ASTM D7263-21

This document is not an ASTM standard and is intended only to provide the user of an ASTM 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: D7263 − 09 (Reapproved 2018) D7263 − 21
Standard Test Methods for
Laboratory Determination of Density (Unit Weight) and Unit
Weight of Soil Specimens
This standard is issued under the fixed designation D7263; 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.
ε NOTE—Editorially updated units of measurement statement in April 2018.
ε NOTE—Changes were editorially made in June 2018.
1. Scope Scope*
1.1 These test methods describe two ways of determining the total/moist total/moist/bulk density, dry density, and dry densities
(unit weights) unit weight of intact, disturbed, remolded, and reconstituted (compacted) soil specimens. Densityspecimens (Note
1 (unit weight) as used in this standard means the same as “bulk density” of soil as defined by the Soil Science Society of America.
). Intact specimens may be obtained from thin-walled sampling tubes, block samples, or clods. Specimens that are remolded by
dynamic or static compaction procedures mayare also be measured by these methods. These methods apply to soils that will retain
their shape during the measurement process and may also apply to other materials such as soil-cement, soil-lime, soil-bentonite
or solidified soil-bentonite-cement slurries. It is common for the density (unit weight) of specimens after removal from sampling
tubes and compaction molds to be less than the value based on tube or mold volumes, or of in situ conditions. This conditions after
removal of the specimen from sampling tubes and compaction molds. This change is due to the specimen swelling after removal
of lateral pressures.
NOTE 1—The adjectives total, moist, wet or bulk are used to represent the density condition. In some professions, such as Soil Science and Geology, the
term “bulk density” usually has the same meaning as dry density. In the Geotechnical and Civil Engineering professions, the preferred adjective is total
over moist and bulk when referring to the total mass of partially saturated or saturated soil or rock per unit total volume. For more detailed information
regarding the term density, refer to Terminology D653.
1.1.1 Method A (Water Displacement)—Method A covers the procedure for measuring the volume of wax coated specimens A
specimen is coated in wax and then placed in water to measure the volume by determining the quantity of water displaced. The
density and unit weight are then calculated based on the mass and volume measurements. Do not use this method if the specimen
is susceptible to surface wax intrusion.
1.1.1.1 This method only applies to specimens in which the wax will not penetrate the outer surface of the specimen.
1.1.2 Method B (Direct Measurement)—Method B covers the procedure by means of the direct measurement of the dimensions
and mass of a specimen, usually one of cylindrical The dimensions and mass of a specimen are measured. The density and unit
weight are then calculated using these direct measurements. Usually, the specimen has a cylindrical or cuboid shape. Intact and
reconstituted/remolded specimens may be tested by this method in conjunction with strength, permeability permeability/hydraulic
conductivity (air/water) and compressibility determinations.
These test methods are under the jurisdiction of ASTM Committee D18 on Soil and Rock and are the direct responsibility of Subcommittee D18.03 on Texture, Plasticity
and Density Characteristics of Soils.
Current edition approved Feb. 15, 2018Jan. 1, 2021. Published March 2018January 2021. Originally approved in 2009 as D7263–09. Last previous edition approved in
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20092018 as D7263D7263–09(2018) –09. DOI: 10.1520/D7263-09R18E02.10.1520/D7263-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7263 − 21
1.2 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided
for information only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as
nonconformance with this standard.
1.2.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In the system, the pound (lbf)
represents a unit of force (weight), while the units for mass is slugs. The slug unit is not given, unless dynamic (F = ma)
calculations are involved.
1.2.2 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass
(lbm) and of force (lbf). This practice implicitly combines two separate systems of units; the absolute and the gravitational systems.
It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. As stated, this
standard includes the gravitational system of inch-pound units and does not use/present the slug unit of mass. However, the use
of balances and scales recording pounds of mass (lbm) or recording density in lbm/ft shall not be regarded as nonconformance
with this standard.
1.2.3 The terms density and unit weight are often used interchangeably. Density is mass per unit volume, whereas unit weight is
force per unit volume. In this standard, density is given only in SI units. After the density has been determined, the unit weight
is calculated in SI or inch-pound units, or both.
1.3 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026., unless superseded by this test method.
1.3.1 The methodprocedures used to specify how data are collected, calculated, collected/recorded or recordedcalculated in this
standard is not directly related to the accuracy with which the data can be applied in design or other uses, or both. How one applies
the results obtained using this standard is beyond its scope.are regarded as the industry standard. In addition, they are representative
of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for
obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase
or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard
to consider significant digits used in analysis methods for engineering design.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
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D698 Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft (600 kN-m/m ))
D854 Test Methods for Specific Gravity of Soil Solids by Water Pycnometer
D1557 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft (2,700
kN-m/m ))
D1587/D1587M Practice for Thin-Walled Tube Sampling of Fine-Grained Soils for Geotechnical Purposes
D2166/D2166M Test Method for Unconfined Compressive Strength of Cohesive Soil
D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
D2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)
D2488 Practice for Description and Identification of Soils (Visual-Manual Procedures)
D3550/D3550M Practice for Thick Wall, Ring-Lined, Split Barrel, Drive Sampling of Soils
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D4220/D4220M Practices for Preserving and Transporting Soil Samples
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.
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D4318 Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils
D4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and Construction
Materials Testing
D4943 Test Method for Shrinkage Factors of Cohesive Soils by the Water Submersion Method
D6026 Practice for Using Significant Digits in Geotechnical Data
E2251D7015/D7015M Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision LiquidsPractices for
Obtaining Intact Block (Cubical and Cylindrical) Samples of Soils
2.2 Other Reference:
Soil Science Society of America Glossary of Soil Science Terms
3. Terminology
3.1 For definitions of common technical terms used in this standard, refer to Terminology D653.
4. Summary of Test Methods
4.1 Test Method A (Water Displacement)—A test specimen is obtained from a sample, then its mass in air is measured. It is then
coated in wax and its mass is measured. The wax-coated specimen is then placed in a wire basket that is attached to a balance and
fully submerged in a container (water tank) of water. Its mass in water is measured. The quantity of water displaced measures the
volume of the specimen. The density and unit weight are then calculated. This method must not be used for specimens that allow
wax to penetrate the outer surface of the specimen
4.2 Test Method B (Direct Measurement)—A test specimen is obtained from a sample. The test specimen can have a cylindrical
or cuboidal shape. If the test specimen is cylindrical in shape, its mass, height, and diameter are measured. If it is cuboidal in shape,
its mass, height, width, and length are measured. The density and unit weight are then calculated based on the physical dimensions
and mass of the specimen.
5. Significance and Use
5.1 Dry density, as defined as “density of soil or rock” in TerminologyDensity is a key element in the D653 and “bulk density”
by soil scientists, can be used to convert the water fraction of soil from a mass basis to a volume basis and vise-versa. phase
relations, phase relationships, or mass-volume relationships of soil and rock (Appendix X1). When particle density, that is, specific
gravity (Test Methods D854) is also known, dry density can be used to calculate porosity and void ratio (see Appendix X1). Dry
density measurements are also useful for determining degree of soil compaction. Since moisturewater content is variable,
moisttotal/moist soil density provides little useful information except to estimate the weight of soil per unit volume, for example,
poundsgrams per cubic yard,centimeter, at the time of sampling. Since soil volume shrinks with drying of swelling soils, bulktotal
density will vary with moisturewater content. Hence, the water content of the soil should be determined at the time of sampling.
5.2 Densities (unit weights) and unit weights of remolded/reconstituted specimens are commonly used to evaluate the degree of
compaction of earthen fills, embankments, etc. and the like. Dry density values are usually used in conjunction with compaction
curve values used to calculate dry unit weight values to create a compaction curve (Test Methods D698 and D1557).
4.3 Density (unit weight) is one of the key components in determining the mass composition/phase relations of soil, see Appendix
X1.
NOTE 2—The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective
testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable
results depend on several factors; Practice D3740 provides a means of evaluating some of these factors.
6. Apparatus
6.1 Balance—Balances must conform to the requirements of Guide D4753.
6.1.1 To measure the mass of the specimen, the balance shall have readability without estimation of 0.01 g. For Method A, the
capacity of this balance will need to exceed the mass of the specimen suspended in water. A balance having a below-balance port
using a weighing hook or a yoke assemblage for top loading balances is typically used to make this measurement. For Method B,
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the capacity of this balance will need to exceed the mass of the specimen plus mold, if applicable. In general, a balance with a
minimum capacity of 1000 g is sufficient. A higher capacity balance may be needed when determining the mass of an un-extruded
specimen.
6.2 Drying Oven—A vented, thermostatically controlled, preferably of the forced-draft type, oven capable of maintaining a
uniform temperature of 110 6 5°C (230 6 9°F) throughout the drying chamber.
6.3 Wax (Method A)—Non-shrinking paraffin, microcrystalline, or other suitable wax mixture that does not become brittle when
dry and does not shrink during solidification. The density of the wax must be known to three significant digits and have a relatively
constant density, ρ , (Note 3). The density must not appreciably change after repeated melting and solidification cycles. Determine
x
the density of the wax following the procedure given in Test Method D4943, Annex A2.
6.3.1 The density of the wax can often be obtained from the manufacturer, but shall be determined in accordance with the
procedure given in Test Method D4943, Annex A2 before initial use and after replenishment of stock. To verify the density of the
wax is not changing by more than 0.0025 g/cm after repeated cycles, perform the procedure three times in a row to determine
the density of each heating and cooling cycle. The density values should not vary more than 0.0025 g/cm .
NOTE 3—A 50/50 mixture of paraffin wax and petroleum jelly by mass has been demonstrated to provide an adequate alternative. Paraffin wax is
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commercially available and has a typical density of 900 kg/m (0.900 g/cm ).
6.4 Wax-Melting Container (Method A)—Any container or device capable of melting the wax without overheating the wax.
Heating using hot water and a container/device that is thermostatically controlled is preferred.
6.5 Wire Basket (Method A)—For Method A the following apparatus are required:A wire basket of 3.35 mm (0.132 in.) or finer
mesh of approximately equal width and height of sufficient size to contain the specimen. The basket shall be constructed to prevent
trapping air when it is submerged. A hairnet may also be used in lieu of the basket for smaller soil specimens.
5.1.1 Balance—All balances must meet the requirements of Specification D4753 and this section. A Class GP1 balance of 0.01
g readability is required for specimens having a mass up to 200 grams and a Class GP2 balance of 0.1 g readability is required
for specimens having a mass over 200 grams. For method A, the balance must be capable of measuring the mass of the specimen
suspended in water. This is usually accomplished by a weighing hook built into the balance for that purpose, or a yoke assemblage
is placed upon the pan which suspends a thin, non-absorbent string or wire, that is, a nylon line, etc., below the balance into the
water reservoir.
5.1.2 Drying Oven—A thermostatically controlled, preferably of the forced-draft type, capable of maintaining a uniform
temperature of 110 6 5°C throughout the drying chamber.
5.1.3 Wax—Non-shrinking, paraffin and/or microcrystalline wax that has a known and constant density, ρ , to four significant
ρ
figures and that does not change after repeated melting and cooling cycles.
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NOTE 2—The waxes generally used are commercially available and have density values in the range of 0.87 to 0.91 g/cm or Mg/m .
5.1.4 Wax-Melting Container—Used to melt the wax, but should not allow the wax to overheat. A container heated by hot water,
preferably thermostatically controlled, is satisfactory. The wax should be heated to only slightly above the melting point to avoid
flashing of the wax vapors and to permit quickly forming a uniform surface coating of wax. Warning—Vapors given off by molten
wax ignite spontaneously above 205°C (400°F) and should not be allowed to come in contact with the heating element or open
flame.
5.1.5 Wire Basket—A wire basket of 3.35 mm or finer mesh of approximately equal width and height of sufficient size to contain
the specimen. The basket shall be constructed to prevent trapping air when it is submerged. The basket is suspended from the
balance by a fine thread or string. A hairnet may also be used in lieu of the basket for smaller soil specimens.
5.1.6 Container—A container or tank of sufficient size to contain the submerged basket and specimen.
5.1.7 Specimen Container—A corrosion-resistant container of sufficient size to contain the specimen for water content
determination.
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5.1.8 Thermometer—Capable of measuring the temperature range within which the test is being performed graduated in a 0.1
degree C division scale and meeting the requirements of Specification E2251.
5.1.9 Container Handling Apparatus—Gloves or suitable holder for moving and handling hot containers.
5.1.10 Miscellaneous—Paintbrush, trimming tools, specimen containers, and data sheets provided as required.
6.6 Water Tank (Method A)—A watertight container or tank of sufficient size to contain the submerged basket and specimen.
6.7 Thermometric Device (Method A)—A thermometric device capable of measuring the temperature range within which the test
is being performed readable to 0.1°C or better and having an accuracy of at least 60.5°C.
6.8 Specimen-Size Measurement Devices (Method B)—For Method B the following apparatus are needed:Devices used to measure
the physical dimensions, such as height, width, length, and diameter, of the specimen to four significant digits. The devices shall
be constructed such that their use will not disturb/deform, indent, or penetrate the specimen.
5.2.1 Balance—See 5.1.1.
5.2.2 Drying Oven—See 5.1.2.
5.2.3 Specimen-Size Measurement Devices—Devices used to determine the height and width or diameter of the specimen shall
measure the respective dimensions to four significant digits and shall be constructed so that their use will not indent or penetrate
into the specimen.
NOTE 4—Circumferential measuring tapes are recommended over calipers for measuring the diameter of cylindrical specimens.
5.2.4 Apparatus for Preparing Reconstituted or Remolded Specimens (Optional)—Such apparatus is only required if these types
of specimens are being tested.
5.2.5 Miscellaneous Apparatus—Specimen trimming and carving tools including a wire saw, steel straightedge, miter box and
vertical trimming lathe, specimen containers, and data sheets shall be provided as required.
6.9 Miscellaneous—Items such as, a paintbrush, trimming and carving tools (such as a wire saw, steel straightedge, miter box and
vertical trimming lathe), apparatus for preparing remolded or reconstituted specimens, sample extruder, specimen containers for
water contents, plastic wrap, aluminum foil, plastic bags, gloves, and tongs, may be necessary or useful, or both.
7. Samples and Test Specimens
7.1 Samples—Intact samples shall be preserved and transported in accordance with Practice D4220/D4220M Groups C and D soil.
Compacted D, except if the as-received sample does not meet those requirements. Reconstituted or remolded specimens shall be
preserved in accordance with Practice D4220/D4220M Group B soil. Maintain the samples that are stored B, except if the
as-received sample does not meet those requirements. Maintain stored samples prior to testing in non-corrodible airtight containers
at a temperature between approximately 3°3°C and 30°C (37.4°F and 86°F) in an area that prevents direct contact with sunlight.
Preserve the sample at its original moisture condition unless excluded above, and at no time shall the sample be allowed to undergo
undesirable temperature changes such as freezing or heating.
7.2 Specimens—Specimens Size—Specimens for testing shall Cylindrical specimens must have a minimum diameter of 33 mm
(1.3 in.) and be sufficiently cohesive and firmable to maintain shape during the measuring procedure if Method A is used,
seeprocedure. The average height to average diameter ratio should, but is not required 1.1.1.1. Specimens shall to, be between 2
and 2.5. The largest particle size must be smaller than ⁄6have a minimum dimension of 30 the specimen diameter.
Cubical/Cuboidal specimens must have minimum dimensions (height, width, and length) of 33 mm (1.3 in.) and the largest particle
contained within the test specimen shall size must be smaller than one-tenth ⁄10 of the specimen’s smallest dimension. For
specimens having a dimension of 72 mm (2.8 in.) or larger, the largest particle size shall be smaller than one-sixth of the
specimen’s specimen’s smallest dimension. If, after completion of a test on an intact specimen, visual observations indicate that
larger particles than permitted it is found based on visual observation that oversize particles are present, indicate this information
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in the remarks section of the report of test data.data sheet. Irregular shaped (clods) specimens must be of sufficient size to
adequately represent the soil under evaluation. Avoid selecting a specimen that is too small since it would not be representative.
7.3 Intact Specimens—Prepare intact specimens from large intact samples (Practice D7015/D7015M), from samples secured in
accordance with Practice D1587/D1587M, or other acceptable intact tube sampling procedures. Specimens obtained by tube
sampling may be tested without extrusion or trimming except for cutting the end surfaces plane and perpendicular to the
longitudinal axis of the specimen, provided soil characteristics are such that no significant disturbance results from sampling.
Specimens can also be obtained from intact block samples using a sharp cutting ring. Handle specimens carefully to reduce the
potential for disturbance, changes in cross section, or changes in water content. If compression or any type of noticeable
disturbance would be caused by the extrusion device, split the sample tube lengthwise or cut the tube in suitable sections to
facilitate removal of the specimen with minimum disturbance. Prepare trimmed specimens, in an environment such as a controlled
high-humidity room where soil water content change is avoided. Where removal of pebbles or crumbling resulting from trimming
causes voids on the surface of the specimen, carefully fill the voids with remolded soil obtained from the trimmings. When the
sample condition permits, a vertical trimming lathe may be used to reduce the specimen to a smaller diameter if desired. After
obtaining the desired diameter, place the specimen in a miter box, and cut the specimen to the final height with a wire saw or other
suitable device. Trim the surfaces with the straightedge. Perform and record one or more water content determinations to the
nearest 0.1 % on material trimmed from the specimen in accordance with Test Methods D2216.
NOTE 5—Core sampling might be difficult or impossible in gravelly or hard dry soils. Wet soils tend to be more plastic and subject to compression.
NOTE 6—Some soils may expand into the sampling tube with a resultant change in volume from the original in situ condition.
7.3.1 Cubical/Cuboidal specimens must be prepared such that the sides are relatively flat and even. Trimming devices that assist
in creating a smooth, flat surface should be used.
7.4 Reconstituted (Compacted) Specimens—Soil needed for reconstituted specimens shall be thoroughly mixed with sufficient
water to produce the desired water content. If water is added to the soil, store the material in a covered container for at least 16
h prior to compaction. Reconstituted specimens may be prepared by compacting material in at least six layers using a split mold
of circular cross section having dimensions meeting the requirements enumerated in 7.2 for cylindrical specimens. Specimens may
be reconstituted to the desired density by either: (1) kneading or tamping each layer until the accumulative mass of the soil placed
in the mold is reconstituted to a known volume; or (2) by adjusting the number of layers, the number of tamps per layer, and the
force per tamp. The top of each layer shall be scarified prior to the addition of material for the next layer. The tamper used to
compact the material shall have a diameter equal to or less than one half the diameter of the mold. After a specimen is formed,
with the ends perpendicular to the longitudinal axis, remove the mold. Perform and record one or more water content
determinations to the nearest 0.1 % on excess material used to prepare the specimen in accordance with Test Methods D2216.
7.5 Remolded Specimens—Specimens may be prepared either from a failed intact specimen or from a disturbed sample, providing
it is representative of the failed intact specimen. In the case of failed intact specimens, wrap the material in a thin rubber membrane
and work the material thoroughly with the fingers to make sure of complete remolding. Avoid entrapping air in the specimen.
Exercise care to obtain a uniform density, to remold to the same void ratio as the intact specimen, and to preserve the water content
of the soil. Form the disturbed material into a mold of circular cross section having dimensions meeti
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