ASTM C1738-11
(Practice)Standard Practice for High-Shear Mixing of Hydraulic Cement Pastes
Standard Practice for High-Shear Mixing of Hydraulic Cement Pastes
SIGNIFICANCE AND USE
This practice is useful in laboratory research on rheology of hydraulic cement systems as it has been shown to provide a paste with rheological properties similar to those obtained in a concrete from which the aggregate had been removed. Mixing of paste using C305 is not satisfactory as the paste is not thoroughly mixed, due to the absence of sand. In this practice the shear imparted to the cement paste is significantly higher than in C305 and therefore it is known as high-shear mixing.
SCOPE
1.1 This practice covers the high-shear mixing of hydraulic cement pastes.
1.2 The values stated in SI units or inch-pound units are to be regarded as the standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation:C1738–11
Standard Practice for
High-Shear Mixing of Hydraulic Cement Pastes
This standard is issued under the fixed designation C1738; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.1 mixing, high-shear, v—ofpastes,theprocessofblend-
ingdryandliquidmaterialsinacontainerusingbladesrotating
1.1 This practice covers the high-shear mixing of hydraulic
axially at speeds at or above 420 rad/s [4000 rpm].
cement pastes.
1.2 The values stated in SI units or inch-pound units are to
4. Summary of Practice
be regarded as the standard. Within the text, the inch-pound
4.1 The practice describes the mixing of hydraulic cement
units are shown in brackets. The values stated in each system
paste in a high-shear mixer with a cooling jacket or other
are not exact equivalents; therefore, each system shall be used
method to control the temperature of the paste. This procedure
independently of the other. Combining values from the two
is derived from the ANSI/API standard and the following
systems may result in nonconformance with the standard.
reports:
1.3 This standard does not purport to address all of the
(1) R. Helmuth, L.M. Hills, D.A. Whiting, S. Bhattacharja,
safety concerns, if any, associated with its use. It is the
Abnormal Concrete Performance in the Presence of Admix-
responsibility of the user of this standard to establish appro-
tures, RP333, Portland Cement Association, Skokie, Illinois,
priate safety and health practices and determine the applica-
USA, 1995, 92 pages and
bility of regulatory limitations prior to use.
(2) C. F. Ferraris, Measurement of the rheological proper-
2. Referenced Documents ties of cement paste: a New Approach, Int. RILEM Conf.
—The role of Admixtures in High Performance Concrete, ed.
2.1 ASTM Standards:
by J.G. Cabrera and R. Rivera-Villareal, Monterrey (Mexico),
C219 Terminology Relating to Hydraulic Cement
March 1999. pp. 333-342, or
C305 Practice for Mechanical Mixing of Hydraulic Cement
(3) C. Ferraris, K. Obla, R. Hill, The influence of mineral
Pastes and Mortars of Plastic Consistency
admixtures on the rheology of cement paste and concrete,
C511 Specification for Mixing Rooms, Moist Cabinets,
Cement and Concrete Research Vol. 31/2, pp. 245-255 (2001).
Moist Rooms, and Water Storage Tanks Used in the
Testing of Hydraulic Cements and Concretes
5. Significance and Use
C1005 Specification for Reference Masses and Devices for
5.1 This practice is useful in laboratory research on rheol-
Determining Mass and Volume for Use in the Physical
ogy of hydraulic cement systems as it has been shown to
Testing of Hydraulic Cements
3 provide a paste with rheological properties similar to those
2.2 Non-ASTM Standard:
obtained in a concrete from which the aggregate had been
ANSI/API Recommended Practice 10B-2 (formerly 10B)—
removed. MixingofpasteusingC305isnotsatisfactoryasthe
Recommended Practice for Testing Well Cementsi
paste is not thoroughly mixed, due to the absence of sand. In
3. Terminology this practice the shear imparted to the cement paste is signifi-
cantly higher than in C305 and therefore it is known as
3.1 Definitions—For definitions of terms used in this speci-
high-shear mixing.
fication, refer to Terminology C219.
3.2 Definitions of Terms Specific to This Standard:
6. Apparatus
6.1 Mixer—Composed of an electrical motor, a mixing
ThispracticeisunderthejurisdictionofASTMCommitteeC01onCementand
container and a tachometer with the motor speed controlled
is the direct responsibility of Subcommittee C01.22 on Workability.
automatically (rheostat adjustment of speed will not be accept-
Current edition approved April 1, 2011. Published June 2011.
able). The blades are attached to the bottom of the container
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. R. Helmuth, L.M. Hills, D.A. Whiting, S. Bhattacharja, Abnormal Concrete
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., Performance in the Presence of Admixtures, RP333, Portland Cement Association,
4th Floor, New York, NY 10036, http://www.ansi.org. Skokie, Illinois, USA, 1995, 92 pages.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1738–11
and rotate axially. The power of the motor shall be sufficient to 7.2 The cooling unit flow rate and temperature shall be
ensure that the speeds of the mixer loaded with 500.0 g [1.1 lb] adjusted so that the temperature of the cement paste, after
of cement and water shall maintain a preset rotational speed at mixing, is within the specified range (see Note 4).
420 rad/s [4000 rpm] and 1260 rad/s [12 000 rpm]. The speed
NOTE 4—Typically water temperatures of 15 6 2°C [59 6 4°F] are
shall be maintained within 5 % of the preset speeds.
required for a cement paste temperature of 21 62°C[70 6 4°F]. Higher
or lower temperature water could be used to simulate hot or cold weather
NOTE 1—A variable speed mixer capable of controlling the speed by a
,
4 6
concrete.The references provide a more detailed explanation on how to
feedbackloopwithinarangeof0rad/s[0rpm]to1360rad/s[13000rpm]
select the cooling temperature.
is recommended, however, a mixer with a minimum of preset two speeds
420 rad/s [4000 rpm] and 1260 rad/s [12 000 rpm] loaded is acceptable.
8. Materials and Proportioning
6.2 Cooling Unit—Awater bath with an outside circulating
8.1 The materials and their proportions and quantities shall
option, capable of controlling the temperature to 61°C [61°F]
conformtotherequirementscontainedintheparticularmethod
for the specified temperature range of 5-50°C [40-120°F] over
for which the paste is being prepared.
the duration of the test.
9. Procedure
6.3 Mixing Container with the Blade Assembly —A 1-L [1
qt] container, lid and blade specifically designed for use with 9.1 Place the mixing container on the mixer and if appli-
the mixer motor. The blade assembly shall be constructed in cable, connect the hoses to the cooling unit.
such a manner that the blade can be removed for weighing and 9.2 If using an external cooling unit, adjust the temperature
changing. The blade shall be weighed initially and then to the desired temperature and turn on the water supply to the
periodically,
...
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