Civil Engineering Reference
In-Depth Information
9.7
Classification of Asphalt
Several methods are used to characterize asphalt binders, asphalt cutbacks,
and asphalt emulsions.
■
9.7.1
Asphalt Binders
Asphalt binder is produced in several grades or classes. There are four meth-
ods for classifying asphalt binders:
1. performance grading
2. penetration grading
3. viscosity grading
4. viscosity of aged residue grading
Performance Grade Specifications and Selection
Several grades of binder are
available, based on their performance in the field. Names of grades start with
PG (Performance Graded) followed by two numbers representing the maxi-
mum and minimum pavement design temperatures in Celsius. For example,
an asphalt binder PG 52-28 would meet the specification for a design high
pavement temperature up to 52°C (126°F) and a design low temperature
warmer than These temperatures are calculated 20 mm
(0.75 in.) below the pavement surface. The high and low pavement temper-
atures are related to the air temperature as well as other factors. Table 9.2
shows the binder grades in the Performance Grade specifications. PG 76
and 82 are intended to accommodate only slow transient or standing loads,
such as those that occur near intersections or in truck climbing lanes.
The performance-graded asphalt binder specifications are shown in
Table 9.3 (ASTM D6373). The table shows the design criteria of various test
- 28°C
1
- 18°F
2
.
T ABLE 9.2
Binder Grades in the Performance Grade
Specifications
High Temperature
Grades (°C)
Low Temperature Grades (°C)
PG 46
PG 52
PG 58
PG 64
PG 70
PG 76
PG 82
- 34, - 40, - 46
- 10, - 16, - 22, - 28, - 34, - 40, - 46
- 16, - 22, - 28, - 34, - 40
- 10, - 16, - 22, - 28, - 34, - 40
- 10, - 16, - 22, - 28, - 34, - 40
- 10, - 16, - 22, - 28, - 34
- 10, - 16, - 22, - 28, - 34
Search WWH ::
Custom Search