UFC 3-250-03
15 May 2001
roads and other pavements. A design index is required for roads and other pavements; it is an index of
the severity of traffic estimate and is defined in TM 5-822-5/AFM 88-7, Chap. 2. Temperature at a
5 centimeter (2-inch) depth of pavement can be estimated from a DFI for a given project location or site
as shown in figure 2-4. This "minimum anticipated pavement temperature" and minimum PVN criteria of
table 2-4 can be used with figure 2-3 to select an asphalt cement. An asphalt with given penetration and
viscosity can be checked for satisfying PVN criteria of table 2-4 by plotting in figure 2-3. If this
penetration and viscosity point falls on or above the minimum PVN value and to the right of the minimum
anticipated pavement temperature, it is estimated that low temperature contraction cracking of the
asphalt concrete layer will be prevented. If it plots to the left of the anticipated pavement temperature,
the pavement will likely crack at low temperature. PVN values should be calculated for more accurate
results.
Table 2-4
Minimum PVN Selection Criteria for Asphalt Cements in Cold Region Use
Road and Other Pavement by Design Index
#4
Cold Region
Airfields
>4
Moderate cold
- 0.5
- 0.5
- 0.5
(DFI # 1,667 degree-days1)
Severe cold
- 0.2
- 0.5
- 0.2
(DFI > 1,667 degree-days1)
1
Degree-Celsius-days (3,000 degree-Fahrenheit-days).
(2) Examples of asphalt cement selection in the three regions.
(a) Asphalt cement selection in a hot region. A parking lot is to be built in a region that
has a pavement temperature index of 54.4, cumulative EC (98, cumulative EF). An asphalt supplier can
provide asphalt cements that meet the requirements in table 2 from ASTM D 3381. Viscosity and
penetration data for the asphalt cements are given below.
AC-10
AC-20
AC-40
Viscosity, 60EC (140EF), P
872
2,200
4,104
135EC (275EF), cSt
298
435
605
Penetration, 25EC (77EF), 0.1 mm
123
70
46
From table 2-3, an asphalt cement that has a penetration of approximately 60 to 70 should be selected.
The AC-20 asphalt cement should be selected for this pavement.
(b) Asphalt cement selection in a warm region.
[1] Asphalt cement (D 3381) original asphalt cement. A street is to be constructed in
a region that has a pavement temperature index of 23.3, cumulative EC (42, cumulative EF). An asphalt
supplier can provide asphalt cements that meet the requirements in table 2 from ASTM D 3381.
Viscosity and penetration data for the asphalt cements are given below.
2-9
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