ASTM C305-99e1
(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
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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American Association State
e1
Designation:C305–99 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 C 305; 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 (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Footnote 3 was editorially updated January 2002.
1. Scope (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
1.1 This practice covers the mechanical mixing of hydraulic
mm but not less than 0.8 mm (Note 2) when the bowl is in the
cement pastes and mortars of plastic consistency.
mixing position.
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
NOTE 1—When the bracket is in the proper position beneath the motor
responsibility of the user of this standard to establish appro-
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
priate safety and health practices and determine the applica-
sliding frame that holds the bowl. It is intended that the bracket be
bility of regulatory limitations prior to use.
fastened at the front housing connection by inserting replacement screws
onanappropriatesizeupwardthroughtheopeningineachlugandintothe
2. Referenced Documents
existing threaded holes in the bottom of the motor housing. The original
2.1 ASTM Standards:
stops for the sliding frame are to be filed down if they prevent the frame
2
C 778 Specification for Standard Sand
from coming in contact with the adjustment screws.
NOTE 2—This is the approximate diameter of a grain of 20-30 sand as
3. Significance and Use
described in Specification C 778.
3.1 This practice is intended for use in the mechanical
4.2 Paddle—The paddle shall be readily removable, made
mixing of pastes and mortars for the testing of hydraulic
of stainless steel, and shall conform to the basic design shown
2
cements.
in Fig. 2. The dimensions of the paddle shall be such that
when in the mixing position the paddle outline conforms to the
4. Apparatus
contour of the bowl used with the mixer, and the clearance
4.1 Mixer—The mixer shall be an electrically driven me-
betweencorrespondingpointsontheedgeofthepaddleandthe
chanical mixer of the epicyclic type, which imparts both a
side of the bowl in the position of closest approach shall be
planetary and a revolving motion to the mixer paddle. The
approximately 4.0 mm but not less than 0.8 mm.
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 3
comply with the limiting dimensions shown in Fig. 3, and
paddle at a rate of 140 6 5 r/min, with a planetary motion of
shall be made of stainless steel. The bowl shall be so equipped
approximately 62 r/min. The second speed shall revolve the
that 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. There shall be provided
approximately 125 r/min. The electric motor shall be at least
a lid, made of a nonabsorbing material not attacked by the
3
1
124W( ⁄6hp). The mixer shall be equipped with either an
cement.
adjustment screw which is an integral part of the mixer or a
4.4 Scraper—Thescrapershallconsistofasemirigidrubber
clearance adjustment bracket such as the one shown in Fig. 1
blade attached to a handle about 150 mm long. The blade shall
be about 75 mm long, 50 mm wide, and tapered to a thin edge
about 2 mm thick.
1
This practice is under the jurisdiction ofASTM Committee C01 on Cement and
is the direct responsibility of Subcommittee C01.22 on Workability.
NOTE 3—Akitchen tool known as a plate and bowl scraper conforms to
Current edition approved June 10, 1999. Published June 1999. Originally
these requirements.
published as C 305 – 53 T. Last previous edition C 305 – 94.
2
Annual Book of ASTM Standards, Vol 4.01.
4.5 Supplementary Apparatus—The balances, weights,
3
The Model N-50AMixer, manufactured by the Hobart Corporation, Troy, OH,
glass graduates, and any other supplementary apparatus used in
is considered to conform to these requirements. This mixer incorporates a stainless
measuring and preparing the mortar materials prior to mixing
steel “B” flat beat
...
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