ASTM C862-91(1997)

Standard Practice for Preparing Refractory Concrete Specimens by Casting

SCOPE
1.1 This practice covers the mixing, casting and curing of monolithic refractory concrete specimens for use in further testing. It does not apply to monolithic castable refractories intended primarily for gunning applications.
1.2 The values given in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 Various specimen sizes are required for specific test methods. Refer to these test methods to determine the size and number of specimens, which will be required from the sample.
1.4 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.

General Information

• Status: Historical
• Publication Date: 09-Feb-2001
• ICS: 81.080 - Refractories
• Technical Committee: C08 - Refractories
• Drafting Committee: C08.09 - Monolithics

Relations

• Replaced By: ASTM C862-01 - Standard Practice for Preparing Refractory Concrete Specimens by Casting
• Effective Date: 10-Feb-2001
• Referred By: ASTM C865-22 - Standard Practice for Firing Refractory Concrete Specimens
• Effective Date: 10-Feb-2001
• Referred By: ASTM C704/C704M-15(2022)e1 - Standard Test Method for Abrasion Resistance of Refractory Materials at Room Temperature
• Effective Date: 10-Feb-2001
• Referred By: ASTM C401-12(2022) - Standard Classification of Alumina and Alumina-Silicate Castable Refractories
• Effective Date: 10-Feb-2001
• Referred By: ASTM C133-97(2021) - Standard Test Methods for Cold Crushing Strength and Modulus of Rupture of Refractories
• Effective Date: 10-Feb-2001
• Referred By: ASTM C1656-13(2023) - Standard Guide for Measuring the Reactivity of Hydraulic Refractory Castables Using Exothermic Profile
• Effective Date: 10-Feb-2001
• Referred By: ASTM C1446-19 - Standard Test Method for Measuring Consistency of Self-Flowing Castable Refractories
• Effective Date: 10-Feb-2001
• Referred By: ASTM C417-21 - Standard Test Method for Thermal Conductivity of Unfired Monolithic Refractories
• Effective Date: 10-Feb-2001
• Referred By: ASTM C16-03(2018) - Standard Test Method for Load Testing Refractory Shapes at High Temperatures
• Effective Date: 10-Feb-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 862 – 91 (Reapproved 1997)
Standard Practice for
Preparing Refractory Concrete Specimens by Casting
This standard is issued under the fixed designation C 862; 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. Scope
1.1 This practice covers the mixing and casting of castable
refractory specimens using the tempering water determined in
accordance with the consistency tests in Practices C 860. It
does not apply to castable refractories intended primarily for
gun application.
1.2 The values given in inch-pound units are to be regarded
as the standard. The values given in parentheses are for
information only.
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 appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Figs. 1-7
2. Referenced Documents
2.1 ASTM Standards:
C 133 Test Methods for Cold Crushing Strength and Modu-
lus of Rupture of Refractories
C 192 Practice for Making and Curing Concrete Test Speci-
mens in the Laboratory FIG. 1 Manually-Operated Mechanical Mixer
C 860 Practices for Determining and Measuring Consis-
tency of Refractory Concretes be controlled between 70 and 80°F (20 and 27°C) and from 40
to 60 % relative humidity for preconditioning materials and
3. Significance and Use
equipment, batching, mixing, casting test specimens, stripping
3.1 This practice is used in conjunction with the proper
molds, and testing specimens. Report laboratory temperature
water content (Practices C 860) to further assure the production and relative humidity with physical test results if other than
of uniform laboratory specimens with optimum properties for
specified.
castable testing. The practice is used to standardize the mixing, 4.2 Balances, 100-lb (45-kg) capacity with sensitivity of 0.2
mold conditions, placement and curing of refractory concrete
lb (90 g); 15-lb (6.8-kg) capacity with sensitivity of 0.02 lb (9
specimens to be used for testing and evaluation under other test
g); 4.5-lb (2-kg) capacity with sensitivity of 0.1 g.
methods.
4.3 Castable Mixers—Either a manually operated (Fig. 1)
3.2 This practice, along with Practices C 860, standardizes
or an electrically operated mechanical mixer may be used for
laboratory conditions for producing refractory concrete speci-
preparing castable batches for casting specimens. A 2-ft (56.6-
3 3 3
mens to minimize laboratory-to-laboratory variation and does
dm ) mixing bowl or a 2 ⁄2-ft (70.8-dm ) concrete mixer has
not attempt to duplicate the conditions of field installations.
sufficient capacity to mix about 1 ft of refractory castable. The
smallest batches required for casting 1-in. (25-mm) square bars
4. Apparatus and Conditions
3 3
can be mixed in 0.10-ft (2.83-dm ) bowl available with bench
4.1 Laboratory Conditions—The laboratory ambient should
mixers. Size mixing bowl to contain from 50 to 75 % volume
loading with the dry batch.
1 NOTE 1—Castable water requirement variation becomes more signifi-
This practice is under the jurisdiction of ASTM Committee C-8 on Refractories,
cant as dry volume loadings drop below 50 % because the water required
and is the direct responsibility of Subcommittee C08.09 on Monolithic Refractories.
Current edition approved Dec. 15, 1991. Published February 1992. Originally
published as C 862 – 77. Last previous edition C 862 – 87.
2 4
Annual Book of ASTM Standards, Vol 15.01. Suitable mixers having various capacities are available from the Hobart
Annual Book of ASTM Standards, Vol 04.02. Manufacturing Co., Troy, OH.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
C 862
4.8 Mold Lubricant—Either paraffin or silicone-based oils
can be used as a release or parting agent for coating molds.
4.9 Strike-Off Bar, 20-in. (510-mm) length of steel bar
1 3
stock, 1 ⁄2 by ⁄16 in. (38 by 5 mm).
4.10 Thermometer, dial-type, metal, with a range from 0 to
180°F (−18 to 80°C).
4.11 Timer, signal-type, for periods up to 5 min.
4.12 Trowels, 6 in. pointing and 2 by 6 in. (51 by 152 mm)
square, and a 10-in. (254-mm) stainless-steel spatula.
4.13 Oven, for curing and drying, preferably forced draft
rather than natural convection, with a capacity to hold ten 9-in.
(230-mm) straight brick.
5. Sampling
5.1 Sufficiently dry castable should be batched to obtain at
least a 10 % excess of material required to fill the gang molds
and to eliminate use of both tailings and scrapings.
5.2 At the time of use, the dry sample should be between 70
and 80°F (20 and 27°C). Measure the temperature by inserting
the full length of the dial-thermometer stem into the material
until the reading is constant. Record and report with physical
test results.
NOTE 2—It is recommended that in referee tests involving more than
one laboratory, the temperature of the dry refractory concrete mix and
mixing water be the same, within the specified range, in all laboratories.
5.3 The contents of the container should be thoroughly
mixed dry prior to water addition. When less than a full bag is
required, reduce the contents of the sample container (Note 3)
with a sample splitter to obtain a quartered sample of the
desired batch size. Take precautions to prevent segregation.
FIG. 2 Five-Brick Gang Mold for Castable Refractories
NOTE 3—When the castable mix consists of more than one bag or
to wet the bowl surfaces changes more rapidly with decreasing volume container, the contents should be combined and mixed thoroughly before
loadings. being quartered.
4.4 Gang Molds, metal, two or more sets, as shown in Fig.
6. Molding Test Specimens
2 and Fig. 3, for casting specimens to the size required for
6.1 Prior to filling each mold, use the calipers to obtain a
specific physical property testing (see Note 9). The front plate
measurement of the internal length to the nearest 0.01 in. (0.3
of the mold illustrated is held in place by quick-release clamps
mm). Record this value to provide the basis for determining
(50-lbf (222-N) pull exerted by each clamp) that permit
linear change of cured, dried, and fired specimens. An optional
emptying the mold by releasing the clamps and tapping the left
procedure for establishing an initial reference point is de-
end of the front plate, thereby parting all of the separator plates
5 scribed in 6.3.
and loosening the cast-test specimens.
6.2 Immediately after mixing, start the timer and begin
4.4.1 As an alternative design for 1 in. (25-mm) square bars,
filling the molds. Use a scoop for cutting into the batch to get
individual molds may be constructed out of 16-gage (1.588-
a good section and half-fill each mold cavity. Consolidate the
mm) stainless-steel sheet and ganged in groups of five with a
material in the molds by spading at close intervals with a
large rubber band on a glass base-plate.
square trowel or spatula held vertically, and with the blade
4.5 Calipers, suitable for measuring internal longitudinal
turned to form an angle of 45° with the side of the mold. Spade
mold dimensions and subsequent specimen length size to the
along the length and then reverse the 45° angle for the next
nearest 0.01 in. (0.3 mm).
pass along the mold. Fill the molds with an excess of the mix
4.6 Indentation Marker, as described in Fig. 5, and shown in
and repeat the trowel-spading. Use the strike-off bar with a
Fig. 6 and Fig. 7, for use in establishing initial linear dimension
sawing motion to remove the excess mix, then smooth the
and subsequent linear changes.
exposed surface with a minimum amount of troweling. Com-
4.7 Steel Rule, capable of measuring dimensional changes
plete the operation of filling the molds within 5 min or at the
of an 8-in. (203-mm) span to the nearest 0.01 in. (0.3 mm).
rate of 1 min per test specimen. Mechanical vibration should
not be used.
Drawings of the manual mixer and a list of materials and notes on construction
NOTE 4—The cited procedure is applicable when filling deep molds,
of the 9-in. (230-mm) straight-brick gang molds are available at a nominal charge
that is, brick molds as shown in Fig. 2 or larger. Hand placement of the
from the Refractories Research Center, Ohio State University, 2041 N. College
Road, Columbus, OH 43210. castable can be used to fill and consolidate the material in shallow molds
C 862
Metric Equivalents
1 1 5 3 1 5 3 1 9 5 11
in. ⁄32 ⁄8 ⁄32 ⁄16 ⁄4 ⁄16 ⁄8 ⁄2 ⁄16 ⁄8 ⁄16
mm 0.8 3 4 5 6 8 10 13 14 16 17
7 3 1 1 5 3 1 3
in. ⁄8 1 ⁄16 1 ⁄2 2 ⁄2 2 ⁄8 3 ⁄16 4 4 ⁄2 9 14 ⁄4
mm 22 30 38 65 67 81 102 114 230 375
1 1 1
NOTE 1—Sizes other than 9-in. straights commonly used for physical testing are: 2 ⁄2 by 4 ⁄2 by 4 ⁄2 in. (65 by 114 by 114 mm); 2 by 2 by 7 or 9 in.
1 1 1
(51 by 51 by 178 or 230 mm); 1 ⁄2 by 1 ⁄2 by 4 ⁄2 in. (38 by 38 by 114 mm); or 1 by 1 by 6 or 7 in. (25 by 25 by 152 or 178 mm). Dimensions are in
inches.
FIG. 3 Detail Drawing for Gang Mold
NOTE 1—Dimensions are in inches.
FIG. 4 Mixing Box
(normally 2 in. (50 mm) deep or less). Appropriate spading with the
surface as the specimen begins to set (generally from 5 to 20
spatula should be used with finger tamping to ensure consolidation of the
min). Use the calibrated marking device with knife edges at a
material into the mold corners.
known separation, for
...