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Background
Asphalt Tar– Soluble in petroleum
products– Generally a by-
product of petroleum distillation process
– Can be naturally
– Resistant to petroleum products
– Generally by-product of coke (from coal) production
Can be naturally occurring
Petroleum-Based AsphaltsAsphalt is waste product from refinery processing of crude oil– Sometimes called the “bottom of the barrel”Sometimes called the bottom of the barrel
Properties depend on:– Refinery operations– Composition crude source-dependent
GasolineNaphthaKerosene
Diesel
Motor OilsLube Oil
Asphalt
Barrel of Crude Oil
Asphalt Cement Components
Asphaltenes– Large, discrete solid inclusions (black)
Hi h i it t– High viscosity component
Resins– Semi-solid or solid at room temperature
» Fluid when heated» Brittle when cold
Oils– Colorless liquid– Soluble in most solvents– Allows asphalt to flow
Refinery Operation
LIGHT DISTILLATE
FIELD STORAGEPUMPINGSTATION
HEAVY DISTILLATE
PROCESSUNIT
TOWERDISTILLATIONREFINERY
RESIDUUM
MEDIUM DISTILLATE
UNIT
ASPHALTCEMENTS
FOR PROCESSING INTOEMULSIFIED ANDCUTBACK ASPHALTS
STILL
AIR
AIRBLOWNASPHALT
STORAGE OR
GAS
PETROLEUM
SAND AND WATER
CONDENSERS AND
COOLERS
TUBEHEATER
Types
Asphalt cementsGenerally refinery produced material– Generally refinery produced material
– Air blown asphalt cements Cutbacks– Asphalt cements “cut” with petroleum solvents
Emulsions– Mixture of asphalt cement, water, and emulsifyingMixture of asphalt cement, water, and emulsifying
agent
Air Blown Asphalt Cement
Cutbacks
Rapid cure (RC) (Naphtha or Gasoline)Hi h l tilit f l t– High volatility of solvent
– Tack coats, surface treatmentsMedium cure (MC) (Kerosene)– Moderate volatility– Stockpile patching mix
Slow cure (SC) (Low viscosity oil)Slow cure (SC) (Low viscosity oil)– Low volatility– Prime coat, dust control
Emulsions
Emulsifier gives surface charge to asphalt droplets suspended in water medium– Anionic
» Negative charge» Alkaline» Good with limestones (positive charge)
– Cationic » Positive charge» Positive charge» Acid» Good with silica gravels (negative charge)
Hot
Cold recycling
Bitumen
Water Air
Foamed Bitumen
2 - 3% cold water injected into the hot bitumen will produce foam with an expansion of 10 to 20 times of the original volume
Purchasing of Asphalt Cements
Need to be able to specify desirable characteristicscharacteristics“Desirable characteristics” have evolved over time and with increasing technological advances
Purchasing requires specificationsPurchasing requires specifications
Early Specifications
Lake AsphaltsAppearance– Appearance
– Solubility in carbon disulfidePetroleum asphalts (early 1900’s)– Consistency
»Chewing»Penetration machine
- Measure consistency
Penetration TestingSewing machine needleSpecified load, time, temperature
100 g Penetration in 0.1 mm
Initial After 5 seconds
Penetration Specification
Five Grades• 40 - 50• 60 - 70• 85 - 100• 120 150• 120 - 150• 200 - 300
Viscosity Graded Specifications
Viscosity: the ratio between the applied shear stress and the rate of shear
Definition
stress and the rate of shear.
η = τ / γ
Types of Viscosity Tubes
Asphalt Institute TubeZietfuchs Cross-Arm
Tube
Testing
Absolute viscosityU-shaped tube with– U-shaped tube with timing marks & filled with asphalt
– Placed in 60C bath– Vacuum used to pull
asphalt through tube– Time to pass marks– Viscosity in Pa s (Poise)
40
Penetration GradesAC 40
100)
AR 16000
50
6070
85100
120150
AC 20
AC 10
AC 5
AC 2 5
100
50
osity
, 60C
(140
F) AR 8000
AR 4000
AR 2000
150200300
AC 2.510
5
Visc
o AR 1000
Short Term Binder AgingRolling Thin Film Oven
– Simulates aging from hot mixing and construction
ControlFan
1.3. 9Air jet
Bottle carriage
Penetration0 sec 5 sec
Viscosityvacuum
100g 100g
5 secPenetration
1 .1. 17
AC OR AR
hard
Consistency(pen or viscosity)
Pen limitViscosity limit
soft
A
CB
Viscosity limit
Lower viscosity limit
-15 25 60 135Temperature, C
3- 60/70 AC Asphalts meeting specs
1 .1. 18
SUPERPAVE
-20 20 60 135Pavement Temperature, C
ViscosityWorkability
RuttingFatigueCracking
1.3. 3
FreshFresh&
RTFO
PAVPAV
Rotational Viscometer (Brookfield)
Torque Motor
Inner Cylinder
Thermosel Environmental
Chamber
Digital Temperature Controller
101055
Viscosity, Pa sViscosity, Pa s
Mixing/Compaction Temps
..22
..33
..55
11
Compaction RangeMixing Range
..11100100 110110 120120 130130 140140 150150 160160 170170 180180 190190 200200
Temperature, CTemperature, C
Mixing Range
SUPERPAVE
-20 20 60 135Pavement Temperature, C
ViscosityWorkability
RuttingFatigueCracking
1.3. 3
FreshFresh&
RTFO
PAVPAV
Short Term Binder AgingRolling Thin Film Oven
– Simulates aging from hot mixing and construction
ControlFan
1.3. 9Air jet
Bottle carriage
Rack of individual pans(50g of asphalt / pan)
Pressure Aging Vessel
Bottom of pressure aging
vessel
Vessel Lid Components1.3. 19
Motor
Area for
Parallel Plates
Liquid Bath
SUPERPAVE
-20 20 60 135Pavement Temperature, C
ViscosityWorkability
RuttingFatigueCracking
1.3. 3
FreshFresh&
RTFO
PAVPAV
C l d
Deflection Transducer
Air BearingControl andData Acquisition
Asphalt Beam
Air Bearing
Load CellFluid Bath
LoadingFrameSupports
TemperatureDetector
Bending Beam Rheometer Equipment
Fluid BathFluid BathLoading
Ram
Cooling System
Direct Tension Test
Courtesy of FHWA
SUPERPAVE
-20 20 60 135Pavement Temperature, C
ViscosityWorkability
RuttingFatigueCracking
1.3. 3
FreshFresh&
RTFO
PAVPAV
Superpave Asphalt Binder Specification
The grading system is based on Climate
PG 70 10PG 70 - 10
Performance Grade
Min pavement temperature
Grade
Average 7-day max pavement temperature
Binder Selection & Tests
Select GradePG 76 10
verify GradeG* δ S PG-64-22
• climate• reliability
PG-76-10PG-70-10
• G*, δ, S, m, etc.• temp/vis. profile
G 6
KUWAIT
DHAHRAN
AL-QAISUMAH
AL-WAJH
TABOUKTABOUK R.
BURAYDAH
HAIL
HAIL R.
RAFHANORTH BORDER R.
AL-JAWF
AL-JAWF R.
AL-QURAYYATTURAIF
ARAR
AL-QURAYYAT R.
QATAR
O M A N
U A E
EASTERN PROVINCE
HAFUF
RIYADH
RIYADH REGION
SULAYYIL
ASIR R
BISHABAHA
AL-BAHA R.TAIF
MAKKAHJEDDAH
YANBUMADINAH
MADINAH R.
MAKKAH R.
AL-DAWADMI
BURAYDAH
AL-QASSIM R.
PG 70 - 10
PG 70 - 10
PG 64 - 10 PG 76 - 10
O M A N
NAJRAN R.
NAJRAN SHARURAH
JIZAN
ABHA
JIZAN R.
ASIR R.
KHAMISMUSHAYT
Tentative Temperature Zoning for Asphalt Binder Specifications for the Gulf Countries.
Questions - ?
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