Asphalt Mixture Testing


 Theoretical maximum specific gravity and density of
paving mixture : ASTM D2041.
 Quantitative Extraction of Bitumen From Bituminous
Paving Mixtures: ASTM D2172.
 Preparation of Bituminous Specimens Using
Marshall Apparatus: ASTM D6926.
 Bulk Specific Gravity and Density of Non Absorptive
Compacted Bituminous Mixtures :ASTM D2726
 Marshall Stability and Flow of Bituminous Mixtures:
ASTM D6927.
Outlines


Theoretical maximum
specific gravity and density
of paving mixture:
ASTM D2041.


 Vacuum Flask for Weighing in Air, a thick-walled
volumetric glass flask with a capacity of
approximately 4000 mL, fitted with a rubber stopper
with a connection for the vacuum line.
 Balance, capable of being read to the nearest 0.1 g.
 Vacuum Pump or Water Aspirator, capable of
evacuating air from the vacuum container to a
residual pressure of 4.0 kPa.
 Mechanical Agitation Device, capable of applying a
gentle but consistent agitation of the sample
Apparatus


 The size of sample shall be as follows:
Sampling
Nominal Maximum
Aggregate Size, mm [in.]
Minimum Sample Size, g
37.5 [1 ½] or greater 5000
19 to 25 [3/4 to 1] 2500
12.5 [1/2] or smaller 1500


 Calibrate the volumetric flask by accurately determining
the mass of the flask filled with water at a temperature of
25 +- 1°C.
 Once the sample is dry and while it is still warm, separate
the particles of the sample of paving mixture by hand,
Cool the sample to room temperature. If separated
particles adhere to each other once the sample has been
cooled to room temperature, gently separate the particles
of the fine aggregate portion so that they are not larger
than about 6 mm. Place the sample directly into the tared
volumetric flask. Weigh the container with the sample
and designate the net mass (mass of sample only) .
Procedure


 Add sufficient water at a temperature of approximately
25°C to cover the sample completely. Place the cover on
the container.
 Place the container with the sample and water on a
mechanical agitation device. Start the agitation and
immediately begin to remove air trapped in the sample
by gradually increasing the vacuum pressure until the
residual pressure manometer reads 3.7 +- 0.3 kPa.
 The vacuum should be achieved within 2 min. Once the
vacuum is achieved, continue the vacuum and agitation
for 15 +- 2 min.
 Gradually release the vacuum pressure.


 Slowly fill the flask with water taking care not to
introduce air into the sample. Place the flask in a water
bath for 10 +- 1 min to stabilize the temperature without
submerging the top of the flask. Measure and record the
temperature of the water in the flask. Remove the
thermometer and completely fill the flask using a cover
plate, taking care not to entrap air beneath the cover
plate.
 The cover plate shall be the same one used during the
calibration of the flask. Wipe any moisture from the
exterior of the container and cover plate. Determine the
mass of the flask, plate, and its contents completely
filled with water.


𝐺𝑚𝑚 =
𝐴
𝐴+𝐷−𝐸
Where,
A: mass of dry sample in air
D: mass of cover plate and flask filled with water
at25°C
E: mass of flask, cover plate, sample, and water


Quantitative Extraction of
Bitumen From Bituminous
Paving Mixtures: ASTM
D2172.

 Oven, capable of maintaining the temperature at 110+-
5°C .
 Balance, with an accuracy of at least 0.1g.
 Extraction Apparatus, consisting of a bowl approximating
that shown in Fig. 1 and an apparatus in which the bowl
may be revolved at controlled variable speeds up to 3600
r/min.
Apparatus


Procedure Method A
Figure No. 1


 warm to 110 +- 5°C only until it can be handled or mixed. Split or
quarter the material until the mass of material required for test is
obtained.
 The size of the test sample
Sampling


 Place the test specimen into the bowl.
 Cover the test portion in the bowl with trichloroethylene,
normal Propyl Bromide, or methylene chloride and allow
sufficient time for the solvent to disintegrate the test
portion (not over 1 h).
 Place the bowl containing the test portion and the solvent
in the extraction apparatus.
 Dry and determine the mass of the filter ring and fit it
around the edge of the bowl. Clamp the cover on the bowl
tightly and place a beaker under the drain to collect the
extract.
Procedure


 Start the centrifuge revolving slowly and gradually
increase the speed to a maximum of 3600 r/min or until
solvent ceases to flow from the drain.
 Allow the machine to stop, add 200 mL of
trichloroethylene, repeat the procedure. Use sufficient
200-mL solvent additions (not less than three) so that the
extract is not darker than a light straw color. Collect the
extract and the washings in a suitable graduate.


 Remove the filter from the bowl and dry it to constant
mass in an oven at 110 +- 5°C. Carefully remove all the
contents of the bowl into a metal pan and dry to
constant mass in an oven or on a hot plate at 110 +-5°C .
 The mass of the extracted aggregate, W 3, is equal to the
mass of the aggregate in the pan plus the increase in
mass of the filter rings.


 Determine the amount of mineral matter in the extract
using Ashing Method:
 Record the volume of the total extract in the graduate.
Determine the mass of an ignition dish. Agitate the
extract thoroughly and immediately measure
approximately 100 mL into the ignition dish.
 Evaporate to dryness. Ash residue at a heat of 500 to
600°C , cool, and add 5 mL of saturated ammonium
carbonate solution per gram of ash. Digest at room
temperature for 1 h. Dry in an oven at 100°C to constant
mass, cool in a desiccator, and determine the mass.


𝑊4 = 𝐺
𝑉1
𝑉1−𝑉2
Where;
 W4:the mass of mineral matter in the total volume of extract.
 G: ash in aliquot, g.
 total volume,
 volume after removing aliquot


𝐵𝑖𝑡𝑢𝑚𝑒𝑛 𝐶𝑜𝑛𝑡𝑒𝑛𝑡% =
𝑤1 −(𝑤3+𝑤4)
(𝑤1)
X100
 Where;
 W 1 = mass of test portion,
 W3 = mass of the extracted mineral aggregate, and
 W4 = mass of the mineral matter in the extract.


Preparation of Bituminous
Specimens Using Marshall
Apparatus: ASTM D6926.


 This practice covers preparation and compaction of
102 mm (4 in.) diameter by nominal 64 mm (2.5 in.)
high cylindrical bituminous paving mixture
specimens.
Scope


 Specimen Extractor—The specimen extractor shall
have a steel disk that will enter the mold without
binding and not be less than 3.95 in. (100 mm) in
diameter and 1⁄2 in. (12.5 mm) thick.
 Compaction Hammers:
- Weight :10 +- 0.02 lb
-free fall distance: 18 +- 0.06 in
Apparatus


 Materials shall be warmed in covered containers in
an oven at a temperature between (120°C) and
(135°C). In preparation for heating to compaction
temperature the material should be warmed and
worked until a loose mixture condition is obtained.
Test Specimens


 Compaction of Specimens:
 Thoroughly clean the specimen mold assembly and the
face of the compaction hammer and heat them a
temperature between 90 and 150°C. Place a piece of
nonabsorbent paper, cut to size, in the bottom of the
mold before the mixture is introduced. Place the mixture
in the mold, spade the mixture vigorously with a heated
spatula or trowel 15 times around the perimeter and 10
times over the interior.


 Place another piece of nonabsorbent paper cut to fit on
top of the mix. Temperature of the mixture immediately
prior to compaction shall be within the limits of the
compaction temperature.
 Place the mold assembly on the compaction pedestal in
the mold holder and apply the required number of
blows with the specified compaction hammer.
 Number of blows = Typically 35, 50 or 75 on each side
depending upon anticipated traffic loading.


 Remove the base plate and collar and reverse and
reassemble the mold. Apply the same number of
compaction blows to the face of the reversed
specimen. After compaction, remove the collar and
base plate. Allow the specimen to cool sufficiently to
prevent damage and extract the specimen from the
mold.


Bulk Specific Gravity and
Density of Non Absorptive
Compacted Bituminous
Mixtures :ASTM D2726


 Specimens shall be free of foreign materials such as
seal coat, tack coat, foundation material, soil, paper,
or foil. When any of these materials are visually
evident, they shall be removed by sawing. Wire
brushing to remove paper, soil, and foil is acceptable
if all traces of the materials are eliminated.
Sampling


 Mass of Specimen in Water—Completely submerge the
specimen in the water bath at 25 +- 1°C for 3 to 5 min
then determine the mass by weighing in water. If the
temperature of the specimen differs from the
temperature of the water bath by more than 2°C , the
specimen shall be immersed in the water bath for 10
to 15 min, instead of 3 to 5 min
Procedure


 Mass of Saturated Surface-Dry Specimen in Air— Surface
dry the specimen by blotting quickly with a damp cloth
towel and then determine the mass by weighing in air.
Designate this mass as B.
 After determining the mass in water and in a saturated
surface dry condition, thoroughly dry the specimen to a
constant mass at 110 +- 5°C . Allow the specimen to cool
and weigh in air. Designate this mass as A.


𝐺𝑚𝑏 =
𝐴
𝐵−𝐶
 Where;
 A: mass of the dry specimen in air
 B: mass of the saturated surface-dry specimen in air
 C: mass of the specimen in water


Marshall Stability and Flow
of Bituminous Mixtures:
ASTM D6927.


 This test method covers measurement of resistance
to plastic flow of 102 mm (4 in.) cylindrical
specimens of bituminous paving mixture loaded in a
direction perpendicular to the cylindrical axis by
means of the Marshall apparatus.
Scope

 Loading Machine: The loading machine shall be designed to
load at a uniform vertical movement of 50 +- 5 mm/min.
 Flowmeter— is an attached dial gauge measures the specimen’s
plastic flow as a result of the loading.
 Graduations of the flowmeter gage shall be increments of 0.25 mm
(0.01 in.).
 Water Bath—The water bath shall be deep enough to maintain the
water level a minimum of 30 mm above the top of specimens. The
bath shall be thermostatically controlled so as to maintain the
specified test temperature +-1°C at any point in the tank. The tank
shall have a perforated false bottom or be equipped with a shelf for
supporting specimens 50 mm above the bottom of the bath and be
equipped with a mechanical water circulator.
Apparatus


 A minimum of three specimens of a given mixture shall
be tested
 Specimens should be cooled to room temperature after
compaction. Bulk specific gravity of each specimen shall
be determined
 The bulk specific gravities of replicate specimens for
each binder content shall agree within +-0.020 of the
mean as noted in Practice D6926.
 Measure specimen thickness according to Test Method
D3549.
Procedure


 Specimens can be conditioned for testing as soon as they
reach ambient room temperature. Testing shall be
completed within 24 h after compaction.
 Immerse the sample in the water bath at a temperature
60+-1°C for 30.
 Remove a specimen from the water and remove excess
water with a towel and place in the lower segment of the
testing head. Place the upper segment of the testing
head on the specimen, and place the complete assembly
in position in the loading machine.


 The elapsed time from removal of the test specimens
from the water bath to the final load determination shall
not exceed 30 s. Apply load to the specimen by means of
the constant rate of 50 +- 5 mm/min until the dial gage
releases or the load begins to decrease.
 note the micrometer dial reading the instant when the
load decreases.
 Marshall flow is the total sample deformation from the
point where the projected tangent of the linear part of
the curve intersects the x-axis (deformation) to the point
where the curve starts to become horizontal

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