Section 4137.  Asphalt Binder

 

4137.01     general requirements.

 

A.    Meet the requirements for the type and grade specified in the contract documents and comply with the Combined States Binder Group.

 

B.    Determine performance grade according to AASHTO R 29.

 

C.    Do not add acids to modify asphalt binders. Polyphosphoric Acid may be used as a co-modifier up to 0.4% by weight of binder. The Engineer may verify with laboratory testing.

 

D.    For asphalt binder grades with a temperature spread of 92° or greater1, meet the requirements of the Combined State Binder Group as follows: Except for Standard Traffic grades, meet CSBG requirements for Minimum Percent Recovery when tested per AASHTO T 350 at the high temperature identified by the PG grade.

 

Table 4137.01-1: PG+ Requirements

 

AASHTO R 29

Grade

AASHTO T 350

Minimum Percent Recovery (R3.2)

DSR Phase Angle; degrees (original binder)

Test Temperature2

58°C

64°C

58-34P

30

25

77

64-28P

30

25

77

64-34P

55

45

75

70-22P

55

45

77

70-28P

55

45

75

70-34P

75

75

73

76-28P

75

75

73

76-34P

75

75

73

82-22P

75

75

73

1      Temperature spread is determined by subtracting low temperature from high temperature; for example PG 64-28: 64 - (-28) = 92.

2      See Figure 4137.01-01 for test temperatures.

 

Figure 4137.01-01: AASHTO T 350 Test Temperature by County (°C)

Delete this figure.

 

E.    Waive stress sensitivity limits (Jnr Diff) for AASHTO M 332 when Jnr at 3.2 kPa is below 0.5 kPa-1.