UFC 3-250-03
15 May 2001
Table 2-2
Specification References for Asphalt Materials
Bitumen Type
Specification
Asphalt cement (Performance graded asphalt binder)
ASTM D 946, D 3381 (AASHTO MP-1)
Cutback asphalt (slow-curing type)
ASTM D 2026
Cutback asphalt (medium-curing type)
ASTM D 2027
Cutback asphalt (rapid-curing type)
ASTM D 2028
Asphalt, emulsified
ASTM D 977
Asphalt, cationic emulsified
ASTM D 2397
Rubberized tar cement
ASTM D 2993
Tar
ASTM D 490 and D 2993
general, the softest grade of asphalt cement consistent with traffic and climate should be used.
Selecting a grade of asphalt cement should be based on several items. Among the most important are
climate, traffic conditions, economics of asphalt availability, and previous regional experiences. Traffic
conditions and economic considerations will vary from project to project, but environmental conditions
and regional experiences should have some similarity. For example, in warm and hot regions one
should ensure that the mix is stable during the summer months, and in cold regions one should ensure
that the mix is not prone to cracking during winter months. The Departments of the Army and Air Force
have additional requirements for asphalt cements that will perform satisfactorily in very cold climates
such as Alaska, Greenland, and the northern continental United States. These requirements are
discussed in the following subparagraphs.
(1) Asphalt cement selection by temperature region.
(a) Determining temperature region. Table 2-3 gives guidance for selecting an asphalt
cement by temperature region. Climatological data are required to provide input into the selection
method. First, average monthly maximum temperature data are required to compute a pavement
temperature index (PTI), when project locations have average monthly maximum temperatures above
23.9EC (75EF), the PTI is defined as the sum of the monthly increments exceeding 23.9EC (75EF).
Conversely, when no average monthly temperature exceeds 23.9EC (75EF), the PTI is defined as the
difference between the highest average maximum temperature for the warmest month and 23.9EC
(75EF).
Table 2-3
Asphalt Cement Selection Criteria Based on Pavement Temperature Index
Pavement Temperature
Index, Cumulative EC (EF)
Temperature Region
Asphalt Cement Selection Criteria
Less than 16.7 (30)
Cold
Penetration-viscosity method for cold
regions (table 5)
16.7 to 44.4 (30 to 80)
Warm
85 to 100 penetration (original asphalt)
Greater than 44.4 (80)
Hot
60 to 70 penetration (original asphalt)
(b) Example of calculations for pavement temperature index. The method for calculating
the pavement temperature index for two construction sites is given in this example. The average
2-7
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