosettling of particles. Such settling is especially likely in shearthinning and thixotropic mixtures.6.4 Larger cement particles or aggregations of cementparticles may block flow in a narrow-gap rheometer a
25、ndthereby increase the shear stress. The gap between the shearingsurfaces needs to be selected with consideration of the particlesize of the material to be tested. Depending on the gap size, itmay be necessary to remove larger particles by sieving orotherwise prevent segregation.6.5 Incorporation of
26、 air in the paste during mixing reducesviscosity and increases flow.6.6 The time of testing after initial contact of cement withwater influences the results.7. Apparatus7.1 General Description:7.1.1 The apparatus shall be a rotational rheometer in whichthe sample is confined between two surfaces (ca
27、lled theshearing surfaces), one of which is rotating at a constantrotational speed, and the other being stationary. The appa-ratus shall measure both the rotational speed and the torquerequired to maintain that speed.7.1.2 The rheometer geometry shall provide a simple shear-ing flow (laminar, withou
28、t turbulence). Allowable geometriesand their equations for computing stress and strain rate fromthe measured values of rotational speed and torque are de-scribed in 7.4.7.2 The rotational rheometer shall be capable of measuringshear stress at strain rates in the range from 0.1 s-1to 600 s-1.The rang
29、e of shear rates will be selected by the operatordepending on the geometry used. At least five measurementsneed to be recorded.NOTE 1Most experiments found in the literature do not use the fullrange of shear rates prescribed here. For example, most parallel platemeasurements are done between 0.1 s-1
30、to 50 s-1. The selection of theshear rate range might take into account the exact geometry of therheometer.7.3 Regularly check the calibration and zeroing of theapparatus, as discussed in 7.9.7.4 Rheometer Geometry:7.4.1 The rheometer geometries described in this sectionprovide simple shearing flow,
31、 essential for reliable computa-tion of stress and strain rates. The equation for computation ofstress and strain rates is given for each geometry.NOTE 2The following assumptions were made to develop the equa-tions that appear in this section: (1) the fluid is homogeneous, (2) slip atthe wall is neg
32、ligible, and (3) the flow regime is laminar.7.4.2 Selection of the geometry of the rheometer. Threegeometries are described here: narrow-gap concentriccylinders, wide-gap concentric cylinders, and parallel plates.The selection of the geometry should be based on the type ofrotational rheometer availa
33、ble. One criterion to select betweenthe narrow-gap and the wide-gap should be based on themaximum size of the particles in the cement tested.7.4.2.1 Narrow-Gap Concentric CylinderWith this typeof rheometer, the sample is confined between two concentriccylinders of radii R1and R2(R2R1), one of which,
34、 the rotor,is rotating at a constant rotational speed and the other isstationary. The rotation of the rotor in the presence of thesample produces a torque that is measured at the wall of theinner cylinder. The cylinder radii should be selected such thatthe shear stress is uniform across the gap. Thi
35、s condition isassumed to be satisfied if:SR1R2D.50.92 (1)where R1is the radius of the inner rotating cylinder (m) andR2is the radius of the outer stationary cylinder (m).5To prevent slip (development of a liquid layer at the wall ofthe rotating cylinder that produces an anomalously low stress),the s
36、urface of cylinders may be serrated or at least rendered5DIN 53019-1:2008, ViscometryMeasurement of viscosities and flow curvesby means of rotational viscometersPart 1: Principles and measuring geometry.C1749 17a2rough by attaching a sand paper, sand blasting, or othermethods that roughen the surfac
37、e such as serration.The nominal shear rate and stress are calculated at the innercylinder wall by the following expression: 5R231R22 R1(2)where is strain rate (s-1) and 1is rotational speed at theinner cylinder (r/s). The nominal shear stress is calculated atthe inner cylinder wall by the following
38、expression: 52R12L(3)where is shear stress (Pa), is torque (Nm), L is cylinderlength (m), and R1is the inner radius (m). These equationsassume that the slurry is homogeneous, the shear stress isuniform in the gap, the flow regime in the gap is laminar, andslip at the wall is negligible.7.4.2.2 Wide-
39、Gap Concentric CylinderThis type of rhe-ometer is similar to the narrow-gap concentric cylinder de-scribed in 7.4.2 except that there is no limit on the gap valueand the gap is larger. Computation of strain rate and stress issimplified if it is assumed that the material follows a power-lawmodel. In
40、that case, the nominal shear rate, , is calculated atthe inner cylinder wall by the following expression: 52 31n1 2 b2/n!(4)where is strain rate (s-1), 1is the rotational speed at theinner cylinder (rad/s), b is the ratio of the inner to the outerradius, and n is the power-law exponent. A procedure
41、fordetermining the value of n is presented elsewhere.3Nominalshear stress, , is calculated at the inner cylinder wall by thefollowing expression: 52R12L(5)where is shear stress (Pa), is torque per unit length (Nm),L is cylinder length (m), and R1and R2are inner and outercylinder radii (m).Some conce
42、ntric cylinder rheometers use an extreme widegap such that the radius of the outer cylinder approachesinfinity and (1-b2/n) approaches unity. This type of rheometernormally operates only at moderately low shear rates, typically0.1 s-1to 10 s-1. For a material following a power-law model,the nominal
43、shear rate is calculated at the inner cylinder wallby the following expression: 52 31n(6)where is strain rate (s-1), 1is the rotational speed of theinner cylinder (rad/s), and n is the power-law exponent.Nominal shear stress, , is calculated at the inner cylinder wallby the following expression: 52R
44、12L(7)where is shear stress (Pa), is torque (N.m), L is cylinderlength (m), and R1is inner cylinder radius (m).7.4.2.3 Parallel PlateIn this type of rheometer the sampleis held between two parallel horizontal plates, each equal andcircular cross section. The plates may be serrated to avoidslippage.
45、When one of the plates is rotating and the other isstationary, the shear rate varies from zero at the center to amaximum at the rim, and the value at the rim is: 5R 31h(8)where is strain rate (s-1), R is the plate radius (m), 1is therotational speed (rad/s), and h is the gap between the two plates(m
46、). Viscosity is given by: 53h2R41S111dln3dln1D(9)where is viscosity (Pa.s) and is the torque (N.m).7.5 GapThe gap between the shearing surfaces of therheometer should be wide enough that the sample is homoge-neous throughout or be of the same magnitude of the distancebetween aggregates in concrete (
47、typically 0.4 mm). If the gapis too narrow relative to the size of particles in the cement paste(less than 10 times the maximum particles size), the torque willbe very high or even the plate will lock and not rotate.7.6 SlippageSlippage can occur if the shearing surfacesare smooth, due to the format
48、ion of layer of water near thesurface. If slippage occurs, the torque measured is smaller thanit should be. It could be even zero. Therefore, some precautionshould be taken to avoid slippage by serration of the shearingsurfaces. It can be done either by gluing a sand paper, or bysand blasting the su
49、rfaces or by serration of the surface withgrooves or a pattern.7.7 EvaporationPrevent evaporation of water from thepaste by covering the paste with a vapor barrier or a water-saturated material.7.8 Temperature ControlControl the temperature to thenearest 2C. The temperature may be selected to reflect thetemperature at which the cement paste would be used in thefield.7.9 VerificationPeriodically follow the procedures sug-gested by the manufacturer, or use Test Method E
