ASTM C133-97(2008)
(Test Method)Standard Test Methods for Cold Crushing Strength and Modulus of Rupture of Refractories
Standard Test Methods for Cold Crushing Strength and Modulus of Rupture of Refractories
SIGNIFICANCE AND USE
The cold strength of a refractory material is an indication of its suitability for use in refractory construction. (It is not a measure of performance at elevated temperatures.)
These test methods are for determining the room temperature flexural strength in 3-point bending (cold modulus of rupture) or compressive strength (cold crushing strength), or both, for all refractory products.
Considerable care must be used to compare the results of different determinations of the cold crushing strength or modulus of rupture. The specimen size and shape, the nature of the specimen faces (that is, as-formed, sawed, or ground), the orientation of those faces during testing, the loading geometry, and the rate of load application, may all significantly affect the numerical results obtained. Comparisons of the results between different determinations should not be made if one or more of these parameters differ between the two determinations.
The relative ratio of the largest grain size to the smallest specimen dimension may significantly affect the numerical results. For example, smaller, cut specimens containing large grains may present different results than the bricks from which they were cut. Under no circumstances should 6- by 1- by 1-in. (152- by 25- by 25-mm) specimens be prepared and tested for materials containing grains with a maximum grain dimension exceeding 0.25 in. (6.4 mm).
This test method is useful for research and development, engineering application and design, manufacturing process control, and for developing purchasing specifications.
SCOPE
1.1 These test methods cover the determination of the cold crushing strength and the modulus of rupture (MOR) of dried or fired refractory shapes of all types.
1.2 The test methods appear in the following sections:
Test Method Sections Cold Crushing Strength 4 to 9 Modulus of Rupture 10 to 15
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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.
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Standards Content (Sample)
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Designation:C 133–97 (Reapproved 2008)
Standard Test Methods for
Cold Crushing Strength and Modulus of Rupture of
Refractories
This standard is issued under the fixed designation C 133; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 3. Significance and Use
1.1 These test methods cover the determination of the cold 3.1 The cold strength of a refractory material is an indica-
crushing strength and the modulus of rupture (MOR) of dried tionofitssuitabilityforuseinrefractoryconstruction.(Itisnot
or fired refractory shapes of all types. a measure of performance at elevated temperatures.)
1.2 The test methods appear in the following sections: 3.2 These test methods are for determining the room tem-
perature flexural strength in 3-point bending (cold modulus of
Test Method Sections
rupture) or compressive strength (cold crushing strength), or
Cold Crushing Strength 4 to 9
both, for all refractory products.
Modulus of Rupture 10 to 15
3.3 Considerable care must be used to compare the results
1.3 The values stated in inch-pound units are to be regarded
of different determinations of the cold crushing strength or
as standard. The values given in parentheses are mathematical
modulus of rupture.The specimen size and shape, the nature of
conversions to SI units that are provided for information only
the specimen faces (that is, as-formed, sawed, or ground), the
and are not considered standard.
orientation of those faces during testing, the loading geometry,
1.4 This standard does not purport to address all of the
and the rate of load application, may all significantly affect the
safety concerns, if any, associated with its use. It is the
numericalresultsobtained.Comparisonsoftheresultsbetween
responsibility of the user of this standard to establish appro-
different determinations should not be made if one or more of
priate safety and health practices and determine the applica-
these parameters differ between the two determinations.
bility of regulatory limitations prior to use.
3.4 The relative ratio of the largest grain size to the smallest
specimen dimension may significantly affect the numerical
2. Referenced Documents
results. For example, smaller, cut specimens containing large
2.1 ASTM Standards:
grains may present different results than the bricks from which
C 862 Practice for Preparing Refractory Concrete Speci-
they were cut. Under no circumstances should 6- by 1- by 1-in.
mens by Casting
(152- by 25- by 25-mm) specimens be prepared and tested for
C 1054 Practice for Pressing and Drying Refractory Plastic
materials containing grains with a maximum grain dimension
and Ramming Mix Specimens
exceeding 0.25 in. (6.4 mm).
E4 Practices for Force Verification of Testing Machines
3.5 Thistestmethodisusefulforresearchanddevelopment,
engineering application and design, manufacturing process
control, and for developing purchasing specifications.
These test methods are under the jurisdiction of ASTM Committee C08 on
COLD CRUSHING STRENGTH
Refractories and are the direct responsibility of Subcommittee C08.01 on Strength.
Current edition approved Aug. 1, 2008. Published September 2008. Originally
4. Apparatus
approved in 1937. Last previous edition approved in 2003 as C 133 – 97 (2003).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.1 Testing Machine—Any form of standard mechanical or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
hydraulic compression testing machine conforming to the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. requirements of PracticesE4 may be used.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 133–97 (2008)
NOTE 1—For low-strength materials (such as insulating bricks or
220 to 230°F (105 to 110°C) for 18 h (overnight). Upon
castables), a sensitivity of 20 lbf (67 kN) or less is required. The use of a
removal from the oven, allow the sample to cool naturally until
hydraulic testing machine is also preferred over the mechanical type for
cool to the touch. Complete testing within2hof removal from
these materials.
the drying oven. (See Practices C 862 and C 1054.)
4.2 Spherical Bearing Block—The plane surface of the
6. Procedure
spherical bearing block (see Fig. 1) shall have an area which is
equal to or greater than the cross section of the test specimen. 6.1 At least five specimens from an equivalent number of
refractory shapes compose a sample.
5. Test Specimens
NOTE 2—For relatively weak specimens like insulating castables or
5.1 Brick and Shapes (bulk density greater than 100 lb/ft
insulating firebricks, a minimum sample size of ten specimens is pre-
(1.60 g/cm ))—The test specimens shall be 2-in. (51-mm)
ferred.
cubes or cylinders, 2 in. (51 mm) in diameter by 2 in. (51 mm)
6.2 Brick and Shapes—Place a cellulose fiber wall board
high. The height should be parallel to the original direction of
(for example, Masonite ) 0.25 in. (6.4 mm) in thickness and
pressing of the brick or shape. In the case of special shapes,
extending 0.5 in. (12.7 mm) or more beyond the edges of the
only one specimen shall be cut from a single shape and as
loaded faces of the specimen. Apply the load parallel to the
many of the original surfaces as possible shall be preserved. In
direction in which the brick was originally pressed.
preparing specimens from irregular or large refractory shapes,
6.3 RegularandHighStrengthCastables—Placeacellulose
any method involving the use of abrasives, such as a high-
fiber wall board 0.25 in. (6.4 mm) in thickness and extending
speed abrasion wheel, core drill, or rubbing bed, that will
0.5 in. (12.7 mm) or more beyond the edges of the loaded faces
produce a specimen with approximately plane and parallel
of the specimen. Apply the load on the 2- by 2-in. (51- by
sides without weakening the structure of the specimen may be
51-mm) or 2-in. (51-mm) diameter face and perpendicular to
used.
the depth of the specimen as originally cast or gunned.
5.2 Insulating Brick or Shapes (typical bulk density of 100
6.4 Insulating Brick or Shapes—Apply the load directly to
3 3
lb/ft (1.60 g/cm ), or greater than 45 % total porosity, or
1 1
the 4 ⁄2-by4 ⁄2-in. (114- by 114-mm) surface of the test
1 1 1
both)—The test specimens shall be 4 ⁄2 by 4 ⁄2 by 2 ⁄2 or 3 in.
specimen.
(114by114by64or76mm),eachtakenfromadifferentbrick.
6.5 Insulating Castables (typical bulk density of 100 lb/ft
It is permissible to prepare these specimens from the half-brick
(1.60 g/cm ), or greater than 45 % total porosity, or both)—
resultingfromthemodulusofrupturetest(seeSections10-15).
Apply the load directly to the 2- by 2-in. (51- by 51-mm) face
The selected compression test section shall be free of cracks,
and perpendicular to the depth of the specimen as originally
chipped surfaces, and other obvious defects. The test surfaces
cast or gunned.
shall be approximately parallel planes.
6.6 Use the bearing block on top of the test specimen, and
5.3 Castable Refractories—The test specimens shall be 2-
position it so that the center of the sphere is in alignment with
by 2- by 2-in. (51- by 51- by 51-mm) cubes or cylinders 2 in.
the vertical axis of the specimen (see Fig. 1). Keep the
(51 mm) in diameter by 2 in. (51 mm) high, prepared by
spherical bearing block thoroughly lubricated to ensure accu-
casting or gunning. It is permissible to prepare one specimen
rate adjustment which may be made by hand under a small
from each 9- by 2- by 2-in. (230- by 51- by 51-mm) bar after
initial load for each specimen.
the modulus of rupture test (see Sections 10-15). The selected
NOTE 3—The spherical bearing block may not be necessary on test
compression test section shall be free of cracks, chipped
machines having mechanical linkages which ensure that the stress applied
surfaces, and other obvious defects. The loaded surfaces shall
is colinear with the axis of the specimen.
be approximately parallel planes.All samples must be dried at
6.7 For dense refractories with sufficient strength to require
greater than about 3 min per test, initial loading to one-half of
the anticipated failure load may be accomplished at any
convenient rate exceeding the specified rate. Subsequently,
each specimen shall be crushed with a compressive load
appliedatthestandardratesspecifiedinTable1.Theratesshall
not vary by more than 610 % of the specified rate for the type
of refractory being tested.
6.8 When using a mechanical testing machine, keep the
balance beam in a constantly floating position.
6.9 Specimens are loaded, as specified, to failure. Failure is
defined as the collapse of the specimen (failure to support the
load), or the reduction of the specimen height to 90 % of its
original value. The maximum applied load is recorded.
7. Calculation
7.1 Calculate the cold crushing strength using Eq 1:
FIG. 1 Recommended Design for Crushing Test Assembly,
Including Bearing Block Masonite has been found satisfactory for this purpose.
C 133–97 (2008)
TABLE 1 Standard Loading Rates for Cold Crushing Strength
Stress Rate,
2 A
Loaded Cross Loaded Area, in. Loading Rate, Strain Rate,
Refractory Type Size, in. (mm) lbf/in. /min
Section, in. (mm) mm ) lbf/min (kN/min) in./min (mm/min)
(MPa/min)
Refractory Brick and Shapes
3 3 B B B
Density >100 lb/ft (>1.60 gm/cm ), or 2 3 2 3 2 2 3 2 4 1750 7000 0.05
<45 % true porosity, or both (51 3 51 3 51) (51 3 51) (2601) (12) (31.2) (1.3)
B B B
(Includes regular or high strength castables 2 diameter 3 2 2, diameter 3.14 1750 5500 0.05
and fired plastic or rammed refractories) (51 diameter 3 51) (51, diameter) (2027) (12) (24.3) (1.3)
Insulating Refractories
3 3 C,D
Density <100 lb/ft (<1.60 gm/cm ), or 4.5 3 4.5 3 2.5 4.5 3 4.5 20.25 435 8809 0.05
>45 % true porosity, or both (114 3 114 3 64) (114 3 114) (13 064) (3) (39) (1.3)
C,D
(Includes dried, unfired plastic or rammed 4.5 3 4.5 3 3 4.5 3 4.5 20.25 435 8809 0.05
refractories) (114 3 114 3 76) (114 3 114) (13 064) (3) (39) (1.3)
D,E
2 3 2 3 2 2 3 2 4 435 1740 0.05
(51 3 51 3 51) (51 3 51) (2601) (3) (7.80) (1.3)
E
2 diameter 3 2 2, diameter 3.14 435 1367 0.05
(51 diameter 3 51) (51, diameter) (2027) (3) (6.08) (1.3)
A
Where possible, loading at a constant stress rate is preferable to constant strain rate loading.
B
For dense refractory brick and shapes requiring more than a 3-min test duration, specimens may be loaded to one half of the anticipated fracture strength at any
convenient rate exceeding that specified.
C
These sizes are preferred for insulating firebricks.
D
These pieces may be cut from broken halves of MOR specimens.
E
These sizes are preferred for insulating castables.
S 5 W/A (1)
MODULUS OF RUPTURE
10. Apparatus
where:
10.1 TestingMachine—Anyformofstandardmechanicalor
hydraulic compression testing machine conforming to the
S = cold crushing strength, lbf/in. (MPa),
requirements of PracticesE4 may be used.
W = total maximum load indicated by the testing machine,
lbf (N), and
NOTE 4—Properly calibrated portable apparatus may be used.
A = average of the areas of the top and bottom of the
10.2 Bearing Surfaces, that shall have a radius of curvature
specimen perpendicular to the line of application of
5 1
2 2 of ⁄8 in. (16 mm) or be cylindrical pieces 1 ⁄4-in. (32-mm) in
the load, in. (mm ).
diameter. For 6- by 1- by 1-in. (152- by 25- by 25-mm)
specimens, the radius of curvature shall be ⁄16 in. (5 mm) or
8. Report
cylindrical pieces ⁄8 in. (10 mm) in diameter.All such bearing
8.1 Report the following:
surfaces shall be straight and of a length at least equal to the
8.1.1 Designation of the materials tested (that is, manufac-
width of the test specimen. The supporting members for the
turer, brand, description, lot number, etc.);
lower bearing surfaces shall be constructed so as to provide a
8.1.2 Specimen configuration, including size, shape, loca-
means for the alignment of the bearing surfaces with the under
tion in the original brick or shape, the character of the faces
surface of the test specimen because the test brick may have a
(that is, cut, drilled, as-pressed, as-cast, etc.), and the specimen
longitudinal twist. Apparatus of the design shown in Fig. 2 is
orientation during testing;
recommended, although other types may be used, provided
8.1.3 Pretreatment, if any, given to the test pieces (for
they conform to these requirements. A satisfactory alternative
example, curing, firing, coking, etc.);
design is shown in Fig. 3.
8.1.4 Number of specimens in a sample;
8.1.5 Individual specimen dimensions, the maximum ap-
11. Test Specimens
plied load, and the calculated cold crushing strength for each 3
11.1 Brick and Shapes (bulk density greater than 100 lb/ft
specimen (see 7.1); 3
(1.60 g/cm )—The preferred test specimens shall be standard
8.1.6 Mean cold crushing strength and standard deviation
1 1
9- by 4 ⁄2-by2 ⁄2- or 3-in. (228- by 114- by 64- or 76-mm)
for each sample.
bricks, or specimens of equivalent size ground or cut from
refractory shapes. In the case of special shapes, only one
9. Precision and Bias
specimen shall be cut from a single shape. As many original
9.1 Precision—Theprecisionofthistestmethodiscurrently
surfaces as possible shall be preserved. Where brick sizes are
being investigated. impossible or impracticable, alternative specimen sizes of 9 by
9.2 Bias—No justifiable statement can be made on the bias 2 by 2 in. (228 by 51 by 51 mm) or 6 by 1 by 1 in. (152 by 25
of the test method for measuring the cold crushing strength of by 25 mm) may be prepared. In preparing specimens from
refractories, because the value of cold crushing strength can be irregular or larger shapes, any method involving the use of
defined only in terms of a test method. abrasives, such as a high-speed abrasion wheel or rubbing bed,
C 133–97 (2008)
NOTE—The dimensions appearing in Fig. 2 are in inches. See table below for metric equivalents.
in. mm in. mm
3 1
⁄16 51 ⁄2 38
⁄4 62 51
⁄8 10 3 76
⁄2 13 4 102
5 1
⁄8 16 4 ⁄2 114
⁄4 19 5 127
1 25 7 178
1 ⁄4 32 12 305
FIG. 2 Recommended Design of Bearing Cylinders for Modulus of Rupture Test
12. Procedure
12.1 At least five specimens from an equivalent number of
refractory shapes compose a sample.
NOTE 5—For relatively weak specimens like insulating refractories, a
minimum sampl
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