ASTM C198-91(2001)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 198 – 91 (Reapproved 2001)
Standard Test Method for
Cold Bonding Strength of Refractory Mortar
This standard is issued under the fixed designation C 198; 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 patible for use at high operating temperatures. The user must
determine this compatibility. Only brick and mortar combina-
1.1 This test method covers the determination of the bond-
tions known or intended to be compatible for a particular use
ing strength of air-setting refractory mortar by determining the
should be tested.
flexural strength (modulus of rupture) at room temperature of
3.3 Properties of the brick, including its strength, apparent
oven-dried brick-mortar joints.
porosity, and pore size distribution, can affect the measurement
1.2 The values stated in inch-pound units are to be regarded
of both the bonding strength of the brick-mortar composite and
as the standard. The values stated in SI units are for informa-
the intrinsic strength of the mortar. The average modulus of
tion only.
rupture of the test brick, as determined by Test Method C 133,
1.3 This standard does not purport to address all of the
should exceed that expected for the mortar being tested. The
safety concerns, if any, associated with its use. It is the
testing of specific brands or lots of brick and mortar is
responsibility of the user of this standard to establish appro-
preferred.
priate safety and health practices and determine the applica-
3.4 Three modes of failure are available: the break may
bility of regulatory limitations prior to use.
occur within the brick itself, at the brick-mortar interface, or
2. Referenced Documents within the mortar itself. The latter provides a practical mea-
surement of the strength of the mortar itself and is the
2.1 ASTM Standards:
predominant mode of failure with the four-point flexure test
C 78 Test Method for Flexural Strength of Concrete (Using
described. The three-point flexure test measures the failure
Simple Beam With Third-Point Loading)
strength of the brick-mortar composite. Failure within the brick
C 133 Test Methods for Cold Crushing Strength and Modu-
itself suggests that either the particular brick contained a
lus of Rupture of Refractories
serious flaw, or that the mortar joint strength is of the same
C 651 Test Method for Flexural Strength of Manufactured
magnitude or greater than that of the refractory brick. The
Carbon and Graphite Articles Using Four-Point Loading at
mode of failure should always be reported in the final report.
Room Temperature
3.5 A ruggedness test for this test method performed in
E 4 Practices for Force Verification of Testing Machines
1985 found the following variables to be rugged: specimen size
3. Significance and Use
(2.5 to 3.0 in.), mortared surface (cut versus uncut), joint
1 1
thickness ( ⁄16 to ⁄8 in.), pulling of rods (fast versus slow), the
3.1 The data developed by this test method show the
loading rate (500 to 1000 lbf/min), the method of load
bonding strength and intrinsic strength of different qualities of
application (3- versus 4-point), and the operator.
air-setting mortar. The procedures described in this test method
3.6 The cold bonding strengths of refractory mortars ob-
measure the bonding strength and intrinsic strength of air-
tained by this test method are suitable for use in research and
setting mortars when used with specific brands or lots of
development, quality control, and for establishing and evalu-
refractory brick.
ating compliance with specifications between producers and
3.2 Note that it is possible to obtain results with these
consumers.
methods for brick and mortar combinations which are incom-
4. Apparatus
1 1
This test method is under the jurisdiction of ASTM Committee C08 on
4.1 Brick—At least five 9 by 4 ⁄4 by 2 ⁄2-in. (230 by 114 by
Refractories and is the direct responsibility of Subcommittee C08.09 on Monolithic
65-mm) straight brick having plane surfaces and true rectan-
Refractories.
gular shape and an average modulus of rupture higher than that
Current edition approved Jan. 25, 1991. Published August 1991. Originally
e1
published as C 198 – 45 T. Last previous edition C 198 – 91 (1996) .
Annual Book of ASTM Standards, Vol 04.02.
Annual Book of ASTM Standards, Vol 15.01.
4 6
Annual Book of ASTM Standards, Vol 05.04. Supporting data on ruggedness testing is available from ASTM. Request
Annual Book of ASTM Standards, Vol 03.01. RR:C-8-1008.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
C 198 – 91 (2001)
expected from the mortar under test, when determined in 5.2 Dry Mortars—The sample of mortar submitted shall be
accordance with Test Methods C 133, compose a sample.
a prepared test sample of 10 lb (4.5 kg) or a larger quantity,
4.2 Spacing Rods—Two joint-thickness spacing rods made such as a 50 or 100-lb (23 or 45-kg) bag from which a 10-lb
of ⁄16-in. (2-mm) diameter drill rod cut into 4-in. (102-mm)
(4.5 kg) sample may be obtained using acceptable sampling
lengths. procedures. The 10-lb (4.5 kg) sample should be thoroughly
4.3 Oven—A drying oven to accommodate at least five 9-in.
mixed with water to a uniform, troweling consistency and
(230-mm) straight brick standing on end, and for use at 220 to stored in a covered container (resistant to possible corrosive
230°F (105 to 110°C).
action by the mortar) for at least 16 h prior to the test.
4.4 Testing Machine—A standard mechanical or hydraulic
NOTE 1—Reaction of phosphoric acid or aluminum phosphate with
compression testing machine conforming to the requirements
metallics may cause the development of hydrogen gas in some mortars.
of Practices E 4 and having a sensitivity of 20 lbf or less in the
Therefore, the container should be covered only to minimize moisture
range from 0 to 4000 lbf (17.8 kN) may be used.
loss, not tightly sealed.
4.5 Loading Fixture—The fixtures shall provide load bear-
ing blocks which ensure that the forces are applied normal to
6. Procedure
the beam without eccentricity. The directions of loads and
6.1 Cut each of the bricks of the sample (see Note 2) into
reactions may be maintained parallel by judicious use of
1 1
two equal parts on a plane parallel to the 2 ⁄2 by 4 ⁄4-in. (65 by
linkages, roller bearings, and flexure plates. Eccentricity of
1 1
114-mm) face. Use the uncut 2 ⁄2by-4 ⁄4 in. face of each dry
loading can be avoided by the use of spherical bearings.
half-br
...