Transcript Western Canada – John Berti (Husky)

CUPGA 2008
Western Canada
Perspective on
State – of - the Canadian Technology
Challenges and Solutions
John Berti, P. Eng.
[email protected]
Western Canada (WCAN)

Conservative approach to the adoption of the
Superpave system wrt to asphalt binder
specifications and mixture design and analysis
system
– Marshall method is still the preferred system of choice
including traditional pen/viscosity graded binders

Dense fine graded mixtures are most widely
specified
– Minimal percentages of RAP are allowed in most mixes

Very little use of SMA’s for high performance
pavements
Superpave Performance Grade
Binders

“Straight run” asphalts
– WCAN Continues to Use Penetration grades
 (based
on CGSB Pen-Viscosity system)
– PG grades are never or rarely specified
 Small
amounts of PG58-31
Superpave Performance Grade
Binders

Modified Asphalts – (PG = modified)
– Almost all modified demand uses PG specs
– Approx. 7 different grades (from PG76-28 to
PG58-37)
– more commonly used in high service
applications (traffic intersections and slow /
high truck volume applications, new
construction)
– Alberta biggest user, Sask/Man lowest
– No “PG plus” specs but AASHTO M320 Table 2
is occasionally specified
– Alternative bids with life cycle cost adjusts
sometimes used (ie 150/200A or PG 58-34)
Superpave Performance Grade
Binders
 Usage
of PG grades has been
increasing slightly
– Approx 6% of paving asphalts in
Western Canada are specified using PG
specifications
– P3’s are a big factor – contractors
making the decision
Superpave Performance Grade
Binders
 Issues
& Challenges
– Concerns about allowing lower
performing grades
– Concerns about available grade
selection
 Future
changes
– No switching to PG for straight runs in
near term
– BC – increased use of PG 70-22
Superpave Mixes
Used occasionally in BC (Vancouver area)
(improved rut resistance) but minimal
usage in other WCAN provinces
 In the past many Alberta highway projects
used Superpave mix specifications but
usage today has dropped
 Overall estimate less than 10% of Western
Canada mixes are using Superpave mix
specifications.

Superpave Mixes
 Issues
& Challenges
– High aggregate costs and greater pit
depletion
– AB - Concerns about poorer
performance especially with coarser
mixes
 No
big changes expected in the near
term
Stone Mastic Asphalts
 City
of Edmonton has had extensive
experience and use as a regular part
of their program. Usage is expected
to increase slightly.
 Other jurisdictions (Alberta and BC)
have done some SMA trials or
projects and others (Sask/Man.)
have not.
Stone Mastic Asphalts

Issues & Challenges
– Edm - Availability of zero grind (mineral filler)
– High Quality aggregates expensive to import,
mix design, AC drain down, getting good lay
down

Future changes
– Other than Edm. usage of SMA is expected to
stay about the same
– Edm. using cement to replace zero grind
– Edm. looking at smaller max. size aggregate
Other Activities

Warm mix
– Many jurisdictions are doing warm mix trials and a
number of different technologies have been used

Rubber Crumb
– Used extensively throughout Alberta over last 5 years
but a number of agency’s have expressed performance
concerns
– Usage in Alberta in future is questionable
– Trials have been done in BC and Sask as well.

Other emerging technologies over the last 5
years include:
– Ultra thin lift overlays, foamed asphalt stabilized base
course, recycled asphalt shingles
Thank You !