1. Specification Summary Where weve Been & Where we are Now (A Review of Past & Present Specifications) By: John Garrity Dave Holt, and Ron Bumann

2. Bituminous Specification Timeline Specification 2331(Pre 1988) Specification 2340(1988) Specification 2340 Modified(1997) Specification 2350(1998) Specification 2360(1998) Combined 2350/2360(2003)

3. 2331 MnDOT Standard Specification Before 1988. Agency Designed Mixes for Contractor. Process Control and Acceptance by Agency: Asphalt Spotchecks Aggregate Gradations Contractor Role To Produce and Place Mix

4. Specification 2340 Implemented in 1988 as a Quality Management Specification. Address problems associated with rutting and flushing and raveling. Contractor Involvement –Mix Design –Process Control Testing (QC) Mixture Acceptance –Air voids used as primary acceptance criteria

5. Specification 2340 Modified Implemented 1997 Enhancement to 2340 New Mixture Quality Measures –Voids in Mineral Aggregate (VMA) –Moisture Susceptibility (TSR)

6. Specification 2350 Implemented in 1998 as replacement for 2331 and 2340 (Marshall Design). Complete re-write of 2331 and 2340. Changed mixture designations Included VMA, TSR, F/A Increased Density Requirements Included Ride Requirement Removed methodology of 2331 and 2340 Included Incentives/Disincentives. Move toward end result specification. In 1998, required on all MnDOT projects with traffic < 3 million ESALs.

7. Specification 2360 Implemented in 1998 as Superpave specification and a companion specification to 2350. Same requirements as 2350 including additional aggregate requirements. –Included Incentives/Disincentives. –Move toward end result specification. In 1998, required on all MnDOT projects with traffic > 3 million ESALs.

8. 2360 Combined 2360/2350 (Gyratory/Marshall Design) Specification Implemented in 2003 as a new stand-alone specification. Includes both Marshall and Gyratory (Superpave) design. Current MnDOT specification selection criteria: –Gyratory Design All new construction and mid and long life overlays. –Marshall Design Short life overlays (<5 years) and/or small quantities (<5,000 tons).

9. Responsibility Levels Through Specification Evolution 2331234023502360 Mix DesignAgencyContractor Plant Prod/ControlAgency Contractor Field CompactionAgencyAgncy/ Cont. Contractor (Density)

10. Specification Evolution is a result of... Agency & Industry Initiative –Asphalt Pavement Performance Steering Committee MnDOT, FHWA, Industry, and Local Government –Specification Technical Working Group