UFC 3-250-03
15 May 2001
are deposited outside the basket should be added back into the mixture and not counted as draindown.
Alternatively, the test should be rerun.) This test method can be used to determine whether the amount
of draindown measured for a given SMA mixture is within acceptable levels. It also provides an
evaluation of the draindown potential of an SMA mixture produced in the field.
(a) Scope. This test method covers the determination of the amount of draindown in an
uncompacted SMA mixture sample when the sample is held at elevated temperatures comparable to
those encountered during the production, storage, transport, and placement of the mixture.
(b) Summary of Method. A sample of the SMA mixture to be tested is prepared in the
laboratory or obtained from field production. The sample is placed in a wire basket which is positioned
on a pre-weighed paper plate. The sample, basket, and plate are placed in a forced air oven for one
hour at a preselected temperature. At the end of one hour, the basket containing the sample is removed
from the oven along with the paper plate and the paper plate is weighed to determine the amount of
draindown that occurred.
(c) Equipment.
[1] Oven, capable of maintaining the temperature in a range from 120E-175EC (250E-
350EF). The oven should maintain the set temperature to within 2EC ( 3.6EF).
[2] Paper plates of appropriate size. The paper plates used should be of appropriate
durability to withstand the oven temperatures.
[3] Standard cylindrical shaped basket meeting the dimensions shown in figure 2-11.
The basket shall be constructed using standard 6.3 millimeter (0.25 inch) sieve cloth as specified in
ASTM E 11.
[4] Spatulas, trowels, mixer, and bowls as needed.
[5] Balance accurate to 0.1 gram.
(d) Sample preparation. For each mixture tested, the draindown characteristics should be
determined at the anticipated plant production temperature. Duplicate samples should be tested.
[1] Laboratory sample preparation. Dry the aggregate to constant mass and sieve it
into appropriate size fractions as indicated in ASTM D 1559. Determine the anticipated plant production
temperature or select a mixing temperature in accordance with ASTM D 1559. The asphalt cement
supplier's recommendations should be sought when using modified asphalt cement. Weigh into
separate pans for each test sample the amount of each size fraction required to produce completed
SMA mixture samples having a mass of 1200 grams. The aggregate fractions should be combined such
that the resulting aggregate blend has the same gradations as the job mix formula. Place the aggregate
samples in an oven and heat to a temperature not to exceed the mixing temperature established above
by more than approximately 28EC (50EF). Heat the asphalt cement to the established mixing
temperature. Place the heated aggregate in the mixing bowl. When a stabilizer is used it should be
added as directed by the supplier. Some types of stabilizers such as fibers or some polymers must be
added directly to the aggregate prior to mixing with the asphalt cement. Other types must be added
directly to the asphalt cement prior to blending with the aggregate. The aggregates and any other
components should be thoroughly mixed together. Form a crater in the aggregate blend and add the
required amount of asphalt. The amount of asphalt shall be such that the final sample has the same
asphalt content as the job-mix-formula. At this point, the temperature of the aggregate and asphalt
cement shall be within the limits of the mixing temperature. Using a spatula (if mixing by hand) or a
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