Deploying Superpave

1
Deploying Superpave

• A Last Look from the TRB Superpave Committee
• AASHTO SCOH May 6, 2005

2
A Quick History

• SHRP delivers Superpave in mid-93
• FHWA begins implementation 1993
• First state DOT projects 1996
• TEA-21eliminates funding 1998
• AASHTO funds via NCHRP 1999
• TRB Superpave Committee 1999
• Superpave 2005 Strategic Plan 1999
• Where are we now? 2005

3
What is Superpave?

• Asphalt Binder Specs related to traffic and
  climate AASHTO M-320-03
• Mix design procedures that better simulate
  reality AASHTO R-35-04
• Aggregate Specs targeting stability, durability,
  and quality control
• Emphasis on volumetric mix properties permitting
  better construction control

4
Superpave Binder
2005 Survey of AASHTO HSCOM
5
Superpave Mix
Generally used
2005 Survey of AASHTO HSCOM
6
Has It Been Worth It?

• Economic Benefits of SHRP Research
• (Little et al., 1997, Texas Transportation Inst.)
• If binder specs implemented over 10 years,
  national annual discounted agency savings in 10th
  year
• 482 Million

7
Scant Benefit/Cost Data

• Only 13 states have gathered data
• Only 8 have analyzed it.
• Others plan to gather and analyze data.
• 4 provinces and 1 turnpike authority have
  gathered data.
• Committee will recommend a comprehensive look at
  these data

8
Benefit Indicators

• Washington State
• 3 cost, 12 to 20 longer performance
• New York City
• No cost increase, 1 to 3 years in extra
  performance
• Ontario
• -2 cost, 1 to 2 years increase in performance
• SPS-9
• Reflective cracking retarded 3 to 4 years

• Arkansas
• Considerably fewer problems
• Connecticut
• Evidence of reduced rutting
• Louisiana
• Less rutting
• Pennsylvania
• Rutting problem has been solved.

9
More Indicators

• City of Calgary
• Better performance at same cost
• City of Ottawa
• Marked reduction in cracking
• Minnesota
• Better ride, higher pavement sufficiency,
  slightly less cost

• Utah
• 3 years life increase
• 10 LCC savings
• Utah DOT Region 2
• Crack sealing cost down 70
• Patching costs down 20

10
Coming Soon

• Simple Performance Test and equipment
• New mix design guide for hot-mix asphalt
• Linked to new pavement design guide
• Improved Asphalt Stripping Test
• Performance-related tests for modifiers

11
Sources of Success

• Constancy of Purpose, Consistency of Plan
• True Government/Industry Partnership
• Continuous dialogue
• Broad industry participation in advisory groups
• Superpave Support Team
• Innovative Approaches to Deploying Innovation.

12
Superpave 2005

• Questions?

13
A Cause for Concern?

• The Rise of Superpave Plus Specifications
• Additional Specs or Tests
• What are the Pluses?
• Prescriptions, Exclusions, Other Tests
• How Prevalent Are Plus Specs?
• 21 states in 2002, 34 states in 2005
• Warrants Continued Monitoring by AASHTO