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Construction Academy 2012 Asphalt Materials

Tanya Nash State Materials Office. Construction Academy 2012 Asphalt Materials. Topics. Asphalt Overview Asphalt CQC (Specs 334 and 337) Miscellaneous Information, Specification Changes, and Research. Asphalt Overview. Typical Asphalt Pavement Structure. 1” Friction Course .

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Construction Academy 2012 Asphalt Materials

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  1. Tanya Nash State Materials Office Construction Academy 2012Asphalt Materials

  2. Topics • Asphalt Overview • Asphalt CQC (Specs 334 and 337) • Miscellaneous Information, Specification Changes, and Research

  3. Asphalt Overview

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

  5. What is an Asphalt Mix? • Blend of: • Asphalt binder (6%) • Aggregate (94%) • Method of Design • Hubbard Field (…1960’s) • Marshall (1960’s – 1998) • Superpave (1998 ….) • Produced through an asphalt plant

  6. Average Cost per Ton of Asphalt Mix

  7. Asphalt Binders • “Binds” the aggregate together. • Provides….. • the “glue.” • lubrication for compaction. • durability (resistance to cracking). • The most expensive part of an asphalt mix.

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

  9. Where does asphalt come from? Crude Oil

  10. How does crude get here? Pipeline Ship

  11. Oil Refinery

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

  13. Examples of PG Grading System • Florida: PG 67-22 (153°F to -8°F) • Old 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)

  14. Typical Asphalt Binders (916) • PG 67-22 – Standard Grade • <20% Reclaimed Asphalt Pavement (RAP) • PG 64-22 • 20 – 29% RAP • Recycling Agent (RA) • ≥ 30% RAP • PG 76-22 • PG 67-22 base asphalt + SB or SBS Polymer • ≤ 20% RAP

  15. Typical Asphalt Binders (916) • Asphalt Rubber Binders • ARB-5 - Dense graded friction course (≤ 20% RAP). • ARB-12 - Open graded friction course (no RAP). • ARB-20 - Asphalt Rubber Membrane Interlayer (ARMI). No Rap allowed.

  16. Typical FL Mix Types • Structural Courses (334) Superpave • SP-9.5, SP-12.5, SP-19.0 • Friction Courses (337) • FC-9.5, FC-12.5, FC-5 (OGFC) • Base Courses (234) • B-12.5 • Other • Asphalt Treated Permeable Base (ATPB) • Used under PCC pavements

  17. Superpave - Structural (334) • Purpose: Load carrying portion of pavement • Superpave Mix Design • Three mixes based on max 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

  18. 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

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

  20. 1% 3% 19% TL-A 40% TL-B TL-C TL-D TL-E 37% Traffic Distribution for State Roads D B C

  21. Gradation Types • Coarse mixes – More coarse aggregate than fine • Higher density requirement • Greater likelihood of being permeable • Placed thicker • Tough workability • Fine mixes – More fine aggregate than coarse • Similar to old FDOT Type S mixes • Shown on the mix design

  22. Fine graded SP-12.5 mix

  23. Coarse graded SP-19.0 mix

  24. Friction Courses (337) • Purpose: Provide a pavement surface with good tire/pavement friction. • Required on all jobs with: • Design Speed ≥35 mph, except rural 2-lane roads with 5-yr projected AADT of ≤3,000. • Use polish resistant aggregate • Oolitic limestone (Dade & Broward Counties) • Granite (Georgia & Canada) • Siliceous Wackestone (Canada) • Shell rock (Palm Beach Co.) • Use asphalt rubber binder (ARB) or PG76-22.

  25. Fine Graded Friction Courses • Good microtexture • Function of the aggregate • Superpave mixes: • FC-9.5 (1” thick) • FC-12.5 (1 ½” thick) • Formerly called FC-6 • 100% oolite or 60% granite • If granite, then can contain 20% RAP, otherwise no RAP. • ARB-5 or PG 76-22 depending on traffic level.

  26. Open-Graded Friction Courses • Required on high speed multi-lane facilities. • Design Speed ≥ 50 mph • Good macrotexture. • Minimize hydroplaning. • FC-5 (3/4” to 7/8” thick) • 100% friction approved aggregate (No RAP). • ARB-12 or PG76-22. • Stabilizing fibers (more asphalt, less draindown). • Granite aggregate requires hydrated lime.

  27. FC-5 Nassau County

  28. Close-up FC-5 Macrotexture

  29. Base Courses (234) • B-12.5 • Superpave Mix • Traffic Level B • May substitute an SP-12.5 • It’s basically the same mix!

  30. Questions/ Comments?

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