construction academy 2012 asphalt materials
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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 . - PowerPoint PPT PresentationTRANSCRIPT
Construction Academy 2012
Asphalt Materials
Tanya NashState Materials Office
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Topics
Asphalt OverviewAsphalt CQC (Specs 334 and 337)Miscellaneous Information,
Specification Changes, and Research
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Asphalt Overview
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12” Stabilized Subgrade
1” Friction Course
8” Base (Limerock or Asphalt)
4” Structural Course
Typical Asphalt Pavement Structure
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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 5
Average Cost per Ton of Asphalt Mix
Asphalt Binders
“Binds” the aggregate together.Provides…..
the “glue.” lubrication for compaction. durability (resistance to cracking).
The most expensive part of an asphalt mix.
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FDOT Asphalt Binder Price Index (PG 67-22)
Crude Oil
Where does asphalt come from?
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How does crude get here?
Pipeline
Ship
Oil Refinery 11
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0 20 40 60 80 1000
200
400
600
800
1000
CRUDE OIL DISTILLATION (TYPICAL)
PERCENT DISTILLED
TEM
PER
ATU
RE
oF
GAS
GASOLINE
DIESEL
KEROSINE
GAS OIL
ASPHALT
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Superpave Asphalt Binders
Grading system based on climate
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PG 67-22
PerformanceGrade
Average 7-daymax pavementdesign temp
Min pavementdesign temp
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)
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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
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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.
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Typical FL Mix TypesStructural 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
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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
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15,000 lb0.48 ESAL
6,000 lb0.01 ESAL+ =
34,000 lb
1.10
34,000 lb
1.10+ =
12,000lb
0.20+
0.49 ESALs
ESAL Examples
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2.40 ESALs
Mix Design Traffic Levels
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Traffic Level ESAL’s
A < 300,000 ESAL’s
B 300,000 < 3 million ESAL’s
C 3 million < 10 million ESAL’s
D 10 million < 30 million ESAL’s
E ≥ 30 million ESAL’s
ESALS come from
planning
Traffic Levels are found in
the Contract
Traffic Distribution for State Roads
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1%
40%
37%
19%3%
TL-ATL-BTL-CTL-DTL-E
C
DB
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 design25
Fine graded SP-12.5 mix27
Coarse graded SP-19.0 mix28
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.
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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.
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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.31
FC-5 Nassau County
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Close-up FC-5 Macrotexture 33
Base Courses (234)
B-12.5Superpave Mix
Traffic Level BMay substitute an SP-12.5
It’s basically the same mix!
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Questions/ Comments?
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