Summary of Rubber Modified Asphalt Product Specifications around ...

4.2 Material Property Testing of Terminal Blends
For Ontario, the specification requires terminal blend asphalt cement to meet the Type III asphalt
rubber binder according to ASTM D6114 as well as PGAC grade specified.
In California, terminal blend asphalt cement shown in Table 3 is comparable with polymer
modified asphalts. It basically requires the Superpave performance grade specified with some
modifications highlighted in Table 3. Compared with conventional asphalt cements, the
solubility requirement is reduced from 99% to 97.5% for terminal blends with an increase in the
requirement on phase angle at the high temperature and percent recovery from elastic recovery
testing results.
Since terminal blends are similar to polymer modified asphalt, they can be used in any hot mix or
surface treatment application where polymer modified asphalts are used.
5.0 Asphalt Rubber Field Blend Mix Specifications
Asphalt rubber field blends have high viscosity and are more effective when used with gap-
graded or open- graded mixes. In 2011, Ontario built several pilot projects using the asphalt
rubber with gap- graded hot mix asphalt (Tabib et. al. 2012). The following sections present a
comparison of specifications for using asphalt rubber field blend with gap - or open – graded
mixes from various agencies.
5.1 Rubberized Hot Mix Asphalt Gap-Graded
Rubber Modified Asphalt gap-graded mixes consist of mixing gap-graded aggregate and field
blended rubberized asphalt cement and then spreading and compacting the mix to satisfy an
agency’s specification. Most agencies have a similar requirement in their specifications. The
following shows some differences among agencies.
5.1.1 Mix Design Aspect
Not all agencies surveyed used gap-graded asphalt rubber mix. As shown in Table 4, the binder
content of Ontario mix design is on the lower side of that used by other agencies. For California,
the asphalt cement content should not be less than 7% or higher than 9%. In California, the
Contractor provides the Engineer a Material Safety Data Sheet (MSDS) for each of the
constituent components of the asphalt-rubber binder, for the completed mixture of asphaltrubber
binder and for the Type G rubberized asphalt concrete. This should be done in Ontario as
well to make sure there are no deleterious particles in the asphalt cement. The warm mix
technologies may be able to help Ontario with cold temperature paving.
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