UFC 3-250-03
15 May 2001
Table 2-7 (Concluded)
Section 2. Procedure for Determining Acceptability of Mix
Criteria
Test Property
Type of Mix
50 Blows
75 Blows
Marshall stability
Hot-Mix Asphalt surface course
500 pounds or
1,800 pounds
higher
or higher
Hot-Mix Asphalt intermediate course
500 pounds or
1,800 pounds
higher
or higher
______a
Sand asphalt
500 pounds or
higher
Unit weight
--
Not used
Not used
Flow
Hot-Mix Asphalt surface course
20 (0.01 inch)
16 (0.01 inch)
or less
or less
Hot-Mix Asphalt intermediate course
20 (0.01 inch)
16 (0.01 inch
or less
or less
______a
Sand asphalt
20 (0.01 inch)
or less
Percentb
Hot-Mix Asphalt surface course
3-5 percent
3-5 percent
voids total mix
Hot-Mix Asphalt intermediate course
3-5 percent
3-5 percent
______a
Sand asphalt
5-7 percent
Percentb
Hot-Mix Asphalt surface course
75-85 percent
70-80 percent
voids filled with
Hot-Mix Asphalt intermediate course
75-85 percent
70-80 percent
asphalt
______a
Sand asphalt
65-75 percent
a
Sand asphalt will not be used in designing pavements for traffic with tire pressures in excess of 690
kPa (100 psi).
b
The theoretical maximum specific gravity can be determined either with the apparent specific gravity
as determined in ASTM C-127 and C-128 or by the use of ASTM D 2041. ASTM D 2041 will be used
for absorptive aggregate.
shown in table 2-8, the optimum asphalt content (average) for the example provided is computed as
4.6 percent. Table 2-9 shows the criteria for acceptability of the mix for a 75-blow compactive effort at
the optimum bitumen content of 4.6 percent.
(3) Determination of optimum bitumen content when using the Gyratory Testing Machine
method.
(a) The criteria for selecting the optimum bitumen content when using the GTM method of
compaction are the same as used for the Marshall method and are as follows:
[1] Gyratory compaction at 690 kPa (100 psi), 1-degree, 30 revolutions shall use the
mix design criteria contained in Sections 1 and 2 of table 2-7 for the 50-blow mix. Additionally, the mix
shall have a gyratory stability index (GSI) equal to or less than 1.
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