Construction Academy 2014
Florida Department ofTRANSPORTATION
Tanya NashState Materials Office
Florida Department of Transportation
• Asphalt 101• Asphalt Contractor Quality Control Process• Miscellaneous Information, Specification
Changes, and Research
Topics
Florida Department of Transportation
ASPHALT 101
Ground Tire Rubber
Styrene-Butadiene-Styrene(SBS)
0
10
20
30
40
50
60
70
80
90
100
12.5 mm Superpave Gradation Chart
Sieve Size
Pe
rce
nt
Pa
ss
ing
#200
#100
#50
#30
#16
#8
#4
3/8"
1/2"
3/4"
Florida Department of Transportation
• 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
What is an Asphalt Mix?
Aggregate stockpiles
RAP/RAS bin
Emission control system
Storage silo & load out
Liquid asphalt storage tank
Control
roomDrum
Dryer/Mixer
RAP/RAS stockpiles
Florida Department of Transportation
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 (SUperior PERforming asphalt PAVEments).
– Developed to design asphalt pavements that will perform better under the extremes of temperature and loading.
Florida Department of Transportation
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
Florida Department of Transportation
Superpave Mix Design
Select Materials• Binder• Aggregates
Design Aggregate Structure
Design Asphalt Binder
Content
Evaluate Moisture Sensitivity
Low Temperature cracking
Florida Department of Transportation
Asphalt Binders• “Binds” the aggregate
together• Provides…
– the “glue”– lubrication for compaction– Durability (resistance to
cracking)
• The most expensive part of an asphalt mix
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)
Materials
Florida Department of Transportation
FDOT Asphalt Binder Price Index (PG 67-22)
$0
$100
$200
$300
$400
$500
$600
$700
$800
Florida Department of Transportation
Crude Oil
Where Does Asphalt Come From?
Florida Department of Transportation
How Does Crude Get Here?
Pipe
Ship
Florida Department of Transportation
Oil Refinery
Florida Department of Transportation
Fractional Distillation
Florida Department of Transportation
Crude Oil Distillation (Typical)
Florida Department of Transportation
• Grading system based on climate
PG 67-22
Superpave Asphalt Binders
PerformanceGrade
Average 7-daymax pavementdesign temp
Min pavementdesign temp
Florida Department of Transportation
• 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)
Examples of PG Grading System
Florida Department of Transportation
Typical Asphalt Binders
Table 334-2Asphalt Binder Grade for Mixes Contains RAP
Percent RAP Asphalt Binder Grade
0 – 15 PG 67-22
16 – 30 PG 58-22
>30 PG 52-28
The bituminous material specification requirements are outlined in Section 916.
Florida Department of Transportation
• 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)
Modified Asphalt Binders (916)
Florida Department of Transportation
Florida Department of Transportation
Average Cost per Ton of Asphalt Mix
$-
$20.00
$40.00
$60.00
$80.00
$100.00
$120.00
$44.19 $44.63 $49.13
$52.70 $58.33
$68.48
$91.52
$104.32 $98.21
$94.32
$82.79 $85.36
$91.19 $96.30
Florida Department of Transportation
Typical Asphalt Pavement Structure
12” Stabilized Subgrade
1” Friction Course
8” Base (Limerock or Asphalt)
4” Structural Course
Florida Department of Transportation
• 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
Florida Asphalt Mixtures
Florida Department of Transportation
• 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
Superpave – Structural (334)
Florida Department of Transportation
ESAL Examples
15,000 lb0.48 ESAL
6,000 lb0.01 ESAL+ =
34,000 lb1.10
34,000 lb1.10+ =
12,000lb0.20+
0.49 ESALs
2.40 ESALs
Florida Department of Transportation
Mix Design Traffic Levels
Traffic Level ESAL’sA < 300,000 ESAL’sB 300,000 < 3 million ESAL’sC 3 million < 10 million ESAL’sD 10 million < 30 million ESAL’sE ≥ 30 million ESAL’s
Traffic Levels are found in the
Contract
ESALS come from
planning
Florida Department of Transportation
A<300,000 ESAL’s
B300,000 to 3,000,000 ESAL’s
C3,000,000 to 10,000,000 ESAL’s
D10,000,000 to 30,000,000 ESAL’s
E>30,000,000 ESAL’s
Florida Department of Transportation
Florida Department of Transportation
Florida Department of Transportation
Traffic Distribution for State Roads
1%
40%
37%
19%
3%TL-A
TL-B
TL-C
TL-D
TL-E
Florida Department of Transportation
• 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
Dense Graded Friction Courses (337 / 334)
Florida Department of Transportation
• 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
Open-Graded Friction Courses (337)
Florida Department of Transportation
FC-5 Nassau County
Florida Department of Transportation
FC-5 MacrotextureFC-12.5 Microtexture
Florida Department of Transportation
• 12.5 mm Superpave Mix– Traffic Level B– Paid by the square yard (285 – Optional Base)
Superpave Asphalt Base (234)
Florida Department of Transportation
Questions/Comments?