UFC 3-250-03
15 May 2001
Table C-1
Factors Used in Calculating Surface Area of Slurry Seal Aggregate
Surface Area Factors
Square Meters Per
Square Feet per
Sieve Size
Kilogram of Aggregate
Pound of Aggregate
9.5 millimeter (3/8 inch)
0.00409
0.02
4.75 millimeter (No. 4)
0.00409
0.02
2.36 millimeter (No. 8)
0.00819
0.04
1.18 millimeter (No. 16)
0.01639
0.08
600 Fm (No. 30)
0.02867
0.14
300 Fm (No. 50)
0.06144
0.30
150 Fm (No. 100)
0.12289
0.60
75 Fm (No. 200)
0.32771
1.60
(2) If the specific gravity of the asphalt is not known, the asphalt required to coat the aggregate
may be calculated by assuming SGA = 1.0. The error that results from assuming SGA = 1.0 is small and
will not greatly affect the final design requirements.
b. Aggregate absorption. The absorption requirements of the aggregate are determined by using
the Centrifuge Kerosene Equivalent (CKE) described in ASTM D 5148. In this test, 100 grams of minus
4.75 millimeter (No. 4) material is centrifuged in the presence of kerosene for 2 minutes. The amount of
kerosene retained by the aggregate is assumed to approximate the amount of asphalt that the
aggregate will absorb. The kerosene absorbed (KA) by the aggregate is converted to a percentage of
the dry weight of the aggregate.
c. Total asphalt.
(1) The total asphalt requirement is obtained by adding the percent asphalt required for the film
thickness and the percent asphalt required for absorption. All percentages are based on the dry weight
of the aggregate. The total is obtained as follows:
AR ' SAA % KA
(eq E-2)
or
Metric: (CSA t 0.99941 SGA ) % KA
AR '
(eq E-3)
U.S. Customary: (CSA t 0.02047 SGA ) % KA
where
AR = total asphalt required, percent of dry aggregate weight
KA = kerosene absorbed, percent of dry aggregate weight
C-2
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