ASTM C604-02(2007)e1

This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
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Designation:C 604–98 Designation: C 604 – 02 (Reapproved 2007)
Standard Test Method for
True Specific Gravity of Refractory Materials by Gas-
Comparison Pycnometer
This standard is issued under the fixed designation C 604; 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.
´ NOTE—Units of measure statement was added editorially in March 2009.
1. Scope
1.1 This test method covers the determination of the true specific gravity of solid materials, and is particularly useful for
materials that easily hydrate which are not suitable for test with Test Method C 135. This test method may be used as an alternate
for Test Method C 135, Test Method C 128, and Test Method C 188 for determining true specific gravity.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.2.1 Exception—In 7.3 the equivalent SI unit is expressed in parenthesis.
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.
2. Referenced Documents
2.1 ASTM Standards:
C 128 Test Method for Specific Gravity andAbsorption of FineAggregate Test Method for Density, Relative Density (Specific
Gravity), and Absorption of Fine Aggregate
C 135 Test Method for True Specific Gravity of Refractory Materials by Water Immersion
C 188 Test Method for Density of Hydraulic Cement
3. Summary of Test Method
3.1 The sample is powdered to ensure permeation of gas into all pores. For practical purposes this is assumed to be true when
the sample passes a No. 325 (45-µm) sieve. The volume of a carefully weighed powdered sample which has first been heated to
drive off moisture and undesired combined water is measured by the gas-comparison pycnometer. Density is calculated from the
sample weight in grams divided by its volume in cubic centimetres. This is also the specific gravity of the sample at room
temperature compared to water at 4°C.
3.2 The principle of the gas-comparison pycnometer is as follows: There are two chambers and two pistons as sketched in Fig.
1. For purposes of illustration, the chambers are assumed to be equal in volume, and there is no sample in either cylinder. Under
these conditions, with the coupling valve closed, any change in the position of one piston must be duplicated by an identical stroke
in the other in order to maintain the same pressure on each side of the differential pressure indicator.
3.3 If a sample, V , is inserted into chamber B , the coupling valve closed and both pistons advanced the same amount from
x
position 1 to position 2, the pressures will not remain the same. However the pressures can be maintained equal if piston B instead
is moved only to position 3. Then the remaining displacement d , from position 3 to position 2, is equal to the volume of the
x
sample, V . If piston A always is advanced exactly the same distance each time a measurement is made, the distance that piston
x
B differs from position 2, when the pressures in both cylinders are equal, will always be proportional to the volume, V . The
x
distance (d ) between positions 2 and 3 can be calibrated and made to read directly in terms of cubic centimetres, employing a
x
digital counter.
This test method is under the jurisdiction of ASTM Committee C-8 on Refractories, and is the direct responsibility of Subcommittee C08.03 on Physical Test and
Properties.
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Current edition approved Sept. 10, 1998. Published December 1998. Originally published as C604–67. Last previous edition C604–86 (Reapproved 1993) .
This test method is under the jurisdiction of ASTM Committee C08 on Refractories and is the direct responsibility of Subcommittee C08.03 on Physical Properties.
Current edition approved March 1, 2007. Published April 2007. Originally approved in 1967. Last previous edition approved in 2002 as C 604 – 02.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. ForAnnualBookofASTMStandards
, Vol 04.02.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C 604 – 02 (2007)
FIG. 1 Simplified Schematic Diagram
4. Significance and Use
4.1 The true specific gravity of a material is the ratio of its true density, determined at a specific temperature, to the true density
of water, determined at a specific temperature. Thus, the true specific gravity of a material is a primary property which is related
to chemical and mineralogical composition.
4.2 This test method is particularly useful for hydratable materials which are not suitable for test with Test Method C 135.
4.3 For refractory raw materials and products the true specific gravity is a useful value for: classification, detecting differences
in chemical composition between supposedly like samples, indicating mineralogical phases or phase changes, calculating total
porosity when the bulk density is known, and for any other test method that requires this value for the calculation of results.
4.4 This test method is a primary standard method which is suitable for use in specifications, quality control, and research and
development. It can also serve as a referee test method in purchasing contracts or agreements.
4.5 Fundamental assumptions inherent in this test method are the following:
4.5.1 The sample is representative of the material in general,
4.5.2 The total sample has been reduced to the particle size specified,
4.5.3 No contamination has been introduced during processing of the sample,
4.5.4 The ignition of the sample has eliminated all free or combined water without inducing sintering or alteration,
4.5.5 An inert gas (helium) has been used in the test, and
4.5.6 The test method has been conducted in a meticulous manner.
4.5.7 Deviation from any of these assumptions negates the usefulness of the results.
4.6 Ininterpretingtheresultsofthistestmethoditmustberecognizedthatthespecifiedsampleparticlesizeissignificantlyfiner
than specified for Test Method C 135. Even this finer particle size for the sample does not preclude the presence of some closed
pores, and the amount of residual closed pores may vary between materials or even between samples of the same or like materials.
The values generated by this test method may, therefore, be very close approximations rather than accurate representations of true
specific gravities. Thus, comparisons of results should only be judiciously made between like materials
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