ASTM C128-22

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Designation: C128 − 15 C128 − 22
Standard Test Method for
Relative Density (Specific Gravity) and Absorption of Fine
Aggregate
This standard is issued under the fixed designation C128; 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.
1. Scope Scope*
1.1 This test method covers the determination of relative density (specific gravity) and the absorption of fine aggregates. The
relative density (specific gravity), a dimensionless quality, is expressed as oven-dry (OD), saturated-surface-dry (SSD), or as
apparent relative density (specific gravity). The OD relative density is determined after drying the aggregate. The SSD relative
density and absorption are determined after soaking the aggregate in water for a prescribed duration.
1.2 This test method is not intended to be used for lightweight aggregates that comply with Specification C332 Group I aggregates.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 The text of this test method references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of this test method.
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C29/C29M Test Method for Bulk Density (“Unit Weight”) and Voids in Aggregate
C70 Test Method for Surface Moisture in Fine Aggregate
C117 Test Method for Materials Finer than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing
C125 Terminology Relating to Concrete and Concrete Aggregates
C127 Test Method for Relative Density (Specific Gravity) and Absorption of Coarse Aggregate
C188 Test Method for Density of Hydraulic Cement
C330C330/C330M Specification for Lightweight Aggregates for Structural Concrete
C332 Specification for Lightweight Aggregates for Insulating Concrete
This test method is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregatesand is the direct responsibility of Subcommittee C09.20 on
Normal Weight Aggregates.
Current edition approved Jan. 1, 2015Dec. 15, 2022. Published March 2015January 2023. Originally approved in 1936. Last previous edition approved in 20122015 as
C128–12.–15. DOI: 10.1520/C0128-15.10.1520/C0128-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
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C128 − 22
C188 Test Method for Density of Hydraulic Cement
C566 Test Method for Total Evaporable Moisture Content of Aggregate by Drying
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C702C702/C702M Practice for Reducing Samples of Aggregate to Testing Size
C1252 Test Methods for Uncompacted Void Content of Fine Aggregate (as Influenced by Particle Shape, Surface Texture, and
Grading)
D75 Practice for Sampling Aggregates
D854 Test Methods for Specific Gravity of Soil Solids by Water Pycnometer
2.2 AASHTO Standard:
AASHTO T 84 Specific Gravity and Absorption of Fine Aggregates
3. Terminology
3.1 Definitions—For definitions of terms used in this standard, refer to Terminology C125.
4. Summary of Test Method
4.1 A sample of aggregate is immersed in water for 2424 h 6 4 h to essentially fill the pores. It is then removed from the water,
the water is dried from the surface of the particles, and the mass determined. Subsequently, the sample (or a portion of it) is placed
in a graduated container and the volume of the sample is determined by the gravimetric or volumetric method. Finally, the sample
is oven-dried and the mass determined again. Using the mass values thus obtained and formulas in this test method, it is possible
to calculate relative density (specific gravity) and absorption.
5. Significance and Use
5.1 Relative density (specific gravity) is the ratio of mass of an aggregate to the mass of a volume of water equal to the volume
of the aggregate particles – also referred to as the absolute volume of the aggregate. It is also expressed as the ratio of the density
of the aggregate particles to the density of water. Distinction is made between the density of aggregate particles and the bulk
density of aggregates as determined by Test Method C29/C29M, which includes the volume of voids between the particles of
aggregates.
5.2 Relative density is used to calculate the volume occupied by the aggregate in various mixtures containing aggregate including
hydraulic cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis.
Relative density (specific gravity) is also used in the computation of voids in aggregate in Test Method C29/C29M and in Test
Method C1252. Relative density (specific gravity) (SSD) is used in the determination of surface moisture on fine aggregate by
displacement of water in Test Method C70. Relative density (specific gravity) (SSD) is used if the aggregate is in a saturated
surface-dry condition, that is, if its absorption has been satisfied. Alternatively, the relative density (specific gravity) (OD) is used
for computations when the aggregate is dry or assumed to be dry.
5.3 Apparent relative density (specific gravity) pertain to the solid material making up the constituent particles not including the
pore space within the particles that is accessible to water. This value is not widely used in construction aggregate technology.
5.4 Absorption values are used to calculate the change in the mass of an aggregate material due to water absorbed in the pore
spaces within the constituent particles, compared to the dry condition, if it is deemed that the aggregate has been in contact with
water long enough to satisfy most of the absorption potential. The laboratory standard for absorption is that obtained after
submerging dry aggregate for a prescribed period of time. Aggregates mined from below the water table commonly have a moisture
content greater than the absorption determined by this test method, if used without opportunity to dry prior to use. Conversely,
some aggregates that have not been continuously maintained in a moist condition until used are likely to contain an amount of
absorbed moisture less than the 24-h24–h soaked condition. For an aggregate that has been in contact with water and that has free
moisture on the particle surfaces, the percentage of free moisture is determined by deducting the absorption from the total moisture
content determined by Test Method C566 by drying.
5.5 The general procedures described in this test method are suitable for determining the absorption of aggregates that have had
Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
http://www.transportation.org.
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conditioning other than the 24-h soak, such as boiling water or vacuum saturation. The values obtained for absorption by other test
methods will be different than the values obtained by the prescribed 24-h soak, as will the relative density (specific gravity) (SSD).
6. Apparatus
6.1 Balance—A balance or scale having a capacity of 1 kg 1 kg or more, sensitive to 0.1 g 0.1 g or less, and accurate within 0.1 %
of the test load at any point within the range of use for this test method. Within any 100-g100 g range of test load, a difference
between readings shall be accurate within 0.1 g.
6.2 Pycnometer (for Use with Gravimetric Procedure)—A flask or other suitable container into which the fine aggregate test
sample can be readily introduced and in which the volume content can be reproduced within 6 0.1 6 0.1 cm . The volume of the
container filled to mark shall be at least 50 % greater than the space required to accommodate the test sample. A volumetric flask
of 500-cm500 cm capacity or a fruit jar fitted with a pycnometer top is satisfactory for a 500-g500 g test sample of most fine
aggregates.
6.3 Flask (for Use with Volumetric Procedure)—A Le Chatelier flask as described in Test Method C188 is satisfactory for an
approximately 55-g55 g test sample.
6.4 Temperature Measuring Device—Capable of measuring the temperature of the water within the specified range and accurate
to 6 1 °C with readability or graduations of 0.5 °C or better.
6.5 Mold and Tamper for Surface Moisture Test—The metal mold shall be in the form of a frustum of a cone with dimensions as
follows: 4040 mm 6 3-mm3 mm inside diameter at the top, 906 3-mm 90 mm 6 3 mm inside diameter at the bottom, and
7575 mm 6 3 mm 3 mm in height, with the metal having a minimum thickness of 0.8 mm. The metal tamper shall have a mass
of 340340 g 6 15 g 15 g and a flat circular tamping face 2525 mm 6 3 mm in diameter.
6.6 Oven—An oven of sufficient size, capable of maintaining a uniform temperature of 110110 °C 6 5 °C (230(230 °F 6 9 °F).
7. Sampling
7.1 Sample the aggregate in accordance with Practice D75. Thoroughly mix the sample and reduce it to obtain a test specimen
of approximately 1 kg using the applicable procedures described in Practice C702C702/C702M.
8. Preparation of Test Specimen
8.1 Place the test specimen in a suitable pan or vessel and dry in the oven to constant mass at a temperature of 110 6 5 °C (230
6 9 °F). Allow it to cool to comfortable handling temperature (approximately 50 °C), cover with water, either by immersion or
by the addition of at least 6 % moisture to the fine aggregate, and permit to stand for 2424 h 6 4 h. When Specification
C330C330/C330M or Specification C332 Group II lightweight aggregates are used, immerse the aggregate in water at room
temperature for a period of 7272 h 6 4 h, stirring for at least one minute every 24 h.
8.1.1 When the absorption and relative density (specific gravity) values are to be used in proportioning concrete mixtures in which
the aggregates will be in their naturally moist condition, the requirement in 8.1 for initial drying is optional, and, if the surfaces
of the particles in the sample have been kept continuously wet until tested, the requirement in 8.1 for 2424 h 6 4 h soaking or
7272 h 6 4 h is also optional.
NOTE 1—Values for absorption and for relative density (specific gravity) (SSD) may be significantly higher for aggregate not oven dried before soaking
than for the same aggregate treated in accordance with 8.1.
8.2 Decant excess water with care to avoid loss of fines (see also Appendix X1), spread the sample on a flat nonabsorbent surface
exposed to a gently moving current of warm air, and stir frequently to secure homogeneous drying. Employ mechanical aids such
as tumbling or stirring to assist in achieving the saturated surface-dry condition, if desired. Continue this operation until the test
specimen approaches a free-flowing condition. Follow the procedure in 8.3 to determine if surface moisture is still present on the
constituent fine aggregate particles. Make the first trial for surface moisture when there is still some surface water in the test
specimen. Continue drying with constant stirring and test at frequent intervals until the test indicates that the specimen has reached
a surface-dry condition. If the first trial of the surface moisture test indicates that moisture is not present on the surface, it has been
C128 − 22
dried past the saturated surface-dry condition. In this case, thoroughly mix a few millilitres of water with the fine aggregate and
permit the specimen to stand in a covered container for 30 min. Then resume the process of drying and testing at frequent intervals
for the onset of the surface-dry condition.
8.3 Test for Surface Moisture—Hold the mold firmly on a smooth nonabsorbent surface with the large diameter down. Place a
portion of the partially dried fine aggregate loosely in the mold by filling it to overflowing and heaping additional material above
the top of the mold by holding it with the cupped fingers of the hand holding the mold. Lightly tamp the fine aggregate into the
mold with 25 light drops of the tamper. Start each drop approximately 5 mm above the top surface of the fine aggregate. Permit
the tamper to fall freely under gravitational attraction on each drop. Adjust the starting height to the new surface elevation after
each drop and distribute the drops over the surface. Remove loose sand from the base and lift the mold vertically. If surface
moisture is still present, the fine aggregate will retain the molded shape. Slight slumping of the molded fine aggregate indicates
that it has reached a surface-dry condition.
8.3.1 Some fine aggregate with predominately angular-shaped particles or with a high proportion of fines does not slump in the
cone test upon reaching the surface-dry condition. Test by dropping a handful of
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