PAVING ASPHALTSOrigins, properties, manufacture and use

PAVING ASPHALTSOrigins, properties, manufacture and use

Dr. Ludo Zanzotto

Bituminous Materials Chair

Faculty of Engineering

University of Calgary

May 2001

Dr. Ludo Zanzotto

Bituminous Materials Chair

Faculty of Engineering

University of Calgary

May 2001

Historical BackgroundHistorical Background

One of the oldest engineering materials “asphaltos” - sticky, firm - Greek “jatu-krit - pitch creating - Latin: “pixtumen” Use:

– Sumerians (3000 B.C.) - building purposes– Egyptians (2500 B.C.) - “mumyia” - mummy– Biblical times (2500 - 1500 B.C.)

• Noah’s ark - waterproofing

• Tower of Babel - mortar

• Paving

Sources and Manufacture of AsphaltSources and Manufacture of Asphalt

Sources– natural asphalt– crude oil

Asphalt manufacture– distillation - oxidation– extraction - modification– cracking processes

Paving asphalt represents 3 ~ 4 % of the total annual crude oil throughput in USA and Canada

Yield of Asphalt from Different Yield of Asphalt from Different Crude OilsCrude Oils

API DegreesSP.Gravity% Sulfur

BOSCANVENEZUELA

10.1.9996.4

ARABIANHEAVY

28.2.8862.8

NIGERIALIGHT38.1.8340.2

36

7

26

58

21

14

10

28

27

33

20

16

30

1

GasolineKerosene

Lt. Gas Oil

Hv. Gas Oils

BitumenResiduum

Vol. %

Useage of AsphaltUseage of Asphalt

Canadian market (1999).... 3.75 millions of t/year USA market (1999)............38.00 millions of t/year World market................~ 130.00 millions of t/year

80 ~ 90 % of asphalts are used in pavements 10 ~ 20 % of asphalts are used in roofing,

waterproofing and for other purposes

World: 2.0 ~ 2.5 billions t/year of asphalt paving mixes

Potential Asphalt Production from Potential Asphalt Production from Heavy Oils in Western CanadaHeavy Oils in Western Canada

Recoverable heavy oil in Western Canada: 3.5 ~ 7.0 billions of tons

Potential production of asphalt: 1600 ~ 2800 millions of tons

Price of asphalt in USA (spring 2001): US $ 100 ~ 150/t

Price of asphalt in Canada (spring 2001): US $ 150 ~ 180/t

Value of Western Canadian Asphalt: US $ 160 ~ 420 billion

Total Existing Length of Roads and Total Existing Length of Roads and Streets in USAStreets in USA

Total Mileage6,243,000 kilometers (3,880,000 miles)

Paved Mileage *3,466,000 kilometers (2,154,000 miles)

* 94% asphalt surfaced

Total Existing Mileage of Roads and Streets in U.S.A.

Portland Cement Concrete 200,000 kms (124,000 miles)

Earth 603,000 kms (375,000 miles)

Gravel or similar 2,174,000 kms (1,351,000 miles)

Asphalt 3,267,000 kms (2,030,000 miles)

Source: Federal High Administration

Number of Refineries MarketingNumber of Refineries MarketingPaving Asphalt in USA and CanadaPaving Asphalt in USA and Canada

Crude Oil Throughput in US and Crude Oil Throughput in US and Canadian RefineriesCanadian Refineries

0

10

20

30

40

Nu

mb

er

of

Re

fin

eri

es

<5 5-10 10-15 15-20 20-25 25-30 30-35 35-40 40-50

Throughput (10,000 bpd)

Paving Asphalt Production Capacity Paving Asphalt Production Capacity of US and Canadian Refineriesof US and Canadian Refineries

0

2

4

6

8

10

12

14

Nu

mb

er

of

Re

fin

eri

es

<5 5-7.5 7.5-10 10-20 20-30 30-40 40-50 50-60 >60

Asphalt Production Capacity (100 tpd)

Composition and Structure of AsphaltComposition and Structure of Asphalt

Physical and chemical character of asphalt is determined by:– composition of crude oil– method of crude oil and asphalt processing

Asphalt: complex, multicomponent, colloidal system

Asphalt is composed of a multitude species which differ by:– molecular mass, chemical structure, polarity

Molecular mass between 400 - 3000 D Carbon skeleton: 25 - 150 atoms

Composition and Structure of Asphalt (Cont’d)Composition and Structure of Asphalt (Cont’d)

Composition varies considerably among asphalts manufactured from different crude oils

The largest portion of paving asphalts are produced as vacuum residues with the cut point between 425°C and 565°C

Relatively small difference in elemental analysis– C: 80.0 ~ 85.0 %– H: 7.8 ~ 8.3 %– S: 1.0 ~ 7.0 %– O: 2.7 ~ 5.0 %

Composition and Structure of Asphalt (Cont’d)Composition and Structure of Asphalt (Cont’d)

Group composition:– saturates– naphthene aromatics– polar aromatics– asphaltenes

Composition and Structure of Asphalt (Cont’d)Composition and Structure of Asphalt (Cont’d)

Hypothetical structure of asphaltene

Composition and Structure of Asphalt (Cont’d)Composition and Structure of Asphalt (Cont’d)

Unit sheet mass: 1 000 - 4 000 D

Cluster or particle mass: 4 000 - 10 000 D

Micelle mass: 40 000 - 40 000 000 D

Properties of AsphaltProperties of Asphalt

Critical conditions during construction and service– Construction:

• mixing

• spreading appropriate viscosity

• compacting

– Service:

• plastic deformation (rutting)

• thermal cracking

• fatigue cracking

• water sensibility

Properties of Asphalt (Cont’d)Properties of Asphalt (Cont’d)

-50 0 50 100 150

T [°C]

Consistency Consistency

Flexibility

Flexibility Resistance todeformation

Mixing

Resistanceto deformation

Loading Tim e [s]10

-s10

10

IDEAL BEHAVIO UR

-50 0 50 100 150

T [°C]

Consistency Consistency

Loading Tim e [s]10 -s 1010

Too brittle Too brittle

Too soft

Too soft

REAL BEHAVIO UR

Specifications of Paving AsphaltsSpecifications of Paving Asphalts

The role of specifications:– specify properties that directly reflect asphalt

behaviour– express these properties in physical units– provide limits for those properties to exclude

poor performing products– provide information from which the service

performance can be predicted Important properties of asphalt:

– mechanical– adhesive– durability

Specifications of Paving Asphalts (Cont’d)Specifications of Paving Asphalts (Cont’d)

Conventional tests used for asphalt characterization:– penetration, ductility, softening point R&B, flash

point, spot test, Fraass breaking point….. Ageing characteristics:

– Thin Film Oven Test, Rolling Thin Film Oven Test, Pressure Aging Vessel…

Rheological tests:– Bending Beam Rheometer, Direct tension Test,

Dynamic Shear Rheometer

Specifications of Paving Asphalts (Cont’d)Specifications of Paving Asphalts (Cont’d)

Beginning of specifications - around 1900 Classification of asphalts for commercial

purposes in the first half of the century - exclusively conventional tests

First: grading test - penetration at 25°C 1960’s in USA: grading test - viscosity at 60°C Canada: hybrid - penetration/viscosity 1990’s in USA : Superpave specification

(“performance related”)

Classical Penetration- Based Classical Penetration- Based SpecificationSpecification

Min Max Min Max Min Max Min Max Min Max

Penetration @ 77°F(25°C) 100g, 5s 40 50 60 70 85 100 120 150 200 300

Flash Point, °F (Cleveland open cup) 450 --- 450 --- 450 --- 425 --- 350 ---

Ductility at 77°F (25°C) 5cm/min, cm 100 --- 100 --- 100 --- 100 --- 100A ---

Solubility in trichloroethylene, % 99 --- 99 --- 99 --- 99 --- 99 ---

Retained penetration after thin-film 55+ --- 52+ --- 47+ --- 42+ --- 37+ ---oven test, %

Ductility at 77°F (25°C) 5cm/min, cm --- --- 50 --- 75 --- 100 --- 100A ---after thin-film oven test

40-50 60-70 85-100 120-150 200-300

Penetration Grade

REQUIREMENTS FOR ASPHALT CEMENT FOR USE IN PAVEMENT CONSTRUCTIONASTM D946

A If ductility at 77°F (25°C) is less than 100 cm, material will be accepted if ductility at 60°F (15.5°C) is 100 cm minimum at the pull rate of 5 cm/min

Viscosity-Based SpecificationViscosity-Based Specification

AC-2.5 AC-5 AC-10 AC-20 AC-40

Viscosity, 140°F (60°C), P 250 ± 50 50 ± 100 1000 ± 200 2000 ± 400 4000 ± 800

Viscosity, 275°F (135°C), min, cSt 80 110 150 210 300

Penetration, 77°F (25°C), 100g, 5s, min 200 120 70 40 20

Flash point, Cleveland open cup, min, °F (°C) 325 (163) 350 (177) 425 (219) 450 (232) 450 (232)

Solubility in trichloroethylene, min, % 99 99 99 99 99

Tests on residue from thin-film oven test:

Viscosity, 140°F (60°C), max, P 1250 2500 5000 10,000 20,000 Ductility, 77°F (25°C), 5 cm/min, min, cm 100A 100 50 20 10

VISCOSITY GRADE

REQUIREMENTS FOR ASPHALT CEMENT, VISCOSITY GRADED AT 140°F (60°C)ASTM D3381

Note: Grading based on original asphalt

A If ductility is less than 100, material will be accepted if ductility at 60°F (15.5°C) is 100 minimum at a pull rate of 5 cm/min

Canadian Federal SpecificationCanadian Federal Specification

Penetration at 25°C [dmm]

Canadian Federal Specification (Cont’d)Canadian Federal Specification (Cont’d)

Canadian Federal Specification (Cont’d)Canadian Federal Specification (Cont’d)

Grades

Requirements

Penetration at 25°C100g and 5s, 0.1mm

*Viscosity at 60°C, Pa.s or*Viscosity at 135°C, mm2/s

*Group A

*Group B

*Group C

Flash Point (Cleveland Open Cup), °C

Thin-film oven test, % loss in mass

Penetration of residue at 25°C, 100g, 5s, 0.1mm, % of original penetration

Solubility in trichloro-ethylene, % by mass

60-70

Min Max

60 70

80-100

Min Max

80 100

120-150

Min Max

120 150

150-200

Min Max

150 200

200-300

Min Max

200 300

300-400

Min Max

300 400

Test MethodASTM

D 5

D 2171

D 2170

User must specify either Figure 1 or Figure 2 for all asphalt grades. Both figures shall not be used simultaneously

230 ---

--- 0.8

52 ---

99 ---

230 ---

--- 0.85

47 ---

99 ---

User must specify either Figure 1 or Figure 2 for all asphalt grades. Both figures shall not be used simultaneously

220 ---

--- 1.3

42 ---

99 ---

220 ---

--- 1.3

40 ---

99 ---

175 ---

--- 1.5

37 ---

99 ---

175 ---

--- 1.5

35 ---

99 ---

D 92

D 1754

D 2042

GRADES OF ASPHALT CEMENT

* All requirements, except for viscosity at 60°C or at 135°C, are the same for Group A, B and C. Minimum viscosity is defined by the bottom line ofeach group as shown in Figure 1 or 2.

Superpave SpecificationSuperpave Specification

Strategic Highway Research Program:– established by US Congress in 1987 as a five-

year, $ 150 million research program to improve the performance and durability of roads in USA

Outcome:– asphalt binder performance related specification

• uses modern physical tests

• weather related

• traffic related

Superpave Specification (Cont’d)Superpave Specification (Cont’d)

Unlike older go - no go specifications Superpave specification determines different levels of asphalt quality

The minimum quality needed for the particular road is also determined

Presently already used in all states in USA (modification in California)

Introduced in Ontario and Quebec Sooner or later will be used across Canada

Superpave Specification (Cont’d)Superpave Specification (Cont’d)

Further developments:– Asphalt binder Expert Task Group (ETG) under

the auspices of Transportation Research Board (US Academy of Sciences) and Federal Highway Administration

– development of parameters and testing methods better related to service performance

– ultimately: development of damage weighted performance models

Superpave Specification (Cont’d)Superpave Specification (Cont’d)

Superpave specification attempts to measure properties that are directly related to pavement field performance

Handling Pump

Permanent Deformation

FatigueCracking

ThermalCracking

Flow

Rutting

Structural Cracking

Low Temp Cracking

Rotational Viscometer

Dynamic Shear Rheometer

Bending Beam RheometerDirect Tension Tester

TEST EQUIPMENTPERFORMANCE PROPERTY

Dynamic Mechanical Analysis by Dynamic Mechanical Analysis by Dynamic Shear RheometerDynamic Shear Rheometer

Stiffness and m-value by Bending Stiffness and m-value by Bending Beam RheometerBeam Rheometer

Tensile Strength and T Critical by Tensile Strength and T Critical by Direct Tension TesterDirect Tension Tester

Superpave Asphalt Binder GradesSuperpave Asphalt Binder Grades

High Temperature Grades(Degrees C)

PG46

PG52

PG58

PG64

PG70

PG76

PG82

Low Temperature Grades(Degrees C)

-34, -40, -46

-10, -16, -22, -28, -34, -40, -46

-16, -22, -28, -34, -40

-10, -16, -22, -28, -34, -40

-10, -16, -22, -28, -34, -40

-10, -16, -22, -28, -34

-10, -16, -22, -28, -34

Performance Graded Asphalt Binder Performance Graded Asphalt Binder Specification Specification

Performance Grade PG46 PG52 PG58-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40

Average 7-day Max PavementDesign Temperature, °C <46 <52 <58Minimum PavementDesign Temperature, °C >-34 >-40 >-46 >-10>-16>-22>-28>-34>-40>-46 >-16>-22>-28>-34>-40

ORIGINAL BINDERFlash Point Temp, T48: Min °C 230Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C 135Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test temp@10 rad/s, °C 46 52 58

ROLLING THIN FILM OVEN (T240) OR THIN FILM OVEN (T179) RESIDUEMass Loss, Maximum, % 1.00Dynamic Shear, TP5: G*/sin , Min, 2.20 kPa Test temp@10 rad/s, °C 46 52 58

PRESSURE AGING VESSEL RESIDUE (PP1)PAV Aging Temp, °C 90 90 100Dynamic Shear, TP5: G*/sin , Min, 5000 kPa Test temp@10 rad/s, °C 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13Physical Hardening REPORTCreep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test Temp, @ 60s, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30Direct Tension, TP3: Failure Strain, Min, 1.0% Test Temp@ 1.0mm/min, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30

PG64-10 -16 -22 -28 -34 -40

<61

>-10 >-16 >-22 >-28 >-34 >-40

64

64

100

31 28 25 22 19 16

0 -6 -12 -18 -24 -30

0 -6 -12 -18 -24 -30

Performance Grade PG46 PG52 PG58-34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40

Average 7-day Max PavementDesign Temperature, °C <46 <52 <58Minimum PavementDesign Temperature, °C >-34 >-40 >-46 >-10>-16>-22>-28>-34>-40>-46 >-16>-22>-28>-34>-40

Flash Point Temp, T48: Min °C 230Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C 135Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test temp@10 rad/s, °C 46 52 58

Mass Loss, Maximum, % 1.00Dynamic Shear, TP5: G*/sin , Min, 2.20 kPa Test temp@10 rad/s, °C 46 52 58

PAV Aging Temp, °C 90 90 100Dynamic Shear, TP5: G*/sin , Min, 5000 kPa Test temp@10 rad/s, °C 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13Physical Hardening REPORTCreep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test Temp, @ 60s, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30Direct Tension, TP3: Failure Strain, Min, 1.0% Test Temp@ 1.0mm/min, °C -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30

Performance Graded Asphalt Binder Specification Performance Graded Asphalt Binder Specification (Cont’d)(Cont’d)

Performance Grade PG70 PG76 PG82-10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34

Average 7-day Max PavementDesign Temperature, °C <70 <76 <82Minimum PavementDesign Temperature, °C >-10 >-16 >-22 >-28 >-34 >-40 >-10 >-16 >-22 >-28 >-34 >-10 >-16 >-22 >-28 >-34

ORIGINAL BINDERFlash Point Temp, T48: Min °C 230Viscosity, ASTM D 4402: Max, 3 Pa.s (3000 cP) Test Temp, °C 135Dynamic Shear, TP5: G*/sin , Min, 1.00 kPa Test temp@10 rad/s, °C 70 76 82

ROLLING THIN FILM OVEN (T240) OR THIN FILM OVEN (T179) RESIDUEMass Loss, Maximum, % 1.00Dynamic Shear, TP5: G*/sin , Min, 2.20 kPa Test temp@10 rad/s, °C 70 76 82

PRESSURE AGING VESSEL RESIDUE (PP1)PAV Aging Temp, °C 100(110) 100(110) 100(110)Dynamic Shear, TP5: G*/sin , Min, 5000 kPa Test temp@10 rad/s, °C 34 31 28 25 22 19 37 34 31 28 22 40 37 34 31 28Physical Hardening REPORTCreep Stiffness, TP1: S, Max, 300 MPa m-value, Min, 0.300 Test Temp, @ 60s, °C 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24Direct Tension, TP3: Failure Strain, Min, 1.0% Test Temp@ 1.0mm/min, °C 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

Superpave PG Grades of Asphalts Superpave PG Grades of Asphalts From Selected Crude OilsFrom Selected Crude Oils

Asphalt CGSB Pen T OfficialGrade 25°C High Low PG Grade

Cold Lake 80/100A 80 64.6 -27.5 92.1 64-22100 62.4 -29.1 91.5 58-28

Bow Valley 80/100A 80 63.1 -24.8 87.9 58-22100 60.9 -26.7 87.6 58-22

Redwater 80/100B 80 59.7 -25.5 85.2 58-22100 57.8 -26.2 84.0 52-22

Foster Creek 80 63.7 -26.6 90.3 58-22100 61.5 -28.2 89.7 58-28

Cold Lake 120/150A 120 60.5 -30.5 91.0 58-28150 58.1 -32.2 90.3 58-28

Bow Valley 120/150A 120 59.0 -28.3 87.3 58-28150 57.7 -30.2 87.9 52-28

Redwater 120/150B 120 56.1 -27.0 83.1 52-22150 54.0 -28.2 82.2 52-28

Foster Creek 120 59.7 -29.5 89.2 58-28150 57.3 -31.2 88.5 52-28

Cold Lake 150/200A 150 58.1 -32.2 90.3 58-28200 54.8 -34.1 88.9 52-34

Bow Valley 150/200A 150 57.7 -30.2 87.9 52-28200 53.5 -32.5 86.0 52-28

Redwater 150/200B 150 54.0 -28.2 82.2 52-28200 51.2 -29.7 80.9 --

Foster Creek 150 57.3 -31.2 88.5 52-28200 54.2 -33.4 87.6 52-28

Service Temperature [°C]

Superpave PG Grades of Asphalts From Selected Superpave PG Grades of Asphalts From Selected Crude Oils Crude Oils (Cont’d)(Cont’d)

Asphalt CGSB Pen T Official

Grade 25°C High Low PG Grade

Cold Lake 200/300A 200 54.8 -34.1 88.9 52-34

300 49.8 -36.1 85.9 46-34

Bow Valley 200/300B 200 53.5 -32.5 86.0 52-28

300 48.6 -35.0 83.6 46-34

Redwater 200/300C 200 51.2 -29.7 80.9 --

300 47.0 -31.7 78.7 --

Foster Creek 200 54.2 -33.4 87.6 52-28

300 49.4 -36.5 85.9 52-34

Cold Lake 300/400A 300 49.8 -36.1 85.9 46-34

400 46.0 -37.2 83.2 46-34

Bow Valley 200/300B 300 48.6 -35.0 83.6 46-34

400 44.9 -36.4 81.3 --

Redwater 300/400C 300 47.0 -31.7 78.7 --

400 43.7 -32.9 76.6 --

Foster Creek 300 49.4 -36.5 85.9 52-34

400 45.8 -38.8 84.6 46-34

`

Service Temperature [°C]

ConclusionsConclusions

Paving asphalt - important international commodity

Alberta - vast reserves of high quality paving asphalt

New US asphalt specification recognizes the difference in product quality

Strong demand for higher quality material Opportunity to export asphalt as a final material

or as heavy crude oil with enhanced value of its distillation residue