Asphalt Paving Materials
Chapter 6
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Bituminous Materials
BituminousMaterials
NaturalAsphalts
PetroleumAsphalts
Tar &Pitch
(1800s) (late 1900s)(early 1900s)
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Natural Asphalt
Rock Asphalt Native AsphaltAsphalt Sand
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Asphalt Sands
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Asphalt Sands
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Native Asphalt
La Brea Tar Pits
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Native Asphalt
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Source: Geological Society of Trinidad and Tobago (www.gstt.org)
Native Asphalt
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Native Asphalt
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http://www.flickr.com/photos/striderv/4314238332/lightbox/
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Native Asphalt
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Bituminous Materials
BituminousMaterials
NaturalAsphalts
PetroleumAsphalts
Tar &Pitch
(1800s) (late 1900s)(early 1900s)
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Chickamauga Coking Ovens
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Dunlap, TN Coking Ovens
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Bituminous Materials
BituminousMaterials
NaturalAsphalts
PetroleumAsphalts
Tar &Pitch
(1800s) (late 1900s)(early 1900s)
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Crude Oil ChemistryOils
Resin-coated asphaltenes
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Crude Oil
AromaticHydrocarbons (oils)
SaturatedHydrocarbons
Light Crude Heavy Crude
“oils”“oils”
“oils”
“oils”
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Petroleum Distillation
TubeHeater
Bitumen Residuum38-70 Carbons
Crude
DistillationColumn
Diesel Oil15-38 Carbons
Kerosene10-14 Carbons
Naphtha5-10 Carbons
Gasoline1-4 Carbons
Butane & Propane1-4 Carbons
550ºC
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Crude Oil
33
20
16
30
58
67
26
21
14
10
28
27
BitumenResiduum
GasolineKerosene
Lt. Gas Oil
Hv. Gas Oil
BoscanVenezuela
ArabianHeavy
NigeriaLight
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Liquefying Asphalt CementAsphalt Cement
(Bitumen Residuum)
Heatit
Suspendit in water
Thin it withsolvents
Hot-MixAsphalt
EmulsifiedAsphalt
CutbackAsphalt
Temperature-Viscosity
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Peanut Butter
Ketchup
Chocolate Syrup
Honey
Tomato Juice
Vegetable Oil
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Cutback Asphalt
Rapid Curing (RC)Asphalt cement thinned with gasoline or naphthaUsed for tack and seal coats (surface applications)
Medium Curing (MC)Asphalt cement thinned with keroseneUsed for prime coats, cold-laid pavement bases
Slow Curing (SC)Asphalt cement thinned with diesel oil or gas oilsUsed for cold-laid pavement bases
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Cutback Asphalt
30
30-60
70
70-140
250
250-500
800
800-1600
3000
3000-6000
Solvent
Asphalt
Grade
Kinematic Viscosity@ 140°F (CS)
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Emulsified AsphaltWater & emulsifying agent
5-10 micron spheres of asphalt
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Emulsified Asphalt
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Emulsified Asphalt
LIMESTO
NE
SILICA
Anionic Emulsifier Cationic Emulsifier
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Emulsified Asphalt
Rapid Setting (RS or CRS)Used for surface coats, penetration macadam
Medium Setting (MS or CMS)Used for open-graded asphalt-treated base
Slow Setting (SS or CSS)Used for dense-graded asphalt-treated base
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Asphalt Cement Grading
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Asphalt Cement Performance
ElasticSolid
TrueLiquid
ViscoelasticSolid
ViscousLiquid
FatigueCracking
RuttingShoving
DrainDown
ThermalCracking
AverageServiceTemp
MaximumServiceTemp
MixingPlacingTemp
MinimumServiceTemp
0ºF 300ºF130-150ºF75-80ºF
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Thermal Cracking
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Fatigue Cracking
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Fatigue Cracking
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Rutting
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Rutting
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Shoving
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Shoving
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Asphalt Cement Performance
ElasticSolid
TrueLiquid
ViscoelasticSolid
ViscousLiquid
PenetrationNumber
AbsoluteViscosity
KinematicViscosity
AverageServiceTemp
MaximumServiceTemp
MixingPlacingTemp
MinimumServiceTemp
0ºF 275ºF77ºF 140ºF
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Penetration Test
0 seconds 5 seconds
100 g
77oF
Penetration
100 g
Penetration Number = Penetration in tenths of a millimeter
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Asphalt Penetrometer
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Penetration GradingBased on penetration index at 77°F:
Grade 40–50Grade 60–70Grade 85–100Grade 120–150Grade 200–300
Must also meet ductility, flashpoint, and retained penetration (aging) criteria
TDOT
Penetration Grading
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Ductility
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Ductility(Taken from The Asphalt Institute Manual ES-1, Second Edition)
77oF
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Thin-Film Oven Test
325oF
5-6 rpm5 hrs
Simulates aging of asphalt cement during mixing and laydown
samplepans
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Thin-Film Oven
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Penetration Grading
PRO· Done at average service temperature· Easy test, inexpensive equipment· Test is done at room temperature
CON· Empirical test· Doesn’t specifically address aging· Doesn’t capture temperature susceptibility
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Penetration Grading
Temperature
Pen
77oF
HotSummer
AverageService
ColdWinter
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Viscosity GradingBased on the absolute viscosity at 140oF:
AC-2.5AC-5AC-10AC-20AC-30AC-40
Must also meet ductility, penetration (77oF), kinematic viscosity (275oF), and aging criteria
Numbers correspondto absolute viscosityin hundreds of poiseTDOT
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Viscosity Grading
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Absolute Viscosity
• If a fluid with a viscosity = 1 Pa·s is placed between two plates and one plate is pushed sideways with a shear stress = 1 Pa it will move a distance equal to the thickness of the layer in one second.
11
Absolute viscosity of water at 20ºC = 0.001 Pa·s = 0.01 poise0.01 poise ≡ 1 centipoise
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Absolute Viscosity(Taken from The Asphalt Institute Manual ES-1, Second Edition)
VACUUM VACUUM
Asphalt InstituteViscometer
Cannon ManningViscometer
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Viscosity of Common MaterialsWater 1 centipoise
Cream 20 centipoise
Vegetable Oil 100 centipoise
Tomato Juice 200 centipoise
Honey 2000 centipoise
Chocolate Syrup 10000 centipoise
Sour Cream 20000 centipoise
Ketchup 50000 centipoise
Peanut Butter 150000 centipoise
Vegetable Shortening 1000000 centipoise
AC @ 275F
AC @ 140F
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Kinematic Viscosity
Absolute ViscosityKinematic Viscosity
Fluid Density
3cmg1poise1
stoke1
Kinematic viscosity of water at 20ºC = 0.01 stoke0.01 stoke ≡ 1 centistoke
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Kinematic Viscosity(Taken from The Asphalt Institute Manual ES-1, Second Edition)
Zeitfuchs Cross-Arm Viscometer
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Viscosity Grading
Temperature
Vis
140oF
HotSummer
MixingCompacting
AverageService
ColdWinter
77oF–10oF 275oF
Pen
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Viscosity Grading
PRO· Fundamental material property· Done at maximum service temperature· Includes high & average temperature criteria
CON· Harder to run, more expensive equipment· Doesn’t specifically address long-term aging· Doesn’t consider low-temperature cracking