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Construction Academy 2014

Construction Academy 2014. Florida Department of. TRANSPORTATION. Tanya Nash State Materials Office. Topics. Asphalt 101 Asphalt Contractor Quality Control Process Miscellaneous Information, Specification Changes, and Research. Asphalt 101. Ground Tire Rubber. Styrene-Butadiene-Styrene

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Construction Academy 2014

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  1. Construction Academy 2014 Florida Department of TRANSPORTATION Tanya Nash State Materials Office

  2. Topics • Asphalt 101 • Asphalt Contractor Quality Control Process • Miscellaneous Information, Specification Changes, and Research

  3. Asphalt 101 Ground Tire Rubber Styrene-Butadiene-Styrene (SBS)

  4. What is an Asphalt Mix? Emission control system Storage silo & load out • Blend of: • Asphalt binder (6%) • Aggregate (94%) • Method of Design • Hubbard Field (…1970’s) • Marshall (1970’s-1998) • Superpave(1998…) • Produced through an asphalt plant Liquidasphalt storage tank Control room Drum Dryer/Mixer RAP/RAS stockpiles RAP/RAS bin Aggregate stockpiles

  5. SUPERPAVE • SHRP (Strategic Highway Research Program): A $150 million research effort over a 5-year period approved by Congress; • Started in 1987 • $50 million spent on asphalt research; • Superpave “System” Delivered in 1993 • Final Product: Superpave (SUperiorPERforming asphalt PAVEments). • Developed to design asphalt pavements that will perform better under the extremes of temperature and loading.

  6. Why did FDOT adopt Superpave? • Existing Pavement Distresses • Rutting • Cracking (fatigue and low temperature cracking) • Forecast for the Future • Greater traffic • More trucks • Super Singles/Wide Based Tires

  7. SuperpaveMix Design Low Temperature cracking

  8. Materials Asphalt Binders Aggregate Stability, Constructability, and moisture resistance Consensus properties (fine aggregate angularity, flat and elongated particles, and clay content) Source properties (toughness, soundness, and deleterious materials) • “Binds” the aggregate together • Provides… • the “glue” • lubrication for compaction • Durability (resistance to cracking) • The most expensive part of an asphalt mix

  9. FDOT Asphalt Binder Price Index (PG 67-22)

  10. Where Does Asphalt Come From? Crude Oil

  11. How Does Crude Get Here? Pipe Ship

  12. Oil Refinery

  13. Fractional Distillation

  14. Crude Oil Distillation (Typical)

  15. Superpave Asphalt Binders • Grading system based on climate PG 67-22 Average 7-day max pavement design temp Performance Grade Min pavement design temp

  16. Examples of PG Grading System • Florida: PG 67-22 (153°F to -8°F) • AC -30 / 60 Pen • Actually PG 67-10 • Minnesota: PG 58-34 (136°F to -29°F) • Arizona: PG 70-10 (158°F to 14°F)

  17. Typical Asphalt Binders The bituminous material specification requirements are outlined in Section 916.

  18. Modified Asphalt Binders (916) • PG 76-22 (PMA) • PG 67-22 base asphalt • Polymer Modified Asphalt (SB or SBS Polymer • PG 76-22 (ARB) • PG 67-22 base asphalt • Minimum 7% ground tire rubber (GTR) • Polymer modification optional • PG 82-22 (PMA) • PG 67-22 base asphalt • Polymer Modified Asphalt (SB or SBS Polymer)

  19. Average Cost per Ton of Asphalt Mix

  20. Typical Asphalt Pavement Structure 1” Friction Course 4” Structural Course 8” Base (Limerock or Asphalt) 12” Stabilized Subgrade

  21. Florida Asphalt Mixtures • Superpave Asphalt Concrete (334) • Structural asphalt mixtures • SP-9.5, SP-12.5, SP-19.0 • Asphalt Concrete Friction Courses (337) • FC-9.5, FC-12.5, FC-5 (OGFC) • Superpave Asphalt Base (234) • B-12.5 • Asphalt Treated Permeable Base (ATPB) (287) • Used under PCC pavements

  22. Superpave – Structural (334) • Purpose: Load carrying portion of pavement • Superpave Mix Design • Three mixes based on maximum aggregate sizes • 9.5 mm (SP-9.5) • 12.5 mm (SP-12.5) • 19.0 mm (SP-19.0) • Five Traffic Levels (A-E) • Based on 18,000 lb. Equivalent Single Axle Loads (ESAL’s) • Low traffic = A, High traffic = E • Concept: Put the right mix on the right road • Higher traffic level is not necessarily better

  23. 15,000 lb 0.48 ESAL 6,000 lb 0.01 ESAL 0.49 ESALs = + 34,000 lb 1.10 34,000 lb 1.10 12,000lb 0.20 = + + ESAL Examples 2.40 ESALs

  24. Mix Design Traffic Levels ESALS come from planning Traffic Levels are found in the Contract

  25. A<300,000 ESAL’s B300,000 to 3,000,000 ESAL’s E>30,000,000 ESAL’s C3,000,000 to 10,000,000 ESAL’s D10,000,000 to 30,000,000 ESAL’s

  26. Traffic Distribution for State Roads

  27. Dense Graded Friction Courses (337 / 334) • Good microtexture • Function of the aggregate • Superpave mixes: • FC-9.5 • FC-12.5 • 100% Oolite or 60% Granite • If granite, then can contain 20% RAP, otherwise no RAP • PG 76-22(ARB) or PG 76-22(PMA) depending on traffic level

  28. Open-Graded Friction Courses (337) • Required on high speed multi-lane facilities • Design Speed ≥ 50 mph • Good macrotexture • Minimize hydroplaning • 100% friction approved aggregate (No RAP) • PG 76-22(ARB) or PG 76-22(PMA) • Stabilizing fibers (more asphalt, less draindown) • Granite aggregate requires hydrated lime

  29. FC-5 Nassau County

  30. FC-12.5 Microtexture FC-5 Macrotexture

  31. Superpave Asphalt Base (234) • 12.5 mm Superpave Mix • Traffic Level B • Paid by the square yard (285 – Optional Base)

  32. Questions/Comments?

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