ASTM C903-98
(Practice)Standard Practice for Preparing Refractory Castable Specimens by Cold Gunning
Standard Practice for Preparing Refractory Castable Specimens by Cold Gunning
SCOPE
1.1 This practice covers a procedure for preparing refractory concrete specimens containing calcium aluminate cement with or without metal fibers by cold nozzle-mix gunning. Specimens prepared in accordance with this practice are intended for use in standard ASTM test methods required for evaluating gunned materials.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are provided 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: C 903 – 98
Standard Practice for
Preparing Refractory Castable Specimens by Cold Gunning
This standard is issued under the fixed designation C 903; 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 3.5 Although this practice is specifically designed for re-
fractory castables containing calcium aluminate cement, it may
1.1 This practice covers a procedure for preparing refractory
be used with minor modifications for gun mixes containing
castable specimens usually containing calcium aluminate ce-
other bond systems.
ment with or without metal fibers by cold nozzle-mix gunning.
Specimens prepared in accordance with this practice are
4. Apparatus
intended for use in standard ASTM test methods required for
4.1 Gun, pneumatic nozzle-mix. At least 50 ft (15.2 m) of
evaluating gunned materials.
hose should be available. Acceptable nozzle diameters range
1.2 The values stated in inch-pound units are to be regarded
from 1 to 2 in. (25 to 51 mm).
as the standard. The values given in parentheses are provided
4.2 Air Compressor, capable of delivering sufficient pres-
for information only.
sure and volume to adequately move castable to the gun. The
1.3 This standard does not purport to address all of the
3 3
compressor should be able to supply at least 250 ft (7 m )/min.
safety concerns, if any, associated with its use. It is the
4.3 Forms, suitable nonabsorbent type, which will vary in
responsibility of the user of this standard to establish appro-
size in accordance with the number of samples being prepared,
priate safety and health practices and determine the applica-
but are typically 36 by 36 by 5 ⁄2 in. (915 by 915 by 140 mm).
bility of regulatory limitations prior to use.
Forms should be sized to prevent rebound entrapment. The use
2. Referenced Documents of ⁄2 inch hardware cloth as sidewalls of the form allows most
of the rebound to pass through. This reduces the size of the
2.1 ASTM Standards:
form required to achieve the desired standard sized central
C 401 Classification of Alumina and Alumina-Silicate
portion of 24 by 24 in. (610 by 610 mm).
Castable Refractories
4.4 Suitable eye and hand protection must be worn capable
C 865 Practice for Firing Refractory Concrete Specimens
of protection against high velocity refractory particles and steel
3. Significance and Use fibers.
3.1 The properties of refractory castables can be affected by
5. Procedure
their method of installation. This practice attempts to minimize
5.1 Store the castable to be gunned at 70 to 85°F (20 to
the variables encountered during installation by pneumatic
27°C) for 24 h prior to gunning.
gunning.
5.2 Oil the forms lightly. Typically 10W-30 oil is used.
3.2 This practice provides parameters to produce gunned
Place the form against a rigid surface at an angle of 80 to 90°
specimens for use in other ASTM test methods.
to the horizontal.
3.3 This practice may be used to produce specimens for
5.3 If recommended by the supplier, predampen the castable
acceptance testing, service evaluation, manufacturing control,
by mixing with potable water in a paddle mixer for 1 to 5 min
and research and development.
or follow manufacturer’s specific instructions. In general,
3.4 Differences between various kinds of equipment and the
regular (dense) castables require 2 to 4 % of predampening
differences in procedures and operator techniques may result in
water and lightweight (insulating) castables require 5 to 8 %.
significant variations in the physical properties of the gunned
specimens. It is recommended that the same operator use the
NOTE 1—Castables that contain a high-purity cement may benefit by
same equipment to produce specimens for referee testing
aging for 5 to 10 min after dampening before gunning. This “aging’’
procedure should be used if gunning without it produces excessive
agreed to by the involved testing parties. The specific operating
rebound, dusting, or slumping.
parameters should be shown in the report.
NOTE 2—Treat castables containing metal fibers in a normal manner. If
This practice is under the jurisdiction of ASTM Committee C-8 on Refractories
and is the direct responsibility of Subcommittee C08.09 on Monolithic Refractories.
Current edition approved Nov. 10, 1998. Published January 1999. Originally
published as C 903 – 79. Last previous edition C 903 – 94. Equipment available from Allentown Pneumatic Gun Co., P.O. Box 185,
Annual Book of ASTM Standards, Vol 15.01. Allentown, PA 18105, has been found suitable for
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