UFC 3-250-03
15 May 2001
(2) The required percentage of emulsion can be calculated by dividing the total asphalt required
for the aggregate by the percentage of asphalt residue in the emulsion. A sample calculation for
determining the asphalt content is presented in paragraph SAMPLE CALCULATION OF ASPHALT
REQUIREMENTS FOR A SLURRY SEAL AGGREGATE.
C-3. CONE TEST.
a. The cone test is used to determine the amount of water required to form a workable mixture as
described in ASTM D 3910. This test uses the sand absorption cone described in ASTM C 128. The
cone is placed over a baseplate. The baseplate has concentric circles inscribed in diameters that are
equal to and larger than the large end of the cone. The radius of each circle increases in 12.7 millimeter
(1/2-inch) increments. The cone is loosely filled with a slurry mixture, struck off, and then removed to
allow the slurry mixture to "flow" over the baseplate. A mixture with a flow of 25.4 millimeters(1 inch) is
considered to contain the right amount of water for field workability. Mixtures which will not flow
25.4 millimeters (1 inch) require additional water to obtain the desired flow. If the flow cannot be
obtained without segregation of the mixture, the addition of 0.5 to 4 percent portland cement or hydrated
lime may help to reduce the segregation. Flows greater than 25.4 millimeters (1 inch) indicate excess
water or segregation.
b. If portland cement or hydrated lime is added to reduce segregation and its addition has not been
included in the design gradation, the total bitumen content of the mixture should be corrected to include
the effects of the portland cement or hydrated lime. As a rule, the asphalt content should be increased
by 0.6 percent for every percent of additional portland cement or hydrated lime added to the mixture.
C-4. SAMPLE CALCULATION OF ASPHALT REQUIREMENTS FOR A SLURRY SEAL AGGREGATE.
a. The ASG equals 2.96, and the aggregate gradation includes 2 percent portland cement.
Surface Area Factor
Surface Area
square meters per
square meters per
Percent
kilogram (feet per
kilogram (feet per
Sieve Size
Passing
pound) of Aggregate
pound) of Aggregate
9.5 mm (3/8 inch)
100
0.00409 (0.02)
0.409 (2.00)
4.75 mm (No. 4)
99.5
0.00409 (0.02)
0.407 (1.99)
2.36 mm (No. 8)
95.6
0.00819 (0.04)
0.783 (3.82)
1.18 mm (No. 16)
77.8
0.01639 (0.08)
1.275 (6.22)
600 Fm (No. 30)
52.0
0.02867 (0.14)
1.491 (7.28)
300 Fm (No. 50)
24.5
0.06144 (0.30)
1.505 (7.35)
150 Fm (No. 100)
10.7
0.12289 (0.60)
1.315 (6.42)
75 Fm (No. 200
6.4
0.32771 (1.60)
2.097 (10.24)
Total SA
9.282 (45.32)
Corrected SA (CSA) = SA x 2.65/2.96 = 8.310 square meters per kilogram (40.57 square feet per pound)
of aggregate.
C-3