ASTM C305-12
(Practice)Standard Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
Standard Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
SIGNIFICANCE AND USE
This practice is intended for use in the mechanical mixing of pastes and mortars for the testing of hydraulic cements.
SCOPE
1.1 This practice covers the mechanical mixing of hydraulic cement pastes and mortars of plastic consistency.
1.2 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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Designation: C305 − 12 AmericanAssociation State
Highway and Transportation Officials Standard
AASHTO No.: T162
Standard Practice for
Mechanical Mixing of Hydraulic Cement Pastes and Mortars
1
of Plastic Consistency
This standard is issued under the fixed designation C305; 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
1. Scope* 124 W ( ⁄6 hp). The mixer shall be equipped with either an
adjustment screw which is an integral part of the mixer or a
1.1 This practice covers the mechanical mixing of hydraulic
clearance adjustment bracket such as the one shown in Fig. 1
cement pastes and mortars of plastic consistency.
(Note 1) to provide clearance between the lower end of the
1.2 This standard does not purport to address all of the
paddle and the bottom of the bowl that is not greater than 2.5
safety concerns, if any, associated with its use. It is the
mm but not less than 0.8 mm (Note 2) when the bowl is in the
responsibility of the user of this standard to establish appro-
mixing position.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
NOTE 1—When the bracket is in the proper position beneath the motor
housing, the lugs are to the front and facing upward and the heads of the
2. Referenced Documents adjustment screws are to the rear and facing downward in the path of the
sliding frame that holds the bowl. It is intended that the bracket be
2
2.1 ASTM Standards:
fastened at the front housing connection by inserting replacement screws
C511 Specification for Mixing Rooms, Moist Cabinets,
onanappropriatesizeupwardthroughtheopeningineachlugandintothe
existing threaded holes in the bottom of the motor housing. The original
Moist Rooms, and Water Storage Tanks Used in the
stops for the sliding frame are to be filed down if they prevent the frame
Testing of Hydraulic Cements and Concretes
from coming in contact with the adjustment screws.
C778 Specification for Sand
NOTE 2—This is the approximate diameter of a grain of 20-30 sand as
described in Specification C778.
3. Significance and Use
4.2 Paddle—The paddle shall be readily removable, made
3.1 This practice is intended for use in the mechanical
of stainless steel, and shall conform to the basic design shown
mixing of pastes and mortars for the testing of hydraulic
in Fig. 2.The dimensions of the paddle shall be such that when
cements.
in the mixing position the paddle outline conforms to the
4. Apparatus
contour of the bowl used with the mixer, and the clearance
betweencorrespondingpointsontheedgeofthepaddleandthe
4.1 Mixer—The mixer shall be an electrically driven me-
side of the bowl in the position of closest approach shall be
chanical mixer of the epicyclic type, which imparts both a
approximately 4.0 mm but not less than 0.8 mm.
planetary and a revolving motion to the mixer paddle. The
mixer shall have a minimum of two speeds, controlled by
4.3 Mixing Bowl—The removable mixing bowl shall have a
definite mechanical means. (Rheostat adjustment of speed will
nominal capacity of 4.73 L, shall be of the general shape and
not be acceptable.) The first, or slow speed shall revolve the
comply with the limiting dimensions shown in Fig. 3, and shall
paddle at a rate of 140 6 5 r/min, with a planetary motion of
be made of stainless steel. The bowl shall be so equipped that
approximately 62 r/min. The second speed shall revolve the
it will be positively held in the mixing apparatus in a fixed
paddle at a rate of 285 6 10 r/min, with a planetary motion of
position during the mixing procedure. Provide an enclosure
approximately 125 r/min. The electric motor shall be at least
around the mixing bowl or a lid to minimize evaporation of
waterduringperiodsofrestofthemixture.Theenclosureorlid
shall be made of non-absorbing material that is resistant to
1
This practice is under the jurisdiction ofASTM Committee C01 on Cement and
is the direct responsibility of Subcommittee C01.22 on Workability. deterioration from the alkaline environment of cement pastes
Current edition approved July 1, 2012. Published July 2012. Originally approved
and mortars.
in 1953. Last previous edition approved in 2011 as C305 - 11. DOI: 10.1520/C0305-
12.
4.4 Scraper—The scraper shall consist of a semirigid rubber
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
blade attached to a handle about 150 mm long. The blade shall
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
be about 75 mm long, 50 mm wide, and tapered to a thin edge
Standards volume information, refer to the standard’s Documen
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
American Association State
Designation:C305–11 Designation:C305–12 Highway and Transportation Officials Standard
AASHTO No.: T162
Standard Practice for
Mechanical Mixing of Hydraulic Cement Pastes and Mortars
1
of Plastic Consistency
This standard is issued under the fixed designation C305; 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*
1.1 This practice covers the mechanical mixing of hydraulic cement pastes and mortars of plastic consistency.
1.2 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.
2. Referenced Documents
2
2.1 ASTM Standards:
C511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of
Hydraulic Cements and Concretes
C778 Specification for Sand
3. Significance and Use
3.1 This practice is intended for use in the mechanical mixing of pastes and mortars for the testing of hydraulic cements.
4. Apparatus
4.1 Mixer—The mixer shall be an electrically driven mechanical mixer of the epicyclic type, which imparts both a planetary
and a revolving motion to the mixer paddle. The mixer shall have a minimum of two speeds, controlled by definite mechanical
means. (Rheostat adjustment of speed will not be acceptable.) The first, or slow speed shall revolve the paddle at a rate of 140 6
5 r/min, with a planetary motion of approximately 62 r/min.The second speed shall revolve the paddle at a rate of 285 6 10 r/min,
1
withaplanetarymotionofapproximately125r/min.Theelectricmotorshallbeatleast124W( ⁄6hp).Themixershallbeequipped
with either an adjustment screw which is an integral part of the mixer or a clearance adjustment bracket such as the one shown
in Fig. 1 (Note 1) to provide clearance between the lower end of the paddle and the bottom of the bowl that is not greater than
2.5 mm but not less than 0.8 mm (Note 2) when the bowl is in the mixing position.
NOTE 1—When the bracket is in the proper position beneath the motor housing, the lugs are to the front and facing upward and the heads of the
adjustment screws are to the rear and facing downward in the path of the sliding frame that holds the bowl. It is intended that the bracket be fastened
at the front housing connection by inserting replacement screws on an appropriate size upward through the opening in each lug and into the existing
threaded holes in the bottom of the motor housing. The original stops for the sliding frame are to be filed down if they prevent the frame from coming
in contact with the adjustment screws.
NOTE 2—This is the approximate diameter of a grain of 20-30 sand as described in Specification C778.
4.2 Paddle—The paddle shall be readily removable, made of stainless steel, and shall conform to the basic design shown in Fig.
2. The dimensions of the paddle shall be such that when in the mixing position the paddle outline conforms to the contour of the
bowl used with the mixer, and the clearance between corresponding points on the edge of the paddle and the side of the bowl in
the position of closest approach shall be approximately 4.0 mm but not less than 0.8 mm.
4.3 Mixing Bowl—The removable mixing bowl shall have a nominal capacity of 4.73 L, shall be of the general shape and
comply with the limiting dimensions shown in Fig. 3, and shall be made of stainless steel. The bowl shall be so equipped that it
will be positively held in the mixing apparatus in a fixed position during the mixing procedure.There shall be provided a lid, made
of a nonabsorbing material not attacked by the cement. , and shall be made of stainless steel. The bowl shall be so equipped that
it will be positively held in the mixing apparatus in a fixed position during the mixing procedure. Provide an enclosure around the
1
This practice is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.22 on Workability .
Current edition approvedApril 1, 2011. Published May 2011. Originally approved in 1953. Last previous edition approved in 2006 as C305–06. DOI: 10.1520/C0305-11.
Current edition approved July 1, 2012. Published July 2012. Originally approv
...
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