asphalt 101: an introduction to hot mix asphaltwhy study asphalt? highway expenditures in 2008 –...
TRANSCRIPT
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Asphalt 101:
An Introduction to Hot Mix Asphalt
Materials
-Part I-
Asphalt and Modified Asphalts
1
Asphalt 101:
An Introduction to Hot Mix Asphalt
Materials
-Part I-
Asphalt and Modified Asphalts
Scott Shuler
CSU
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2
Glue:Scott Shuler
Sticky Glue:Marshall Shackelford
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Why Study Asphalt?
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Why Study Asphalt?
of all the ROADS IN THE U. S. A.(miles)
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Why Study Asphalt?
of all the ROADS IN THE U. S. A.(miles)
Concrete Earth Gravel Asphalt
100,000
3
Why Study Asphalt?
of all the ROADS IN THE U. S. A.(miles)
Concrete Earth Gravel Asphalt
100,000 400,000
3
Why Study Asphalt?
of all the ROADS IN THE U. S. A.(miles)
Concrete Earth Gravel Asphalt
100,000 400,000
1,300,000
3
Why Study Asphalt?
of all the ROADS IN THE U. S. A.(miles)
Concrete Earth Gravel Asphalt
100,000 400,000
1,300,000
2,200,000
95%5%
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Why Study Asphalt?
4
Why Study Asphalt?
Highway Expenditures in 2008– $140 Billion
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Why Study Asphalt?
Highway Expenditures in 2008– $140 Billion
Hot Mix Asphalt Placed Annually– 500 Million Tons– $10.5 Billion
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Why Study Asphalt?
Highway Expenditures in 2008– $140 Billion
Hot Mix Asphalt Placed Annually– 500 Million Tons– $10.5 Billion
Employment– 300,000 directly– 600,000 additionally
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Why Study Asphalt?
Highway Expenditures in 2008– $140 Billion
Hot Mix Asphalt Placed Annually– 500 Million Tons– $10.5 Billion
Employment– 300,000 directly– 600,000 additionally
Asphalt is Largely Empirical– “Old Timers” Retiring
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What Are Asphalt Pavements ?
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What Are Asphalt Pavements ?
Rocks Glued Together With Asphalt
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What Are Asphalt Pavements ?
Rocks Glued Together With Asphalt
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What Are Asphalt Pavements ?
Rocks Glued Together With Asphalt
About 86% n Rocks Volume
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What Are Asphalt Pavements ?
Rocks Glued Together With Asphalt
About 86%
About 10%
n Rocks
n Asphalt
Volume
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What Are Asphalt Pavements ?
Rocks Glued Together With Asphalt
About 86%
About 10%
4%
n Rocks
n Asphalt
n Air
Volume
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Let’s Consider the Glue
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Among the Oldest Engineering Materials– Waterproofing of Ships
Sumeria-6000 BC
Let’s Consider the Glue
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Among the Oldest Engineering Materials– Waterproofing of Ships
Sumeria-6000 BC– Waterproofing of Baths and Tanks “Earth Butter”
Mohenjo-Daro Indus Valley-3000 BC
Let’s Consider the Glue
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Among the Oldest Engineering Materials– Waterproofing of Ships
Sumeria-6000 BC– Waterproofing of Baths and Tanks “Earth Butter”
Mohenjo-Daro Indus Valley-3000 BC– Mummies
Egypt-2600 BC
Let’s Consider the Glue
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Among the Oldest Engineering Materials– Waterproofing of Ships
Sumeria-6000 BC– Waterproofing of Baths and Tanks “Earth Butter”
Mohenjo-Daro Indus Valley-3000 BC– Mummies
Egypt-2600 BC
– Bible References Noah’s Arc Waterproofed with “Pitch” Genesis 6:14.20 Moses’ Basket Coated with “Bitumen” and “Pitch” Exodus 2:3.24
Let’s Consider the Glue
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Among the Oldest Engineering Materials– Waterproofing of Ships
Sumeria-6000 BC– Waterproofing of Baths and Tanks “Earth Butter”
Mohenjo-Daro Indus Valley-3000 BC– Mummies
Egypt-2600 BC
– Bible References Noah’s Arc Waterproofed with “Pitch” Genesis 6:14.20 Moses’ Basket Coated with “Bitumen” and “Pitch” Exodus 2:3.24
– Roman Buildings Waterproofed and Cemented Romans called the source Lacus Asphaltites
Let’s Consider the Glue
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So It Will Work!
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So It Will Work!
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So It Will Work!
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So It Will Work!
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Reed Boat, aka Gufa
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9
Bitumen
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Bitumen
Asphalts Tars
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Bitumen
Asphalts Tars
PetroleumNatural Coal
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Asphalts
10
Asphalts
PetroleumNatural
10
Asphalts
PetroleumNatural
Lake
10
Asphalts
PetroleumNatural
LakeTrinidad
10
Asphalts
PetroleumNatural
LakeTrinidad
La Brea
10
Asphalts
PetroleumNatural
Lake
Rock
Trinidad
La Brea
10
Asphalts
PetroleumNatural
Lake
Rock
Trinidad
La Brea
KY
10
Asphalts
PetroleumNatural
Lake
Rock
Trinidad
La Brea
KY
TX
10
Asphalts
PetroleumNatural
Lake
Rock
Trinidad
La Brea
KY
TX
AB
10
Asphalts
PetroleumNatural
Lake
Rock
Asphaltites
Trinidad
La Brea
KY
TX
AB
10
Asphalts
PetroleumNatural
Lake
Rock
Asphaltites
Trinidad
La Brea
KY
TX
AB
UT-Gilsonite
10
Asphalts
PetroleumNatural
Lake
Rock
Asphaltites
Cements LiquidsTrinidad
La Brea
KY
TX
AB
UT-Gilsonite
10
Asphalts
PetroleumNatural
Lake
Rock
Asphaltites
Cements Liquids
Emulsions Cutbacks
Trinidad
La Brea
KY
TX
AB
UT-Gilsonite
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Crude Oil Variations
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Crude Oil Variations
Venezuelan Nigerian Light
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Crude Oil Variations
Gasoline 3%
Venezuelan
Gasoline 33%
Nigerian Light
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Crude Oil Variations
Gasoline 3%Kerosene 6%
Venezuelan
Gasoline 33%
Kerosene 20%
Nigerian Light
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Crude Oil Variations
Gasoline 3%Kerosene 6%
Gas Oil 33%
Venezuelan
Gasoline 33%
Kerosene 20%
Gas Oil 46%
Nigerian Light
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Crude Oil Variations
Gasoline 3%Kerosene 6%
Gas Oil 33%
Residuum 58%
Venezuelan
Gasoline 33%
Kerosene 20%
Gas Oil 46%
Residuum 1%
Nigerian Light
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Refining Methods
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Refining Methods
Distillation– Atmospheric– Vacuum
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Refining Methods
Distillation– Atmospheric– Vacuum
Solvent Deasphalting– Propane and Butane Extraction of Lube Oils– Result is Very Hard Precipitate AC
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Refining Methods
Distillation– Atmospheric– Vacuum
Solvent Deasphalting– Propane and Butane Extraction of Lube Oils– Result is Very Hard Precipitate AC
Solvent Extraction (ROSE)– Separates AC into Asphaltenes/Resins/Oils– Result is Blended to Produce Spec AC
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Petroleum Asphalts
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Petroleum Asphalts
Oil Well
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Petroleum Asphalts
CrudeStorage
Oil Well
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Petroleum Asphalts
CrudeStorage
Oil Well
Atm
os S
till
60-700F
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Petroleum Asphalts
CrudeStorage
Oil Well
Atm
os S
till
Con
dens
er
60-700F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Oil Well
Atm
os S
till
Con
dens
er
60-700F
60-325F
325-500F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Oil Well
Atm
os S
till
Con
dens
er
60-700F
60-325F
325-500F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Vacu
um S
till
Oil Well
Atm
os S
till
Con
dens
er
60-700F
60-325F
325-500F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Gas Oil
Vacu
um S
till
Oil Well
Atm
os S
till
Con
dens
er
650-1050F60-700F
60-325F
325-500F
650-850F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Gas Oil
Vacu
um S
till
AsphaltCements
Oil Well
Atm
os S
till
Con
dens
er
650-1050F60-700F
60-325F
325-500F
650-850F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Gas Oil
Vacu
um S
till
AsphaltCements
Emulsions
Oil Well
Atm
os S
till
Con
dens
er
H 2O
650-1050F60-700F
60-325F
325-500F
650-850F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Cutbacks
Gas Oil
Vacu
um S
till
AsphaltCements
Emulsions
Oil Well
Atm
os S
till
Con
dens
er
H 2O
Gas/Kero650-1050F60-700F
60-325F
325-500F
650-850F
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Petroleum Asphalts
CrudeStorage
GasolineKerosene
Cutbacks
Gas Oil
Vacu
um S
till
AsphaltCements
Emulsions
Oil Well
Atm
os S
till
Con
dens
er
H 2O
RoofingAsphalts
Air
Gas/Kero650-1050F60-700F
60-325F
325-500F
650-850F
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Asphalt Types
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Asphalt Types
Asphalt Cement
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Asphalt Types
Asphalt Cement Liquid Asphalts
– Emulsified Asphalts– Cutback Asphalts
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Behavior of Asphalt Cements
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Behavior of Asphalt Cements
Asphalt is Viscoelastic– Viscous (Flows) at High Temperatures
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Behavior of Asphalt Cements
Asphalt is Viscoelastic– Viscous (Flows) at High Temperatures– Elastic at Low Temperatures
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Behavior of Asphalt Cements
Asphalt is Viscoelastic– Viscous (Flows) at High Temperatures– Elastic at Low Temperatures
Silly Putty is Viscoelastic– Pull it Slowly- It stretches – same as high temperature
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Behavior of Asphalt Cements
Asphalt is Viscoelastic– Viscous (Flows) at High Temperatures– Elastic at Low Temperatures
Silly Putty is Viscoelastic– Pull it Slowly- It stretches – same as high temperature– Pull it Rapidly – It breaks – same as low temperature
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Asphalt Performance depends
on Environment and Traffic
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Asphalt Performance depends
on Environment and Traffic
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Hot
Beh
avio
r
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Weak BehaviorH
ot B
ehav
ior
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Weak BehaviorH
ot B
ehav
ior
Cold Behavior
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Temperature Effects
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Temperature Effects
100°F
1 Hour
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Temperature Effects
30°F
100°F
1 Hour
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Temperature Effects
30°F
100°F
1 Hour
10 Hours
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Temperature Effects
30°F
100°F
1 Hour
10 Hours
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Material Effects
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Material Effects
30°F
1 Hour
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Material Effects
30°F
1 Hour
Hard Asphalt Softer Asphalt
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Achieving
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SUPERPAVE
To The Rescue !
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SUPERPAVE
To The Rescue !
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SPECIFYING PERFORMANCE
Based on Climate
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SPECIFYING PERFORMANCE
Based on Climate
PG 64 - 22
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SPECIFYING PERFORMANCE
Based on Climate
PG 64 - 22
Performance Grade
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SPECIFYING PERFORMANCE
Based on Climate
PG 64 - 22
Performance Grade
Average 7-day max pavement temperature, C
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SPECIFYING PERFORMANCE
Based on Climate
PG 64 - 22
Performance Grade
Average 7-day max pavement temperature, C
Min pavement temperature, C
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Dynamic Shear
Rheometer
Tests in PG Specifications
Bending Beam
Rheometer
Rotational Viscometer
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Caused by Warm Weather, Traffic and Wrong Mixture
Cou
rtes
y of
FH
WA
Permanent Deformation ( )
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High Temperature or,Slow Loading Behavior, aka Rutting
High Pavement Temperature– Desert climates– Summer temperatures
Sustained loads– Slow moving trucks– Intersections
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High Temperature or,Slow Loading Behavior, aka Rutting
High Pavement Temperature– Desert climates– Summer temperatures
Sustained loads– Slow moving trucks– Intersections
100°F
1 Hour
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Courtesy of FHWA
Thermal Cracking
Caused by Low Temperatures, Rapid Loads, Hard Binder
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Low Temperature, or Fast Loading Behavior-aka Cracking
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Low Temperature, or Fast Loading Behavior-aka Cracking
Low Temperature– Cold climates– Winter
26
Low Temperature, or Fast Loading Behavior-aka Cracking
Low Temperature– Cold climates– Winter
Rapid Loads– Fast moving trucks
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Low Temperature, or Fast Loading Behavior-aka Cracking
Low Temperature– Cold climates– Winter
Rapid Loads– Fast moving trucks
σ
ε
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Low Temperature, or Fast Loading Behavior-aka Cracking
Low Temperature– Cold climates– Winter
Rapid Loads– Fast moving trucks
σ
ε
Cracking Failure
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Aging
Asphalt reacts with oxygen– Becomes harder, more brittle– More Elastic, Less Viscous
Short term– During Mixing with Aggregates (280F-330F)
Long term– In Pavement– Air, Water, Sun
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Asphalt Plant and Construction Aging
Rolling Thin Film Oven (RTFO)
Fan
Rotating Bottle
Carriage
Blowing Air
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Pressure Aging Vessel
Pressure Aging Vessel
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Pressure Aging Vessel
50 grams of Asphalt in Each Pan
Pressure Aging Vessel
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Pressure Aging Vessel
Courtesy of FHWA
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RV
DSR
BBR
Rutting, Hardening and Fatigue
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1 cycle
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1 cycle
Fixed Lower Plate
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1 cycle
Fixed Lower Plate
Oscillating Upper Plate
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1 cycle
CA
B
Fixed Lower Plate
Oscillating Upper Plate
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1 cycle
CA
B
Fixed Lower Plate
Oscillating Upper PlateAsphalt Glued In-Between
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1 cycle
Time
CA
B
Fixed Lower Plate
Oscillating Upper PlateAsphalt Glued In-Between
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1 cycle
TimeAA
B
C
CA
B
Fixed Lower Plate
Oscillating Upper Plate
A
Asphalt Glued In-Between
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1 cycle
TimeAA
B
C
CA
B
Fixed Lower Plate
Oscillating Upper Plate
A
Now, Measure the Force Required to Rotate the Upper
Plate
And, Measure When Movement Occurs in
the Binder
Asphalt Glued In-Between
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33
Elastic
Time
33
Elastic
TimeAA
B
C
Strain
Strain Occurs With Stressδ = 0o
A
Stress
33
Elastic Viscous
TimeAA
B
C
Strain
Strain Occurs With Stressδ = 0o
A
Stress
33
Elastic Viscous
TimeAA
B
C
Strain
Strain Occurs With Stressδ = 0o
AA
B
C
AA
Stress
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Elastic Viscous
TimeAA
B
C
Strain
Strain Occurs With Stressδ = 0o
Strain Lags Stressδ = 90o
AA
B
C
AA
Stress
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δ
34
Elastic, G’
δ
34
Vis
cous
, G”
Elastic, G’
δ
34
Vis
cous
, G”
Elastic, G’
Complex M
odulus, G*
δ
Complex Modulus is the vector sum of
Elastic and Viscous Components
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> Early part of pavement lifeHeavy Trucks
Controlling Rutting
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> Early part of pavement lifeHeavy Trucks
Controlling RuttingAddressed by: G*/sin δ on Unaged binder > 1.00 kPa G*/sin δ on Lab Aged binder > 2.20 kPa
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Fatigue Cracking
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Caused by repeated traffic loads in wheel pathsFatigue Cracking
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Fatigue Cracking
Addressed by intermediate temperature stiffness– G*sin δ on RTFO & PAV
aged binder < 5000 kPa
> Later part of pavement service life
38
RV DSR BBR
Thermal Cracking
39
Bending Beam Rheometer
Load Cell
Deflection Transducer
Fluid Bath
Computer
40
BBR Measures Stiffness at Low Temperatures using Beam Theory
40
BBR Measures Stiffness at Low Temperatures using Beam Theory
S(t) =PL3
4 bh3 δ (t)
Creep stiffness at
t = 60 secs
40
BBR Measures Stiffness at Low Temperatures using Beam Theory
S(t) =PL3
4 bh3 δ (t)
Creep stiffness at
t = 60 secs100 grams
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BBR Measures Stiffness at Low Temperatures using Beam Theory
S(t) =PL3
4 bh3 δ (t)
Creep stiffness at
t = 60 secs100 grams
Clear Span of Beam, 102 mm
40
BBR Measures Stiffness at Low Temperatures using Beam Theory
S(t) =PL3
4 bh3 δ (t)
Creep stiffness at
t = 60 secs100 grams
Clear Span of Beam, 102 mm
Beam Width, 12.5 mm
Beam Thickness, 6.25 mm
40
BBR Measures Stiffness at Low Temperatures using Beam Theory
S(t) =PL3
4 bh3 δ (t)
Creep stiffness at
t = 60 secs100 grams
Clear Span of Beam, 102 mm
Beam Width, 12.5 mm
Beam Thickness, 6.25 mm
Deflection at t = 60 secs
41
Bending Beam Rheometer
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
8 15 30 60 120 240
Log
Cre
ep
Stif
fnes
s, S
(t)
Log Loading Time, t (sec)
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
8 15 30 60 120 240
Log
Cre
ep
Stif
fnes
s, S
(t)
Log Loading Time, t (sec)
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
8 15 30 60 120 240
Log
Cre
ep
Stif
fnes
s, S
(t)
Log Loading Time, t (sec)
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
8 15 30 60 120 240
Log
Cre
ep
Stif
fnes
s, S
(t)
Log Loading Time, t (sec)
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
8 15 30 60 120 240
Log
Cre
ep
Stif
fnes
s, S
(t)
Log Loading Time, t (sec)
m
41
Bending Beam Rheometer Creep Stiffness Stiffness v. Time Slope
8 15 30 60 120 240
Log
Cre
ep
Stif
fnes
s, S
(t)
Log Loading Time, t (sec)
m
42
Thermal Cracking
Question: How Much Should the Asphalt Be Able to Stretch before Breaking?
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Thermal Cracking
Question: How Much Should the Asphalt Be Able to Stretch before Breaking?
Answer: at least 1%
How: Find the Temperature Where the Asphalt Can Stretch 1% or More
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Direct Tension Test
Δ Le
43
Direct Tension Test
Δ Le
43
Direct Tension Test
Δ Le
Δ L
Load
43
Direct Tension Test
Δ Le
Δ L
Load
Strain εf
σf
43
Direct Tension Test
Δ Le
Δ L
Load
Strain εf
σf
43
Direct Tension Test
Δ Le
Δ L
Load
Stress = σ = P / A
Strain εf
σf
44
RVDynamic
Shear Rheometer
ConstructionBut Will it Flow for Mixing ?
Bending Beam
Rheometer
Rotational Viscometer
45
Rotational Viscometer (Brookfield)
Inner Cylinder
Torque Motor
Thermosel Environmental
Chamber
Digital Temperature Controller
46
Spec Requirements
Make Sure It’s Not Too Thick– Keep Viscosity Below 3 Pa-sec at 275F (135C)
47