Summary of Rubber Modified Asphalt Product Specifications around ...

Table 4. Mix Design Parameter Comparison from Various Agencies
Agency Mix Design Binder Content
Method and binder type
Ontario, Canada Superpave 6.5% for 12.5
mm;
7.0% for 9.5 mm
by weight of
total mix;
PG58-28
California Hveem mix
design
Arizona Marshall mix
design
Jiangsu, China Marshall mix
design
5.1.2 Construction Considerations
7.0 to 9.0% by
weight of dry
aggregate; PG64-
16
5.5± 1.0% air
void;
Gradation, air
voids, and others
Gap-graded 12.5
mm, 9.5 mm, 4%
design air void;
VMA min is
18%
Gap-graded 12.5
mm, 19 mm;
VMA min is
18%;
Stabilometer
stability value
min 23.
Gap-graded;
VMA min
19.0%; Absorbed
asphalt rubber, 0-
1%.
Gap-graded 13.2
mm; VMA 18-
23%.
Notes
Caltrans will
convert to
Superpave by
2014; Caltrans
allows using
approved warm
mix technologies
to deal with cold
and night paving
issues.
Marshall stability
≥ 8000 N; Flow
number 20-50.
Construction practices and environments are very different between the various agencies.
California, Arizona, and China are very successful with their gap-graded asphalt rubber
pavement. Table 5 shows the requirements used to make a successful asphalt rubber gap-graded
pavement at their environment. There are missing temperature requirements in the Ontario gap-
graded asphalt rubber specification. The information from other agencies may be a good starting
point for Ontario.
12