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Bituminous Street Re-certification

Bituminous Street Re-certification. Specification Discussion. (2360) PLANT MIXED ASPHALT PAVEMENT Combined 2360/2350 (Gyratory/Marshall Design) Specification. Implemented in 2003 as a new stand-alone specification. Includes both Marshall and Gyratory (Superpave) design.

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Bituminous Street Re-certification

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  1. Bituminous Street Re-certification Specification Discussion

  2. (2360) PLANT MIXED ASPHALT PAVEMENTCombined 2360/2350 (Gyratory/Marshall Design) Specification • Implemented in 2003 as a new stand-alone specification. Includes both Marshall and Gyratory (Superpave) design. • Complete re-write of 2331 and 2340 and a combining of 2350 and 2360. • Changed mixture designations • Included VMA, TSR, F/A • Increased Density Requirements • Included Ride Requirement • Removed methodology of 2331 and 2340 • Includes Incentives/Disincentives.

  3. Over a Decade of Changes • Hot Mix Asphalt Specifications in Minnesota have changed dramatically since 1988. • In 1988, Quality Management Specification 2340 • In 1997, PG Grading System Implemented • In 1998, 2350 (Marshall) and 2360 (Superpave) • In 2003, 2360 Combined Marshall and Superpave Specification.

  4. Why the Changes? • Agency staffing and philosophy changes have put more responsibility with the Contractor (QC/QA). • Agency/Industry partnership • The need for more durable mixtures. • Superpave (Gyratory) • Increased traffic and loadings • Engineered mixtures • Better understanding of HMA design. • New technology.

  5. Pavement Distress in Minnesota

  6. Our Goal

  7. 2360 Combined 2360/2350 (Gyratory/Marshall Design) • Durability Through…. • Improved Material Requirements • Improved Design Requirements • QC/QA • Improved Density Requirements • Improved Smoothness Requirements

  8. Material Requirements • PG Asphalt Selection • Mineral Aggregate -- provides the stone skeleton to support and carry the load. • Aggregate Properties • Los Angeles Rattler • Magnesium Sulfate Soundness • Spall Material • Gradation Requirement • Crushing

  9. Today’s Typical Cold Feed Setup

  10. Design Requirements • Volumetrics • Air Voids (gyratory compactor) • Asphalt Content • VMA • Moisture Susceptibility • TSR • Fines/Effective Asphalt

  11. Quality Control/Quality Assurance • Agency/Industry Partnership • Certified Plant • Production Test Results • Air Voids • Asphalt Content • Gradation • Crushing • VMA

  12. One of the Biggest Differences Between Now and Then…. • Complexity of the Specifications… • Production Control with Old Specification • Acceptance on per test basis • Spotcheck and gradation • Production Control with Current Specification • Acceptance on individual and moving average test results • Volumetrics • Air voids, VMA, Asphalt content • Gradation • Crushing • Density • Ride

  13. Incentive/Disincentive • Density and Ride • Incentive Purpose: • To encourage the contractor to provide workmanship and a final product above and beyond the minimum contract requirements. • Anticipated Direct Benefits of Incentive: • Longer service life • Reduced maintenance costs • Allows the better Contractor to bid in the incentive and possibly end up low bidder. • Incentives must be paid in a timely manner.

  14. Incentive/Disincentive • Historically, penalties haven’t gotten us what we want. Penalties don’t equate to quality. Penalties are difficult to collect. • I/D provision has set the bar higher. Statistically, 1/3 of results will be at 100% pay and 2/3 will be above or below 100% pay.

  15. Incentive Costs* • Density will typically add $0.15/ton of mix • Ride will typically add $0.45/ton of mix * Based on TH data from 1998 - 2003

  16. Before the Project Starts… • Review plans, proposal, and special provisions. • Familiarize yourself with: • Typical sections • Different mixes, widths, thicknesses, etc. • Inspector/Job Superintendent should discuss sequence of operations and agree on a system of communication.

  17. 2360Combined 2360/2350 (Gyratory/Marshall Design) Specification • Includes Marshall and Gyratory design. • Mixture Designation convention: • Ex. For Marshall: • LVWE35030C • Ex. For Gyratory: • SPWEB540F • Pay Item convention: • Ex. 2350.609 Type LV 3 Wearing Course C • Ex. 2360.609 Type SP 12.5 Wearing Course (5,F)

  18. 2360/Superpave Designation Max Size A (SP 9.5mm) -1/2” B (SP 12.5mm) -3/4” C (SP 19.0mm) -1” 2360/Marshall Designation Max Size 4 -1/2” 3 -3/4” 2 -1” 5 -3/8” Gradation Sizes

  19. 2360Combined 2360/2350 (Gyratory/Marshall Design) Specification • Air Void Requirements

  20. (2360) PLANT MIXED ASPHALT PAVEMENTCombined 2360/2350 (Gyratory/Marshall Design) Specification • Section 2360.4 J, JMF Adjustment • Requires the Contractor to start production with all aggregate proportions included on the Mix Design Report unless the aggregate proportion is shown as 0 % (add rock/add sand provision).

  21. (2360) PLANT MIXED ASPHALT PAVEMENTCombined 2360/2350 (Gyratory/Marshall Design) Specification • Shoulder Density Requirement • Specification defaults to Ordinary Compaction when shoulder is 6 feet wide or less. • Specification defaults to Maximum Density when shoulder is wider than 6 feet. • Check Special Provisions for specific Contract requirements.

  22. (2360) PLANT MIXED ASPHALT PAVEMENTCombined 2360/2350 (Gyratory/Marshall Design) Specification • Density Incentive Modification • Incentive for density allowed when the “day’s weighted average production air voids are less than 0.5% from the target air void”. Used to be based on individual air void for that lot.

  23. Random number location and actual coring location

  24. Waiving reduced density provision • Specification defaults to 1% reduced density from minimum required density when: • First lift on PCC • First lift on aggregate base, reclaimed or cold inplace recycled, or first lift on roadway with 7 ton or less spring load restriction. • Incentive payment is excluded on reduced density • Contractor can request reduced density be waived (must be approved by Engineer) • Incentive payment will be made if reduced density waived • First lift reduced density on PCC not allowed • Request and approval must be made after 1st day paving and before 3rd days paving begins. • Incentive/Disincentive payment goes back to include 1st day paving

  25. (2360) PLANT MIXED ASPHALT PAVEMENTCombined 2360/2350 (Gyratory/Marshall Design) Specification • Thickness and Surface Smoothness Requirements. • 1/4” tolerance for surface measured with straightedge laid parallel or at right angle to centerline.

  26. (2360) PLANT MIXED ASPHALT PAVEMENTCombined 2360/2350 (Gyratory/Marshall Design) Specification • Smoothness General • Contractor and Agency must mutually agree on scheduling of smoothness testing so that Agency can be present to observe testing. • Unless otherwise approved, any testing performed without Agency presence can be ordered re-tested.

  27. Bituminous Web Page www.mrr.dot.state.mn.us/pavement/bituminous/bituminous.asp

  28. Web Page Contents • Bituminous Specifications and Highlights • Bituminous Laboratory Procedures, Field Procedures and Lab Manual • Spread Sheets and Other Tools • Design Aids and Miscellaneous Documents • Miscellaneous Forms • People and Phone Numbers

  29. Confusion about the new 2360 ?? • Need Help, Contact: • State-Aid • District Materials • Bituminous Office

  30. Bituminous Office Phone #’s • John Garrity (651)779-5577 • Dan Boerner 779-5582 • Dave Linell 779-5614 • Joseph Thomas 779-5619 • (Trial Mix Lab) 779-5621 • Fax 779-5580

  31. Questions ??

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