Standard Method of Test for

Specific Gravity and Absorption of Aggregate

by Volumetric Immersion Method

AASHTO Designation: TP 77-09 (2011) 1

1. SCOPE
1.1. This method covers the determination of bulk and apparent specific gravity and absorption of fine
and coarse aggregate at 20 ± 1°C (70 ± 2°F) for dry and saturated aggregates.

1.2. This standard may involve hazardous materials, operations, and equipment. This standard does
not purport to address all of the safety concerns associated with its use. It is the responsibility of
whoever uses this standard to consult and establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use.

2. REFERENCED DOCUMENTS
2.1. AASHTO Standards:
 M 231, Weighing Devices Used in the Testing of Materials
 T 2, Sampling of Aggregates
 T 19M/T 19, Bulk Density (“Unit Weight”) and Voids in Aggregate
 T 84, Specific Gravity and Absorption of Fine Aggregate
 T 85, Specific Gravity and Absorption of Coarse Aggregate
 T 248, Reducing Samples of Aggregate to Testing Size
 T 255, Total Evaporable Moisture Content of Aggregate by Drying

3. SIGNIFICANCE AND USE

3.1. Bulk specific gravity is the characteristic generally used for calculations of the volume occupied
by the aggregate in various mixtures containing aggregate including portland cement concrete
(PCC), bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute
volume basis. Bulk specific gravity is also used in the computation of voids in aggregate in
T 19M/T 19. Bulk specific gravity determined on the saturated surface-dry basis is used if the
aggregate is wet, that is, if its absorption has been satisfied. Conversely, the bulk specific gravity
determined on the oven-dry basis is used for computations when the aggregate is dry or assumed
to be dry.

3.2. Apparent specific gravity pertains to the relative density of 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.

3.3. When it is deemed that the aggregate has been in contact with water long enough to satisfy most of
the absorption potential, the absorption values are used to represent the change in the mass of an
aggregate due to water absorbed into the pore spaces within the constituent particles, compared to
the dry condition. The laboratory standard for absorption is that obtained after submerging dry

TS-1c TP 77-1 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
 aggregate for approximately 15 h in water. Aggregates mined from below the water table may
have a higher absorption when used, if not allowed to dry. Conversely, some aggregates when
used may contain an amount of absorbed moisture less than the 15-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 can be determined by deducting the absorption from the total
moisture content determined by T 255 drying.

3.4. Users of this method are encouraged to be cautious in applying the results. Values achieved for
specific gravity and absorption are significantly different from those achieved from T 84 and T 85.
Results from this method will affect the calculated results for volumetrics in hot mix asphalt
(HMA) and absorption in PCC. The user is cautioned to thoroughly evaluate these effects before
implementing this test method. Correlation methods discussed in Appendix X2.1 or X2.2 should
be utilized when the values from this method are to be directly substituted for those from T 84 or
T 85.

4. APPARATUS
4.1. Flask with Plug for Coarse Aggregate—A glass flask with a bulb volume of 3000 to 4000 mL and
a separate plug. The neck of the flask shall be marked with 5 mL graduated increments that
correspond to a precision of at least 0.1 percent of the sample volume. Overall length of the flask
is approximately 760 mm (30 in.). (See Note 1 and Figure 1.)

4.2. Flask for Fine Aggregate—A glass flask with a bulb volume of 2000 mL. The neck of the flask
shall be marked with 1 mL graduated increments that correspond to a precision of at least 0.1
percent of the sample volume. Overall length of the flask is approximately 760 mm (30 in.). (See
Note 1 and Figure 1.)
Note 1—The flask to be used for fine aggregate will have a neck approximately 25 mm (1 in.) in
diameter. The flask used for coarse aggregate will have a neck approximately 51 mm (2 in.) in
diameter. These flasks are available from Humboldt Manufacturing Company, 7300 W. Agatite
Avenue, Norridge, IL 60706.

Figure 1—Typical Flask

TS-1c TP 77-2 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
4.3. Scale with a capacity of at least 10 000 g—The scale shall comply with the requirements in
M 231.

4.4. Minimum 450-mm (18-in.) long rod with dry, absorbent swab.

4.5. Timer that can be read to the nearest second, and that can measure elapsed time up to 24 h.

5. CALIBRATION OF FLASK
5.1. Determine and record the empty weight of the flask, to the nearest gram.

5.2. Fill flask with distilled water at 20 ± 1°C (70.0 ± 2°F) such that the bottom of the meniscus is
exactly even with the zero mark.
Note 2—If a flask does not have a zero mark, add water to the first major graduation (10 mL
mark on a fine aggregate flask); then subtract that amount from the calibrated flask volume in
Equation 1.

5.3. Determine and record the weight of the filled flask to the nearest gram.

5.4. Determine the calibrated volume of the flask as follows:

Vcal = B – A (1)
where:
Vcal = calibrated volume of the flask, mL;
A = weight of empty flask, g; and
B = weight of flask filled with water, g.
Note 3—Due to the definition of a milliliter and a gram (1 milliliter of water weighs 1 gram),
these values can be interchanged without conversions.

6. SAMPLING
6.1. Sampling of aggregate shall be accomplished in accordance with T 2.

7. PREPARATION OF TEST SPECIMEN

7.1. Obtain approximately 2 kg of fine aggregate or 3 kg of coarse aggregate using the applicable
procedures described in T 248.

7.2. Dry the sample in an oven or a suitable pan or vessel to constant mass at a temperature of 110 ±
5°C (230 ± 9°F). Allow it to cool to comfortable handling temperature, without allowing it to re-
absorb any water from the surrounding environment. This can be accomplished by covering the
container with a plate or cover that blocks direct access of the ambient humid air to the cooling
sample.

8. TEST PROCEDURE
8.1. Weigh out 1200 ± 10 g of oven-dry fine aggregate or 2500 ± 50 g of oven-dry coarse aggregate to
be tested. If testing lightweight aggregate, reduce the amount of material to 600 ± 10 g for fine
aggregate, or 900 g ± 10 g for coarse aggregate.

8.2. The actual weight, Wd, of oven dry aggregate should be recorded to the nearest 0.01 grams.

TS-1c TP 77-3 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
8.3. Fill the bottom portion of the flask approximately one half full, by height, with 20 ± 1°C
(70 ± 2°F) distilled water. (See Note 4.)

8.4. Measure out, but do not add, approximately 250 g of 20 ± 1°C (70 ± 2°F) distilled water.
Note 4—The volume of water in Sections 8.2 and 8.3 may need to be adjusted for the individual
flask being used. It is important that during the filling process, the combined initial volume of
water and the dry aggregate not plug the neck of the flask. Therefore, the following procedure is
intended to allow sufficient water for the aggregate to become completely submerged, but to not
rise into the narrow neck of the flask.

8.5. Dry the inside of the neck of the flask with a dry absorbent swab.
Note 5—If the inside of the neck is not completely dry, finer portions of the sample may adhere
to the moisture, plugging the neck of the flask as the sample is added.

8.6. Pour the aggregate sample into the flask as quickly as possible, without plugging the neck.
Note 6—It is recommended that an outside funnel not be used. The sand has a tendency to plug
the smaller hole of the funnel, where it typically pours through the built-in funnel without
plugging.

8.7. Start the timer immediately when the aggregate first hits the water in the flask.

8.8. After all of the sample has been poured into the flask, immediately add enough of the holdback
water measured out in Section 8.3 to raise the water level sufficiently up into the graduated portion
of the neck of the flask, so that the water level does not drop below the graduated portion during
the duration of the test.

8.9. Do not shake, agitate, or otherwise disturb the flask at this time.

8.10. Take the reading of the initial water level, Ri, in the neck of the flask 30 s after the first particle has
entered the water.

8.11. Determine and record the weight of the flask filled with aggregate and water, WT, to 0.01 grams.

8.12. Aggressively shake, roll, and otherwise agitate the flask in order to remove all of the released air.
Place a plug into the neck of the coarse aggregate flask to prevent loss of water during the shaking
and agitation of the flask. Stop shaking and agitating the flask when the timer shows 3 min.

8.13. Allow the flask to remain undisturbed for 2 min.

8.14. Obtain and record the reading of the water level in the neck of the flask at 5 min elapsed time
(from when the aggregate first hits the water).

8.15. It is recommended that water level readings be taken at 10 min, 30 min, 60 min, 2 h, and 4 h
elapsed time (see Note 7). Make sure to agitate all of the air out of the sample, and allow the flask
to settle for at least 2 min before taking each reading. See Appendix X1.
Note 7—It is not critical that the readings are taken at the exact times shown. Record the time the
water level reading is actually made.

8.16. Take the final water level reading, Rfinal, at 25 ± 1 h. It is extremely important that all air released
during the soak period be completely eliminated from the flask before taking the final reading.
Make sure that the flask has been thoroughly and completely shaken and agitated, and then left
undisturbed to allow all of the air to escape from the flask until there is no air left in the system.
Make sure that the air removal process is started early enough to completely eliminate all of the air
within the designated time.

TS-1c TP 77-4 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
9. ABSORPTION
9.1. Calculate the absorption as follows:
Absorption, (%) = [Wabs /Wd] × 100 (2)

where:
Wabs = water absorbed into the sample, (Ri – Rfinal), mL, where
Ri = initial water level reading, mL; and
Rfinal = final water level reading, mL; and
Wd = original dry weight of sample, g.

10. SATURATED BULK SPECIFIC GRAVITY (Ss)

10.1. Calculate the saturated bulk specific gravity as follows:
Ss = (Wd + Wabs)/[Vi – Vw] (3)

where:
Wd = original dry weight of sample, g;
Wabs = water absorbed into the sample, mL;
Vi = initial volume, (Ri + Vcal), mL, where
Vcal = calibrated flask volume, mL;
Vw = volume of test water [WT – (Wd + Wf )], mL, where
WT = total weight of flask, water and sample, g; and
Wf = weight of flask, g.

11. DRY BULK SPECIFIC GRAVITY (Sd)

11.1. Calculate the dry bulk specific gravity as follows:
Sd = Wd /( Vi – Vw) (4)

12. APPARENT DRY SPECIFIC GRAVITY (SA)

12.1. Calculate the apparent dry specific gravity as follows:
Sa = Wd /[(Wd + Wf + Vcal) – (WT – Rfinal)] (5)

13. CONVENTIONAL ABSORPTION

13.1. Use the correlation equation shown in Appendix X2.3 to calculate the conventional absorption for
fine aggregate (T 84) as follows:
( Absorption {from Section 9} × 1.8243) 
Conventional Absorption, (%) =   (6)
 +0.0038 

13.2. Use the correlation procedure in Appendix X2.2 to determine the conventional absorption and
specific gravities for fine or coarse aggregates, according to T 84 or T 85, respectively.
Note 8—The use of either of these methods is at the discretion of the user. The user is
encouraged to use the method of preference.

TS-1c TP 77-5 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
14. REPORT
14.1. Report the specific gravity results to the nearest 0.001, and indicate the type of specific gravity,
whether bulk, bulk (saturated surface-dry), or apparent.

14.2. Report the absorption result to the nearest 0.1 percent. Unless otherwise specified, the end user
shall use the absorption value that is appropriate to the specific application.

APPENDIXES
(Nonmandatory Information)

X1. INTERMEDIATE WATER LEVEL READINGS

X1.1. This test provides an internal quality process check. By plotting the intermediate readings against
time on a logarithmic scale, an approximately straight line should be determined. If the line is not
essentially straight, then something happened during the performance of the test.

X1.2. It also provides the ability to determine the time-rate of absorption relationship for a particular
material. Once the time-rate of absorption plot has been established, it can then be used in the
field. If intermediate levels of absorption are to be acknowledged during the delivery and
construction procedures using this aggregate, the starting and anticipated ending points and their
relative degree of saturation can be taken directly from the resulting plot.

X1.3. A typical plot is shown in Figure X1.1:

2394.0

2392.0

2390.0
Volume (ml)

2388.0

2386.0

2384.0

2382.0

2380.0
0.1 1 10 100 1000 10000

Time (Minutes)

Figure X1.1—Phunque Absorption Test

X1.4. Plot the readings on semi-log paper with the x-axis being time on the logarithmic scale.

X1.5. Example Data:

TS-1c TP 77-6 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
X1.6. A typical datasheet that has been found to work well with this procedure is shown in Figure X1.2.

Source of Sample: ABC Contractor—Concrete

Sand
Tare Weight of Flask, g: 887.90

Calibrated Volume of the Flask, g: 2312.20

Conventional Absorption (T 84/T 85): 0.8%

Conventional Bulk Specific Gravity (SSD) (T 84/T 85): 2.623

Dry Weight of Sample: 1200.00

Total Initial Volume of Water Added: 1937.2

Total Weight of Flask, Sample and Water, g: 4025.10

Total
Volume
Elapsed Time (in min): Readings (mL)
Ri 0.5 78.5 2390.7
5 77.0 2389.2
10 76.5 2388.7
30 76.0 2388.2
60 75.5 2387.7
120 2 Hrs 75.0 2387.2
240 4 Hrs 74.5 2386.7
Rfinal 1440 24.0 Hrs 73.0 2385.2
Technician: [Name of ABC Technician]
Date of Test: [February 14, 2008]

Initial Volume: 2390.7 mL T 84 or T 85

Absorption: 0.5 % 0.8
Bulk Specific Gravity (dry) 2.646 2.601
Bulk Specific Gravity (SSD) 2.658 2.623
Bulk Specific Gravity (apparent) 2.679 2.656

Figure X1.2—Sample of Phunque Absorption Test Datasheet

X2. STATISTICAL CORRELATION WITH T 84

X2.1. The absorption values for fine aggregates determined from this method vary significantly from
those determined by T 84. In many applications the magnitude of effect from using Phunque
values in lieu of the conventional values makes it extremely difficult to proceed with the intended
application. At this time, it is not known which is more accurate. However, the Phunque method is
much more consistent, repeatable, and easier to perform. Therefore, a statistical study was
performed by comparing representative samples of fine aggregate sources throughout the country
and determining the specific gravities and absorptions using both methods concurrently. The
relationship for fine aggregate absorption shown in Figure X2.1 is the result of this effort.

TS-1c TP 77-7 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
 6.00%

5.00%
T 84 Absorption

4.00%

3.00%

2.00%
y = 1.8243x + 0.0038
R 2 = 0.818
1.00%

0.00%
0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00%

Phunque Absorption

Figure X2.1—Absorption Comparison (Fine Aggregate Only)

X2.2. Direct Correlation with T 84 or T 85:

X2.3. In situations where these numbers will be used in significant applications, and where a preliminary
evaluation has not been performed to assess the nature and magnitude of the differences using the
Phunque values in lieu of T 84 or T 85 values, the user is encouraged to perform a source-specific
correlation for each material type from each source or stockpile. This correlation effort should be
performed by using the Phunque method to determine the specific gravities and absorption on at
least three samples split from a single master sample. The process should be repeated using T 84
or T 85 procedures on at least five samples split from the same master sample. Once completed,
the correlation factor, CF, can be calculated as follows:

CF = (Average Conventional Measurements)/(Average Phunque Measurements)

Example: Determine the CF to use in the conventional applications:

(Values taken from Figure X1.2)

Average Phunque Absorption = 0.5 Average T 84 Absorption = 0.8
Average Phunque Dry Bulk Specific Average T 84 Dry Bulk Specific
Gravity, Sd = 2.646 Gravity, Sd = 2.601
Average Phunque Saturated Bulk T 84 Saturated Bulk Specific
Specific Gravity, Ss = 2.658 Average Gravity, Ss = 2.623
Average Phunque Apparent Dry Average T 84 Apparent Dry Specific
Specific Gravity, Sa =2.679 Gravity, Sa =2.656

TS-1c TP 77-8 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.
 Calculating the CF for each property:
CFabsorption = 0.8/0.5 = 1.6
CFSd
= 2.601/2.646 = 0.983
CFSs
= 2.623/2.658 = 0.987
CFSa
= 2.656/2.679 = 0.991

1
This provisional method of test was adopted and first published in 2009.

TS-1c TP 77-9 AASHTO

© 2013 by the American Association of State Highway and Transportation Officials.
All rights reserved. Duplication is a violation of applicable law.